When you picture a desert, you probably imagine a vast, empty landscape far from any water. But surprisingly, some of the driest places on Earth lie right beside the ocean. Both the Atacama, in Chile, and the Namib, in southern Africa, stretch along coastlines. So how did these extreme deserts form in places bordered by so much water?

There are three main factors that allow deserts form next to oceans, David Kreamer, a hydrologist at the University of Nevada, Las Vegas, told Live Science: how air moves vertically, how air moves horizontally, and how mountain ranges interact with air moisture.

If you look at a world map, you'll notice that most deserts sit above or below the equator. That's because the equator receives the most direct sunlight and causes the air to warm and rise. As the warm air rises, it creates a low-pressure system — a region where atmospheric pressure is lower than its surrounding area, Kreamer explained. Any moisture in the air cools and condenses into clouds and rain. That's why the regions along the equator are home to lush forests, like the Amazon.

That rising air spreads outward and sinks between 20 and 40 degrees north and south of the equator, and suppresses cloud formation — which explains why there are so many deserts along the subtropical belt, such as the Sahara and the Kalahari.

Then, there is the horizontal movement of air across the planet. Near the equator, trade winds blow from east to west. These winds tend to drop moisture on the eastern sides of continents, leaving their western sides drier. In the case of the Namib, for example, when it does rain, that rain doesn't fall in the desert itself but rather in the mountains to the east, said Abi Stone, a physical geographer at the University of Manchester in England.

Cold ocean currents also play a role. The air that's being blown across the cold current cools on contact with it and picks up some of its moisture, and because of the coldness, the air becomes quite stable. "We kind of envisage packages of air, in some ways, like a balloon, because they don't totally mix, but the balloon skin is really flexible, and they can expand and contract," Stone told Live Science. "The cold air won't tend to do much of that expansion." Without any convection, the pack of air becomes trapped, unable to rise. "But what it can do is hold some moisture, and at the low level, that can get blown on land, and you end up with quite foggy environments at the western part of those coastal deserts," Stone said.

The presence of mountains impacts the dryness of these deserts as well. When moist air is forced over a mountain range, it cools and drops rain on the windward side, Kreamer explained. By the time the air descends on the leeward side, much of its moisture is gone, creating a rain shadow, or an area by the mountains that gets reduced rain. For instance, Seattle, which is located on the western side of the Cascade Mountains, gets an average of 39.3 inches (99.8 centimeters) of rain a year, while Yakima, located on the eastern side of the Cascades, gets an average of 8 inches (20.3 cm) of rain annually.

In the case of the Atacama, Kreamer said, "the wind that comes in South America drops a lot of rain on the east side over the Amazon, and then it hits the Andes. The Andes sap more water off the wind and then right along the coast of South America on the west side, where Chile is," leaving the Atacama exceptionally dry.

These factors give coastal deserts unique characteristics that aren't found in other deserts. They tend to have cooler and more stable climates than inland deserts do, and they're home to plants and animals that have evolved special traits to capture moisture. In the Namib, for example, some beetles harvest water by pointing their butts toward the foggy air.

"People have studied what that surface looks like to make more effective fog nets," Stone said. "There are some amazing creatures."

The formation of polar deserts, like most of Antarctica and the northernmost parts of the Arctic, is driven by many of the same factors as warm coastal deserts. The temperature also plays a role, since the air is so cold in these parts of the world that it can't hold moisture. "In the case of Antarctica, the strong winds and ocean current around the continent is effective at blocking weather systems traveling onto the continent," Stone said.

Equator quiz: Can you name the 13 countries that sit on Earth's central line?

Geologists may have finally solved a longstanding mystery surrounding the Colorado River's largest tributary, which appears to have defied gravity and flowed uphill when it first formed.

The Green River originates in Wyoming and links up with the Colorado River in Canyonlands National Park in Utah. Around 8 million years ago, the Green River carved its way through the 13,000-foot-tall (4,000 meters) Uinta Mountains in northeastern Utah and northwestern Colorado instead of flowing around the formation. But in a new study, researchers argue this isn't possible without a mechanism to lower the mountains.

"It's such a weird path," study lead author Adam Smith, a researcher in numerical modeling at the University of Glasgow in the U.K., told Live Science. "We know from dating and other stuff that the mountain range is 50 million years old and the river has only been running that course since 8 million years ago, but possibly as soon as 2 million years ago."

The Green River flows through the Canyon of Lodore, where it has eroded a ravine with 2,300-foot (700 m) walls. Two competing theories have previously tried to explain why the river ran this course, but neither is particularly convincing, Smith said.

One hypothesis is that the Yampa River to the south of the Uinta Mountains cut northward through the formation and created a channel for the Green River. This would have required a tremendous amount of force, which the Yampa River is unlikely to have produced, because it isn't particularly big. "If this were credible, then you would expect giant canyons running through all mountain ranges, but that's not the case," Smith said.

The other theory is that sediments accumulated and temporarily elevated the Green River so that it overtopped the Uintas and carved its path through them, but the available evidence doesn't support this either. "The sediments that you find here aren't as high as the Canyon of Lodore," Smith said.

Instead, the researchers behind the new study suggest the Uinta Mountains subsided to the point where the Green River could flow over them. The researchers propose that a phenomenon called a "lithospheric drip" tugged the mountains down before a rebound effect caused the landscape to rise upwards once more, resulting in the topography we see today.

The findings were published Monday (Feb. 2) in the Journal of Geophysical Research: Earth Surface.

Lithospheric drips are high-density regions that can form directly beneath mountains, where Earth's crust meets the top of the mantle — the layer of the planet between the crust and the outer core. The weight of the mountains increases the pressure at the base of the crust, forming minerals like garnet that are heavier than mantle rocks. Eventually, these minerals form a blob that drips from the base of the crust, dragging the mountains down and reducing their elevation at Earth's surface.

Lithospheric drips trigger a rebound effect when they finally detach and sink into the mantle. The concept of these drips is relatively recent, but evidence of them has been found in several places, including the Andes. "They can happen wherever you have had a mountain range form, and they can happen at any time," Smith said.

A telltale sign of lithospheric dripping is a bullseye-like pattern of uplift on Earth's surface. Smith and his colleagues modeled geological processes in the Uinta Mountains based on the unusual profiles of rivers there and found such a pattern.

The researchers also analyzed seismic tomography images — 3D maps of Earth's interior that are created using seismic waves — from a previous study. They found a blob 120 miles (200 kilometers) deep in the mantle beneath the Uintas that looked very much like an old lithospheric drip, providing strong evidence for this mechanism, Smith said.

Next, the researchers used the observed drip's depth and size to calculate when it detached from the bottom of the Uinta Mountains. They found that it likely broke free between 2 million and 5 million years ago, which fitted with the model's predictions of when the mountains rebounded and matches estimates of when the Green River first cut through the mountains.

The drip lowered the mountains so much that they became "the path of least resistance," Smith said. Once the Green River started flowing over the Uintas, it kept incising the mountains, creating structures like the Canyon of Lodore, he added.

Other experts who weren't involved in the research suggested this explanation could ultimately solve the longstanding mystery.

Mitchell McMillan, a research geologist at the Georgia Institute of Technology, said that lithospheric dripping is a plausible explanation for why the Green River flows the way that it does.

"The most exciting aspect of this study is that it uses clues on Earth's surface to understand mantle processes and how they might affect mountain belts," McMillan told Live Science in an email. "Whether or not the drip hypothesis ultimately ends up being correct here, this study is a valuable demonstration of such an approach."

As the name suggests, China's Rainbow Mountains are multicolored formations in the northwest of the country. The landscape in this region is otherworldly, with vibrant bands that look like they were spray-painted onto the rocks.

The Rainbow Mountains are located in the foothills of the rugged Qilian mountains and likely formed around the same time as the Himalayas, approximately 50 million years ago, according to NASA's Earth Observatory. Land that was once relatively flat was scrunched up and folded into jagged terrain when the Indian tectonic plate collided with the Eurasian plate. This was because these plates have a similar rock density, so neither could slip beneath the other to form a subduction zone, according to the U.S. Geological Survey (USGS).

But the basis for the mountains' rainbow pattern was laid long before the epic collision.

Related: Massive tectonic collision causing Himalayas to grow may also be splitting Tibet apart

The Rainbow Mountains are made of sandstone and siltstone — sedimentary rocks that form when sand and silt, respectively, are compacted and cemented together over long periods of time. These rocks — with their bands of different colors — were deposited before the Himalayas formed.

The colorful bands are the result of iron and other trace minerals in the stone. Each band has a different composition that determines its pigment. For example, the deep red stripes are rich in iron oxides, the yellow layers contain abundant iron sulfide and the green bands hold more chlorite and iron silicates, according to a 2016 article in Forbes.

Iron and other minerals accumulated in the rock while the sand and silt grains were still cementing together. Groundwater circulating in the pore space between the grains deposited the minerals, coating each grain and further gluing the rocks together.

The slanted bands we see on the flanks of the Rainbow Mountains today are upturned layers that would have remained buried and horizontal had the Indian and Eurasian plates not smashed into each other. The bunching of the land by plate tectonics was followed by intense erosion, which wiped away any sediment covering the colorful layers. Luckily for modern visitors, there is no vegetation to obscure the striking rainbow pattern.

The Rainbow Mountains are a popular tourist attraction. They are protected as part of the Zhangye Danxia National Geopark, but visitors can climb to the top of the hills and admire the view using wooden stairs and platforms.

Discover more incredible places, where we highlight the fantastic history and science behind some of the most dramatic landscapes on Earth.

Mountain fly maggots have evolved fake faces on their butts as a cunning disguise to infiltrate termite colonies, a new study has found.

Researchers spotted the fake faces, which resemble termite heads, on the rear of a previously unknown blow fly larva living in the mountains of Morocco. These faces are part of an extreme mimicking strategy that trick harvester termites (Anacanthotermes ochraceus) into thinking the fly larvae are part of their colony.

Soldier termites typically kill colony intruders on site, but disguised larvae live among the soldiers without any problems and are granted full access to the termite mound's food chamber. The disguise is so good that the termites even appear to groom the guileful grubs, according to the study published Monday (Feb. 10) in the journal Current Biology.

Researchers discovered the two-faced larvae by chance while looking for ants in the Anti-Atlas mountain range in southern Morocco. The team lifted a stone and found a termite mound with three of the never-before-seen fly larvae inside, study lead author Roger Vila, a scientist at the Institute of Evolutionary Biology in Spain, explained in a statement.

"It must be an extremely rare species, because we have made three more expeditions in that area and, despite lifting hundreds of stones, we found only two more flies, together, in another termite mound," Vila said.

Related: Kamikaze termites blow themselves up with 'explosive' backpacks — and scientists just figured out how

Termite nests are protected, food-rich habitats for any species cunning enough to get inside. The fly's strategy is one of social integration, which requires extreme morphological, behavioral and physiological adaptations to pull off, according to the study.

Researchers collected the disguised fly larvae and termites and took them back to the lab for further study, and found a number of extreme adaptations. For example, the larvae had modified breathing holes to act as fake termite eyes and modified sensory organs called papillae that resembled termite antennae.

Chemical disguise

The larvae have also evolved scent chemicals to match the termites' unique odor. Vila noted that the team studied the chemical composition of the larvae and found they were indistinguishable from the termites in the colonies where they lived.

"They smell exactly the same," Vila said. "In addition, the larvae and termites in a particular colony have slight differences in their chemical profile that differentiate them from other termite mounds. This odour is key to interacting with the termites and benefiting from their communal life. It is a chemical disguise."

The researchers found that the larvae were part of the fly genus Rhyncomya. No other member of this group is known to do this kind of mimicry, so the team suspects the larvae are a newfound species. However, the team was unable to raise the larvae to adulthood to be sure as they all died in the lab before they were able to mature.

Villa noted that there may be elements of the termite nest and the relationship between the two species that they were unable to transfer to the lab.

"Their diet is currently unknown, and their adult form remains a mystery," Vila added.

Mount Everest is the world's tallest mountain as measured from sea level. But will it hold that title forever?

To answer this question, first we must understand how mountains form and how Mount Everest and the rest of the Himalayas got so tall. One way tall mountains form is when two tectonic plates collide. As one begins to subduct — or move under — the other, crust gets mushed around, upheaved, and turned into mountains.

According to Rob Butler, a geologist at the University of Aberdeen in Scotland, the heights of the mountains that form during these collisions depend on many factors. These characteristics include the thickness of the crust, which is determined by the intensity and length of the tectonic collision, and the crust's temperature, which is determined by its age.

"Think of the crust not as a solid, but as a viscous liquid, like maple syrup," Butler told Live Science. Like cold maple syrup, cold crust is more viscous and, therefore, firmer. So thicker, colder crust can form taller mountains than thinner, warmer crust can.

Other than the thickness and temperature of the crust, the most important factor in determining the height and growth of mountains is erosion.

Related: What's the oldest mountain range in the world? (How about the youngest?)

"It's because erosion is so effective that [the Himalayas] are one of the fastest rising systems of rocks on the planet," Butler said. This is because of a principle called isostasy. Much like a container ship floating in the ocean, the less material that's stacked on Earth's crust, the higher it floats above the mantle, the planet's middle layer.

So the more material that is transported away from a mountain — whether via a river, a glacier or heavy rains and landslides — the more the mountains around it can rise. In fact, a 2024 study found that the rapid erosion of a river network more than 45 miles (72 kilometers) from Mount Everest helped the peak grow between 49 and 164 feet (15 and 50 meters) in the past 89,000 years.

Although erosion is one factor in mountains' growth, it is also part of what causes them to shrink, explained Matthew Fox, co-author of the study and a geologist at University College London. "[Whether mountains grow or shrink] depends on this balance between the rates of erosion and the rates of uplift," Fox told Live Science. If the rate of uplift is higher, the mountain will grow. If the rate of erosion is higher, the mountain will shrink.

Some scientists have suggested that Nanga Parbat, one of Everest's Himalayan neighbors and the ninth-tallest mountain on Earth, is growing fast enough to one day overtake Everest in height. However, Butler and Fox doubt this will happen. Although Nanga Parbat is growing faster than Everest due to rapid erosion, it is also eroding faster due to the intensity of monsoons in that area. In contrast, Everest is growing and eroding more slowly, leaving it at a fairly constant 2,000 feet (610 m) taller than Nanga Parbat.

However, Butler doesn't discount the possibility that another Himalayan mountain may take the throne someday. Weather factors could change over time, he said, causing shifts in the peaks' growth rates. "[Tectonic collision in the Himalayas] is going to continue for another 10 million years," Butler said. "There's plenty of time to juggle these variables around a bit."

Nonetheless, Butler thinks it's unlikely there will ever be a peak significantly taller than Everest. The Himalayas sit in the sweet spot; they formed due to a very intense and long collision event with cold crust and high erosion rates due to monsoons. They were also penned in by surrounding mountain ranges, leaving little room for the crust to escape during the collision.

"If you squash things, they've got to go up or sideways," Butler told Live Science. "And when sideways is taken, they've got nowhere to go but up."

It's very rare for all of these factors to line up, Butler said, and it might not have happened before the Himalayas. Moreover, on Earth, gravity is too powerful to allow a mountain to get much taller than Everest's current height.

"If we're talking a few meters, or even a few hundred meters, there's every possibility that another mountain could overtake Everest," Butler told Live Science. "But in terms of doing something significant, like peaks that are 10 kilometers [6 miles] high, I would think probably not."

Earth's crust may "drip" into its middle layer under growing mountain ranges.

This odd process, called lithospheric dripping, has been proposed to occur under the Andes, in Central Asia, in the U.S. Pacific Northwest and along the west coast of Canada. Now, researchers have found that the Anatolian plateau in Turkey is undergoing a similar process.

The findings could reveal how mountains and basins are built on planets like Venus or Mars, where there are no mobile tectonic plates like the ones that crumple into one another to create topography on Earth.

"It's [about] understanding how tectonics might work on planets that don't have plates," said study author A. Julia Andersen, a doctoral student in tectonophysics at the University of Toronto. "Earth is the only planet we know of that has plates in the solar system, but the other planets aren't flat."

Volcanic eruptions can spill lava on these planetary surfaces. But landforms can also be created when the lithosphere, which consists of the crust and the relatively brittle upper layer of the mantle, gets especially thick. Mountains create a lot of pressure on the lower lithosphere. In the high-pressure zones underneath the towering peaks, new mineralization can occur, Andersen told Live Science. Some of these minerals are denser than the mantle below.

Related: 'Many more ancient structures waiting to be discovered': Lost chunk of seafloor hidden in Earth's mantle found off Easter Island

"In any sort of physical system, if you have a higher-density material on top of a lower-density material, then it sinks or drips," she said.

But the idea is still controversial, said Mitchell McMillan, a geoscientist at Georgia Tech who was not involved in the research. McMillan also thinks lithospheric dripping is likely happening on Earth, but it can be hard to untangle the signs of possible dripping from the geology created by the tectonic plates' horizontal movements.

One possible sign is that lithospheric dripping can pull the crust above into wrinkly ridges and valleys, forming small-scale mountains. In Turkey, though, there was no such telltale sign of hidden dripping. Previous research had shown that seismic waves traveling through the crust under the massive Anatolian plateau moved faster than average, suggesting some difference in density and temperature in those areas. At the surface, the only indication that something odd might be happening was the Konya Basin, a vaguely circular basin of about 1,620 square miles (4,196 square kilometers) in the southern portion of the plateau.

Andersen and her team conducted a geophysical analysis of the basin's topography and set up a lab-bench experiment to mimic the formation of this large depression.

They used a thick, gooey polymer to represent the middle mantle, and a mix of clay and the polymer for the more rigid upper mantle, topping it off with a silica-and-ceramic "crust." When left to sit, the clay-polymer layer began to drip into the faux mantle. Notably, the "crust" on top wasn't disturbed. Over time, a second drip event began, still leaving the surface unmarred.

The analysis of the real Konya Basin indicates that the same thing is occurring there, Andersen said. "The data indicated that, yes, there is a drip happening there, even if we aren't necessarily seeing many features in the crust that would indicate that it's happening," she said.

This method allowed for more detail than computer modeling alone would show, McMillan told Live Science. "Physical models like Dr. Andersen's are great because they show some results that our numerical models wouldn't be able to resolve," he said. "This is important for interpreting existing data."

The study, published Sept. 13 in the journal Nature Communications, suggests that a similar process could occur around many mountain ranges around the world, Andersen said. Next, she'd like to investigate lithospheric dripping under the Appalachian Mountains, which were once at least as high as the modern Himalayas.

People buried in avalanches are more likely to be rescued quickly and survive the experience today than they were four decades ago, a new study suggests.

Avalanches can kill in a number of ways. Most people caught in these snow flows die of injuries sustained during the avalanche, suffocation after being buried by snow, or hypothermia that sets in as they await rescue. Time is critical — most people who live to tell the tale are rescued within the first few minutes after burial.

The first in-depth studies of avalanche survival were published only 30 years ago and focused on incidents in the Swiss Alps. At that time, fewer than half of the people buried in avalanches survived, and almost all of those who did survive had been rescued within 15 minutes of burial.

Since the 1990s, though, we've developed more reliable ways to predict avalanches, as well as new technologies to improve people's chances of being found and rescued quickly. The new research shows that these advancements have improved avalanche survival.

Related: Body of climber missing for nearly 40 years discovered in melting Swiss glacier

The study, published Sept. 25 in the journal JAMA Network Open, examined records of avalanche survival in Switzerland that were published between 1981 and 2020. Within those four decades, more than 7,000 people were caught in avalanches, including 1,643 people who were "critically buried," meaning snow covered their head and chest.

"If a person caught in an avalanche remains on the surface or is only partially buried, with the head and chest exposed, the survival rate exceeds 90%," said Dr. Hermann Brugger, co-author of the study and founder of the Institute for Mountain Emergency Medicine in Bolzano, Italy. That percentage is based on all reports from 1981 to 1998.

"However, when the head and chest are fully buried, survival drops significantly to around 53%," Brugger told Live Science in an email.

The new research shows that, since 1990, the overall avalanche survival rate in Switzerland has increased from 43.5% to 53.4% — that amounts to about 10 more people saved out of every 100 affected.

That survival rate may still sound low, but time makes a big difference. People buried for less than 10 minutes had a 91% chance of survival, but their odds dropped to 76% after just five more minutes. By the 30-minute mark, fewer than 1 in 3 people survive.

"After 10 minutes of burial, the victim begins to suffer from hypoxia (oxygen deprivation) and hypercapnia (buildup of carbon dioxide)," Brugger said. "Exhaled carbon dioxide accumulates in the surrounding snow, reaching toxic levels that are then rebreathed by the victim."

People who are in a group when an avalanche happens can react immediately to locate and dig out their companions, so they can often help within that crucial 10-minute window. Organized rescue teams take longer — but the average time to rescue has fallen from 45 minutes to 25 minutes over the past 40 years, the new study finds.

"Improvements in the survival rate could highlight new medical treatments after extrication or quicker organized rescue give victims a better chance of survival," said Pascal Haegeli, an avalanche risk management expert at Simon Fraser University who was not involved in the study.

The study authors attribute this success to better avalanche safety training for outdoor-sports enthusiasts and new technologies that enable rescuers to find victims faster. This tech includes digital transceivers that broadcast a survivor's location and wearable radar reflectors that can be pinged from handheld detectors or from the air.

Because the study relied on data recorded between 1981 and 2020, some information — especially on how long survivors were buried — was missing. The researchers used statistical methods to help fill in the gaps, but more real-world records are needed to gain additional insight into what makes a difference in avalanche survival.

That said, "these results may not be fully applicable to other regions, because North America experiences higher rates of trauma in avalanche accidents than Europe due to more trees in areas where avalanches occur," said Simon Horton, a researcher and forecaster with Avalanche Canada who was not involved in the study. Other factors, such as changes in snow’s properties over time, may also shape survival trends, he added.

Brugger emphasized that the safest approach is to avoid situations where you might encounter an avalanche in the first place. He suggested carefully reviewing the weather forecast and the current "avalanche danger scale," which uses weather and snow conditions to predict the likelihood of an avalanche — and just how large and dangerous that avalanche might be. Mountaineers should plan their routes accordingly, ensuring that they make adjustments based on the level of avalanche risk in a given area.

"Carry appropriate safety gear, including an avalanche beacon, shovel, probe and possibly an avalanche airbag," which can be deployed during an avalanche to increase a person's size and make them harder to bury, Brugger added. "In the event of an avalanche, the priority is to keep your airway clear by attempting to place your hands over your mouth and nose. And, finally, never go alone."

Editor's note: This article was updated on Oct. 3, 2024, to include quotes from two experts not involved in the research. The story was first published on Oct. 2.

This article is for informational purposes only and is not meant to offer medical or mountaineering advice.

Ever wonder why some people build muscle more easily than others or why freckles come out in the sun? Send us your questions about how the human body works to community@livescience.com with the subject line "Health Desk Q," and you may see your question answered on the website!

The Yarlung Tsangpo Grand Canyon is the world's largest terrestrial canyon — longer than even the Grand Canyon in Arizona and deeper than every other known canyon on land (the Mariana Trench in the Pacific Ocean surpasses it).

The canyon is named after the Yarlung Tsangpo River, which adventurers have dubbed the "Everest of rivers," because it is mostly inaccessible and has the highest average elevation, at 13,000 feet (4,000 meters), of any major river on Earth. The headwaters of the Yarlung Tsangpo are located in the west of the Tibet Autonomous Region at Angsi Glacier, and the river then meanders east across the Tibetan Plateau before bending sharply southwestward to join up with the Brahmaputra River.

Related: Is Mount Everest really the tallest mountain on Earth?

Yarlung Tsangpo Grand Canyon is 314 miles (505 kilometers) long, which is 37 miles (60 km) longer than the Grand Canyon. It includes some of the most rugged and least-explored places in the world, including a treacherous section in the southeastern Tibet Autonomous Region, where it passes between two towering peaks: Namcha Barwa, which stands 25,530 feet (7,782 m) tall, and Gyala Peri, which sits slightly lower, at 23,930 feet (7,294 m).

The canyon dips to its deepest point along this stretch, reaching 19,715 feet (6,009 m) from top to bottom, or three times as deep as the Grand Canyon. The Yarlung Tsangpo Grand Canyon has an average depth of 7,440 feet (2,270 m).

The canyon formed when tectonic forces pushed up Earth's crust around 3 million years ago and steepened the path of the Yarlung Tsangpo River, which then caused massive erosion, Live Science previously reported.

And as if it weren't breaking enough records already, the canyon is also home to the tallest tree ever discovered in Asia — a 335-foot-tall (102 m) cypress that would overshadow the Statue of Liberty. A research team from Peking University measured the tree in May 2023 as part of an ecological survey to help preserve the unique ecosystem of the Tibet Autonomous Region.

It's unclear which species the tree belongs to, although Chinese state media publications at the time suggested it could be a Himalayan cypress (Cupressus torulosa) or a Tibetan cypress (Cupressus gigantea).

Below is a full-length picture of Asia's tallest tree.

Discover more incredible places, where we highlight the fantastic history and science behind some of the most dramatic landscapes on Earth.

Over 400 million years ago, an upwelling of hot rock from Earth's mantle wrenched apart the crust in Mongolia, creating an ocean that survived for 115 million years. 

The geological history of this ocean could help researchers understand Wilson cycles, or the process by which supercontinents break apart and come together. These are slow, broad-scale processes that progress by less than an inch per year, said study co-author Daniel Pastor-Galán, a geoscientist at the National Spanish Research Council in Madrid. 

"It's telling us about processes in the earth that are not very easy to understand and that are also not very easy to see," Pastor-Galán told Live Science. 

Geoscientists can fairly accurately reconstruct the breakup of the last supercontinent, Pangea, 250 million years ago. But prior to that, it's difficult to model exactly how the mantle and the crust interacted. 

In a new study, researchers were intrigued by volcanic rocks in northwestern Mongolia from the Devonian period (419 million to 359 million years ago). 

The Devonian was the "Age of the Fishes," when fish dominated the oceans and plants began to spread on land. At the time, there were two major continents, Laurentia and Gondwana, as well as a long stretch of microcontinents that would eventually become what is now Asia. These microcontinents gradually bumped up against each other and merged in a process called accretion. 

The researchers began doing fieldwork in northwest Mongolia where rocks from these continent-building collisions are exposed on the surface, in 2019, studying the ages and chemistry of the ancient rock layers. They found that between about 410 million and 415 million years ago, an ocean called the Mongol-Okhotsk Ocean opened up in the region. The chemistry of the volcanic rocks that accompanied this rift revealed the presence of a mantle plume — a stream of particularly hot, buoyant mantle rock.

Related: Columbia, Rodinia and Pangaea — A history of Earth's supercontinents

"Mantle plumes are usually involved in the first stage of the Wilson cycle: breakup of continents and opening of ocean, such as the Atlantic Ocean," study lead author Mingshuai Zhu, a professor of geology and geophysics at the Chinese Academy of Sciences, told Live Science. 

In many cases, this happens right in the middle of a solid chunk of continent, tearing it apart. In this case, though, the geology is particularly complex, because the plume was tearing apart crust that had previously come together through accretion. Weak spots between the accreted microcontinents, combined with the plume, probably helped the ocean to form, Zhu said. The researchers published their findings May 16 in the journal Geophysical Research Letters. 

The ocean closed in the same spot that it opened, which is a common pattern in ocean life-cycles, Pastor-Galán said, but researchers only looked at a snapshot of the ocean's opening in this study. 

"A good thing is that a hotspot is relatively stable so they keep on, for many millions of years, in the same place," Pastor-Galán said. As continents in the crust move over the mantle hotspot, the hotspot leaves behind volcanic rocks and a tell-tale chemistry; this helps researchers track plate motion over millennia, he said. 

Asia is no longer accreting new microcontinents, Pastor-Galán said, but the formation of the Mongol-Okhotsk Ocean was probably similar to what is seen today at the Red Sea, where the crust is spreading by about 0.4 inches (1 centimeter) per year. The Red Sea is part of a larger continental rift that could create a brand-new ocean in eastern Africa over tens of millions of years, though geologists don't yet know whether other continental forces will prevent that ocean from fully opening, according to Eos magazine. 

Zhu and his colleagues now plan to use their data to make computer models to better describe the complicated tectonics of the ancient Devonian ocean. 

A Colombian mountain range has lost its "roots" — a wedge of Earth's crust that once propped it up but has since "dripped" down into the mantle, a new study suggests. It's long been a mystery as to how the peaks have managed to stay upright, but now, researchers are investigating the underlying geology.

The Sierra Nevada de Santa Marta, a mountainous region in northwestern Colombia with peaks that stand over 18,700 feet (5,700 meters) tall, has perplexed geologists since the 1970s, when measurements indicated the crust beneath the peaks was unusually thin.

"Mountain regions typically have thick crustal roots that compensate for the load of the mountains," study lead author David Quiroga, a geophysicist and former graduate researcher at the University of Alberta in Canada, told Live Science in an email. Earth's crust is much lighter than the underlying mantle, Quiroga said. Because mountains are so heavy, the crustal roots that sit beneath them are embedded in the mantle. The mass displaced within the mantle is larger than that of the crustal root, and this configuration makes up for the load piled on by mountains that sit above.

Geophysicists can determine the thickness of Earth's crust using gravity anomaly measurements. "In general, there is high gravity in places where there is a lot of mass, and vice-versa," Quiroga said. The presence of a crustal root in mountainous regions usually produces negative gravity anomaly values, meaning the mass in this region is lower than expected. This reflects where the lighter crust has displaced the heavy mantle, unlike other places where the mantle is intact.

"However, in the case of the Sierra Nevada de Santa Marta, in Colombia, there is an elevated mountain region with a high positive gravity anomaly," Quiroga said. "This means that instead of having a mass deficit, there is an excess of mass."

Related: 6 million-year-old 'fossil groundwater pool' discovered deep beneath Sicilian mountains 

The mountain range once had a crustal root to make up for its huge load — but this root slowly oozed down into the mantle over a period of 10 million years, according to the study, which was published Jan. 7 in the Journal of Geophysical Research: Solid Earth. 

Earth's crust and the uppermost mantle form a rigid shell around our planet known as the lithosphere. The lower lithosphere may "drip" down in places where it is heavier and colder than the mantle below, Quiroga said. The mantle then rises to fill the gaps and heats up the lower crust, which can trigger changes in its composition that cause bigger portions of the crust to sink.

Previous research has suggested lithospheric dripping may explain unusual geological formations and dynamics in other regions — including the Puna Plateau in the Andes, the Sierra Nevada in California and the Wallowa mountains in Oregon. But Quiroga and his colleagues are "the first to propose that such a mechanism is a plausible explanation for the Sierra Nevada de Santa Marta," he said.

It's unclear how the Colombian mountain range has managed to stay upright despite its apparent lack of support, but the devil could be in the details. 

"The models in our study show that once the mountain region loses its crustal root it starts sinking due to the loss of support," Quiroga said. "Because the mountain is still upright and tall, this suggests that the removal episode must have occurred very recently and that there has not been enough time for the mountain to collapse."

The peaks may have lost their roots as recently as 2 million years ago, Quiroga said. In the study, the researchers also suggest a possible window for dripping occurred between 56 million and 40 million years ago, during the Eocene epoch This later time frame implies the mountains have remained upright for over 40 million years, which is inconsistent with models in the study that predicted collapse after just 5 million years.

But other factors not included in the models might have propped the mountains up over the ages. The surrounding lithosphere may be strong enough to provide the peaks support from either side, and the mantle may have risen to delay the mountains from crumbling, Quiroga said. The Caribbean tectonic plate, which is sliding beneath Colombia, should also be considered as a potential prop in future models, he added.

Until then, the mystery surrounding the Sierra Nevada de Santa Marta lives on.

Editor's note: This story was updated on Feb. 5 to reflect that previous studies linked lithospheric dripping to unusual surface expressions, not to positive gravity anomalies, as was originally stated.

Earth is speckled with mountains, from the slight Mount Wycheproof, rising 482 feet (147 meters) above sea level in Victoria, Australia, to the highest mountain on Earth, Mount Everest, standing 29,032 feet (8,849 meters) tall. But how do these puny to gigantic peaks form?

Mountains are born in a number of ways, many of which are linked to Earth's tectonic plates. When these giant slabs of rocks collide, their edges can buckle and fold, which forces rock up to form a mountain range. The Himalayas, which are home to Mount Everest, formed in this manner.

Sometimes, when tectonic plates meet, one ends up diving under the other — a phenomenon known as subduction. The rock that crumples up at the edges can give rise to mountain ranges such as the Andes, according to the University of California Museum of Paleontology.

Mountains can also form when tectonic plates split. The blocks of rock on each side of the resulting rift can form mountain ranges such as the Sierra Nevada in the western United States, the University of California Museum of Paleontology noted.

Volcanism is another way mountains can arise. Subduction zones often host volcanoes, leading to island arcs such as the isles of Japan, according to James Madison University's geology department. In addition, giant pillars of hot rock known as mantle plumes can rise from near Earth's core to sear overlying material like a blowtorch, forming volcanic islands such as the Galapagos.

Related: What's the highest a mountain can grow on Earth?

Curiously, erosion can help drive mountain growth as well. For instance, "glaciers or rivers running off the slope of mountains erode materials with them," Lijun Liu, a geoscientist at the University of Illinois Urbana-Champaign, told Live Science. This lifts weight off Earth's crust, driving the soft mantle underneath to rebound upward and leading mountain peaks to rise, he noted in a 2014 study.

Moreover, geologists are discovering that activity deep within the Earth may play a role in building mountains, Jonny Wu, a geodynamicist at the University of Arizona in Tucson, told Live Science.

For example, recent findings suggest that chunks of dense rock can peel off the bottom of tectonic plates and fall into the mantle beneath it, which may cause the underlying surface to buoy upward, Liu said.

Such delamination could help explain how high mountains or plateaus can form within the interiors of continents, such as the Rocky Mountains and the Colorado Plateau, Liu said. It might also help explain high elevations in the Tibetan Plateau, Sean Gallen, a geomorphologist at Colorado State University in Fort Collins, told Live Science.

In addition, rock in the mantle churns on million-year timescales — a phenomenon known as dynamic topography, Wu said. This churning can warp Earth's surface upward, he noted. However, it remains debated how much dynamic topography can actually change Earth's surface, Gregory Ruetenik, a researcher at the Czech Academy of Sciences' Institute of Geophysics, noted in a 2023 commentary in the journal Nature Geoscience.

Furthermore, as subducting tectonic plates descend, they may interact with layers of the mantle or churning flows. These slab-mantle interactions can trigger a chain reaction that is felt at the surface, causing mountains to rise or fall, Wu said.

"Examples where these types of processes have been used to explain mountain-building histories include parts of the Andes and certain subduction zones in the Mediterranean," Gallen said.

All in all, "mountain building profoundly shapes the Earth on which we live," Wu said. Mountains influence climate and weather, and the erosion and weathering of sediments from mountain ranges have a significant chemical impact on the planet's surface, oceans and atmosphere, he explained.

Although mountains are important to life on Earth, "we still don't fully understand how they form and change through time," Gallen said. "That's why I find them so exciting to study."

The Himalayas, which include the world's tallest mountains, weren't born the way geoscientists thought. The tectonic plates that collided to form the peaks 45 million to 59 million years ago were already pushing against each other, causing the Himalayan mountains to rise to more than half their current elevation, before the big crash gave them a violent shunt upward, scientists say.

This means the iconic mountains may have started their ascent into the sky far earlier than previously believed — around 63 million to 61 million years ago — due to the subduction of the oceanic part of the Indian tectonic plate.

"Previously it was assumed that continent-continent collision (India plate with Eurasian plate) was required for such high elevation to be obtained," study lead author Daniel Enrique Ibarra, an assistant professor of Earth, environmental and planetary sciences at Brown University, told Live science in an email.

In a new study published Thursday (Aug. 10) in the journal Nature Geoscience, Ibarra and his colleagues found that the Himalayas attained roughly 60% of their current elevation before the continental plates collided. The discovery may influence our understanding of the region's climate in the past, they said, and challenge assumptions about how other mountainous areas, such as the Andes and the Sierra Nevada, formed.

Related: Is Mount Everest really the tallest mountain on Earth?

"Our study shows for the first time that the edges of the two tectonic plates were already quite high prior to the collision that created the Himalayas — about 3.5 kilometers [2.2 miles] on average," senior study author Page Chamberlain, a professor of Earth and planetary sciences at Stanford University, said in a statement.

The Himalayas now have an average elevation of 20,000 feet (6,100 meters) and host the world's tallest mountain, Mount Everest, which towers 29,032 feet (8,849 m) above sea level. 

The researchers reconstructed the mountain range's past by measuring the amount of different versions, or isotopes, of oxygen in its sedimentary rocks — a technique called triple oxygen analysis that is typically used to study meteorites.

The windward slope of a mountain — the first to be hit by air circulating around the mountain — gets more rain than the opposite side, known as the leeward slope. The chemical composition of this rain changes as the air moves up the windward slope towards the mountain's peak, with heavier isotopes of oxygen declining at lower altitudes and lighter isotopes dropping out near the top.

By tracking these changes, the researchers determined the historic altitude of rocks. They found the makeup around 62 million years ago was consistent with an elevation of 11,480 feet (3,500 m). "That's a lot higher than many thought," Ibarra said in the statement.

This initial uplift may have been caused by the oceanic part of the Indian tectonic plate, which at that time was pushing its way underneath the continental slabs at a low angle and forcing the overriding plate up.

So, "the oceanic part of the India plate initiated convergence," Ibarra told Live Science. "This gave the roughly 60% elevation that we find in our study."

A huge collision 45 million to 59 million years ago then forced the edges of the Indian and Eurasian tectonic plates up by an additional 0.6 miles (1 km), according to the study. These tectonic forces are ongoing and contribute to the growth of the mountains even today. "The final push is the onset (and continuation today) of continent-continent collision," Ibarra said.

The discovery could help explain several climatic phenomena, including the establishment of the east and south Asian monsoon system, according to the study.

"This new understanding could reshape theories about past climate and biodiversity," Ibarra said in the statement. 

Reaching 29,032 feet (8,849 meters) above sea level, Mount Everest is the highest mountain on Earth. Located in the Mahalangur Himal section of the Himalayas, the mountain's summit straddles the border separating Tibet and Nepal.

Who were the first explorers to climb Everest?

Mount Everest has two main climbing routes: the southeast ridge from Nepal, and the north ridge from Tibet. Though the north ridge route is shorter, today most climbers use the southeast ridge route, which is technically easier.

The northern approach was charted in 1921 by George Mallory during the British Reconnaissance Expedition, which was an exploratory expedition that was not intended to attempt the summit, according to UM. Mallory was famously, perhaps apocryphally, quoted as answering the question "Why do you want to climb Mount Everest?" with the reply, "Because it's there," according to The Ohio State University Department of History.

In 1922, Mallory and fellow Brits Geoffrey Bruce and Charles Granville Bruce, along with Austrian chemist George Finch, attempted an ascent for the first time using oxygen, but the expedition was thwarted by an avalanche, according to UM.

In June 1924, Mallory and English mountaineer Andrew Irvine attempted to reach the summit, but they did not survive. A 1999 expedition found Mallory's body. As the ice continues to melt due to climate change, more and more bodies have been recovered in recent years, Live Science previously reported.

Early expeditions in the 1920s and 1930s attempted to make the ascent from the Tibetan side, but access was closed after Tibet officially came under Chinese control in 1951. This spurred English explorer Bill Tilman and a small party that included Americans Charles Houston, Oscar Houston and Betsy Cowles to approach Everest through Nepal along the route that has developed into the standard approach to Everest from the south, researchers reported in 1992 in The Geographical Journal.

In 1952, members of a Swiss expedition led by Edouard Wyss-Dunant reached a height of about 28,199 feet (8,595 m) on the southeast ridge, setting a new climbing altitude record, according to the Swiss Foundations for Alpine Research. Tenzing Norgay, a member of this expedition and a Nepalese Sherpa, took part in the British expedition the following year.

In 1953, a British expedition led by John Hunt returned to Nepal. Hunt selected two climbing pairs to attempt to reach the summit, Charles Wylie, a British Army lieutenant colonel and the organizing secretary to the expedition, wrote in The Himalayan Journal. The first pair — Tom Bourdillon and Charles Evans — came within 300 feet (91 m) of the summit but had to turn back due to oxygen problems. Two days later, the second pair — New Zealand mountaineer Edmund Hillary and Norgay — reached the summit, took some pictures and left some sweets and a cross, Wylie reported in 1954.

Today, the mountain is becoming both less difficult and more treacherous to climb. A 2022 study published in the journal NPJ Climate and Atmospheric Science showed that Everest's glaciers are melting rapidly due to climate change, making avalanches more frequent. The South Col Glacier — the world's highest — has thinned by more than 180 feet (55 m) over the past 25 years, Live Science reported. However, warmer temperatures and ice loss have made it easier for hikers to summit the mountain.

However, technology has made climbing safer, Arnette said. Supplemental oxygen is easier to obtain these days, and if you find yourself stranded, "at a minimum, they'll get a helicopter and fly you off."

When was Everest first measured?

The height of Mount Everest was first determined in 1856, according to the University of Montana Department of Geography (UM). At the time, the Great Trigonometric Survey of British India pegged the height of the mountain, known to them as Peak XV, at 29,002 feet (8,840 m). But those surveyors were at a disadvantage because Nepal would not grant them entry due to concerns that the country would be invaded or annexed, UM says. The current accepted elevation was determined by a joint Chinese-Nepalese survey in November 2021, though technically, Everest's height is in flux; the mountain is simultaneously growing from tectonic-plate activity, according to the U.S. Geological Survey and "shrinking" from sea level rise, Live Science previously reported. 

In 1865, Andrew Waugh, the British Surveyor General of India, suggested that the mountain be named in honor of his predecessor in the job, Sir George Everest, according to a study published in 1931 in the journal Nature. The Tibetans had referred to the mountain as "Chomolungma," or Holy Mother, for centuries, but Waugh did not know this because Nepal and Tibet were closed to outsiders.

Mount Everest attracts experienced mountaineers and less-seasoned climbers from around the world, who typically enlist local guides from the Sherpa people, a Tibetan ethnic group renowned for their knowledge of the Himalayan range and skill in climbing, according to the American Himalayan Foundation. Climbing the more than 11,000 feet (3,350 m) from base camp to the summit in a low-oxygen environment is no easy feat. Altitude sickness, weather, wind and, in rare cases, altitude-induced psychosis are the major roadblocks to summiting the peak.

"It's like holding your breath and climbing a set of stairs," veteran climber and record keeper Alan Arnette told Live Science. "But not just any stairs — it's more like the Empire State Building." More than 6,000 people have summited Everest, and more than 300 have died trying, according to the Himalayan Database. Nearly 80% of those ascents have been accomplished since 2000. In 2018, a record 807 successful ascents were recorded, according to Arnette's records.

What lives on Everest?

Mount Everest is surrounded by a number of substantial peaks, including Lhotse (27,940 feet, or 8,516 m), Nuptse (25,791 feet, or 7,861 m) and Changtse (24,803 feet, or 7,560 m), according to Britannica.

Those higher altitudes cannot support animal life or vegetation. However, birch, juniper, blue pines, firs, bamboo and rhododendron grow in the lower areas of the mountain, per Britannica. The highest-altitude vascular plant species, a type of herb given the scientific name Saxifraga lychnitis, grows at 21,260 feet (6,480 m) on Everest's slopes and was described in a 2018 paper in the journal Alpine Botany. No known vascular plants grow above this point.

Musk deer, wild yak, red pandas, snow leopards and Himalayan black bears inhabit altitudes below 16,400 feet (5,000 m), according to Britannica. There are also small numbers of Himalayan tahrs, langur monkeys, hares, mountain foxes, martens and Himalayan wolves.

Everest milestones

Here are some other Mount Everest expedition milestones:

• 1895: Andrew Waugh, the British Surveyor General of India, suggests naming the tallest Himalayan peak after his predecessor, Sir George Everest.
• 1921: British explorer George Mallory charts the northern approach.
• May 29, 1953: Tenzing Norgay and Edmund Hillary become the first expedition to officially summit Everest.
• May 20, 1965: Sherpa Nawang Gombu becomes the first person to reach the summit twice, The Guardian reported in a 2011 obituary.
• May 16, 1975: Junko Tabei of Japan becomes the first woman to summit Everest, The New York Times reported that year.
• May 3, 1980: Japanese climber Yasuo Kato is the first non-Sherpa to reach the summit a second time, following his original 1973 summit. (Kato died in 1983 during another attempt to reach Everest's summit, according to a report in the American Alpine Journal.)
• Aug. 20, 1980: Reinhold Messner of Italy is the first person to reach the summit solo, a grueling experience that Messner recounted in a 2003 interview in The Guardian.
• 1996 climbing season: 16 people die while climbing Mount Everest, the most fatalities in a single year up to that point, according to the Indianapolis Public Library. Eight climbers died on May 10 alone, during a storm. One of the survivors, Jon Krakauer, a journalist on assignment for "Outside" magazine, wrote the bestseller "Into Thin Air" (Anchor Books, 1999) about his experience.
• May 22, 2010: Apa Sherpa, who first summited on May 10, 1990, reaches the summit a 20th time, Everest News reported.
• May 23, 2013: At age 80, Japanese climber Minura Yūichirō becomes the oldest person to summit, according to CNN.
• April 25, 2015: The Gorkha earthquake in Nepal triggers an avalanche on Everest, killing 22, the single deadliest day in the mountain's recorded history, Stanford University's Stanford Earth Matters magazine reported.

Additional resources

Explore Mount Everest from the safety and comfort of your home, using this interactive 3D map. Read a harrowing account of two climbers — Reinhold Messner and Peter Habeler — who in 1978 attempted to summit Everest without supplemental oxygen, at PBS' NOVA Online. View highlights from the exhibit "Everest: Ascent to Glory," produced by the Bowers Museum in Santa Ana, California, in a virtual tour.

This article was originally written in 2012 by Live Science contributor Kim Ann Zimmermann, and has since been updated.

A tourist trying to reach his dropped phone took a tumble into Mount Vesuvius this weekend.

The 23-year-old was rescued and treated for minor injuries, according to Sky News, but now faces charges for being on a closed route near the active volcano's summit.

The accident occured on Saturday (July 9), after the young American tourist accidently dropped his phone into the crater at Vesuvius' peak. While scrambling down several meters to reach the phone, the man lost his balance and fell several meters more. According to The Guardian, local guides rappelled down to rescue the man, who was treated for cuts and bruises. A mountain rescue helicopter was also launched to assist. 

Related: Mount Vesuvius didn't kill everyone in Pompeii. Where did the survivors go?

Vesuvius is a stratovolcano towering 4,042 feet (1,232 m) tall. Its crater, formed in a 1944 eruption, is about 1,000 feet (305 m) deep. The mountain is a popular hiking destination, but there are no public trails into the steep-walled crater. The volcano has not experienced any significant eruptions since the  1944 blast, but it is nonetheless closely monitored. More than 700,000 people living in the immediate vicinity would need to be evacuated in the event of a large eruption, and millions more in the port city of Naples and its surroundings would be affected. 

For now, the "Gran Cono" on top of Vesuvius is dangerous not because of imminent eruptions, but due to the effects of gravity. The walls are made up of steep cliffs and volcanic scree, or broken fragments of rocky debris. The crater also hosts active vents that occasionally burp out steam and gas. The rescued tourist and several family members who were with him had taken a route up the mountain that was closed and marked as dangerous, according to The Guardian. All now face charges for invasion of public land. 

Considering the risks of trespassing near the summit of an active volcano, the man was lucky to have escaped with only minor injuries. In 2019, a 32-year-old man was seriously injured after climbing over a barrier around the crater of Hawaii's Kilauea volcano; the ground beneath him crumbled, and he fell 70 feet (21 m). In January, a 75-year-old Hawaiian man was found dead after falling 100 feet (31 m) into the same crater. A similar tragedy occured in 2017 at Solfatara Crater, not far from Vesuvius in Italy, when an 11-year-old boy fell into boiling mud and his parents tried to save him; all three died. 

Vesuvius is most famous for its A.D. 79 eruption that entombed the towns of Herculaneum and Pompeii in a pyroclastic cloud of ash. That eruption killed thousands – the exact death toll is unknown – with a rain of ash and rock, extreme heat, and suffocating clouds of toxic gas.

Originally published on Live Science.  

A striking new satellite image shows the stark contrast between artificial snow and the otherwise arid and rocky mountains being used at the Winter Olympics in Beijing.  

The photo, which was captured by the Landsat 8 satellite on Jan. 29, shows the Yanqing Olympic Zone on Xiaohaituo Mountain, nicknamed "the rock" and located around 46 miles (74 kilometers) northwest of Beijing. The area is being used to stage sliding sports (bobsled, skeleton and luge) and Alpine skiing, all of which require long tracks of snow or ice, which require thousands of cubic feet of snow. However, the region receives an average of only 1.3 inches (3.3 centimeters) of snow in February, according to NASA's Earth Observatory. 

As a result, the Beijing Games, which officially began on Feb. 4, are the first Winter Olympics that will require virtually 100% artificial snow for all snow-based sports, which also include ski jumping, freestyle snowsports and cross-country skiing, according to a new report written by researchers at Loughborough University in England. The use of artificial snow has caused considerable controversy and led to backlash from environmentalists and some of the competing athletes. 

Related: Winter warriors: The fitness skills of 9 Olympic sports

Artificial snow requires an enormous amount of water and energy to produce. In the new report, the researchers estimate that the Beijing Games will use at least 42.4 million cubic feet (1.2 million cubic meters) of artificial snow, which, in turn, will require around 59 million gallons (223 million liters) of water to make. To make that much snow, organizers have installed 300 snow cannons powered by 130 generators that are supplied by eight water cooling towers and three pumping stations.

China has claimed that the Winter Olympics will be powered using 100% renewable energy, according to the BBC.

Artificial snow also poses a number of other environmental issues, according to the report. To maximize the longevity of the fake snow, chemicals are added to the water to help prevent it from melting. These chemicals can cause significant damage to plants covered by the snow, and runoff into rivers can affect nearby areas. The delayed melting of artificial snow can also disrupt plant and animal behavior, and noise pollution created by snow cannons can affect local wildlife, the researchers wrote.

The composition of artificial snow also makes a difference for athletes; it's almost 30% ice and 70% air, whereas natural snow is closer to 10% ice and 90% air, according to the report. This difference makes artificial-snow slopes both faster and physically harder than the natural-snow slopes athletes normally train on, which can trip up even the most experienced athletes, the researchers wrote in the new report. The conditions can also make injuries from accidents more severe.

There have already been a number of high-profile crashes in Alpine skiing in the first few days of the current games. American skier Nina O'Brien suffered compound fractures in her right leg after crashing into the finishing area during the giant slalom. Fellow American and medal-hopeful Mikaela Shiffrin also crashed early in both the giant slalom and slalom races, although she avoided serious injury. And in the men's downhill, German skier Dominik Schwaiger was airlifted to a hospital with a suspected broken left arm after a major wipeout. 

Crashes and major injuries have always been a big risk for Alpine skiers, and none of the injured athletes has directly blamed the artificial surface — but this hasn't stopped fans and commentators from speculating that it may be at least partially responsible. Only after all the races have been finished, will organizers be able to tell exactly how the snow impacted athletes.

However, despite any opposition to artificial snow, climate change could mean more of it at future Winter Olympics. "From the Alps to the Pyrenees, the Rockies to the Andes, snowsports fans are reporting shorter seasons, lower snowfall levels and melting glaciers," researchers wrote in the report.

Originally published on Live Science.

Mountains may look ancient — but some are mere toddlers, while others are great-grandaddies, geologically speaking. So, what is the oldest mountain range? And what about the youngest? 

In general, tall mountain ranges, such as the Himalayas, tend to be young, whereas ranges with shorter peaks from millennia of erosion, like the Appalachians, are often older, according to the American Museum of Natural History in New York City. But due to Earth's ever-changing topography, this superlative is hard to assign — and it demands an understanding of how these peaks rise and fall over time.

Today's landscapes feature actively growing and dormant mountain ranges subjected to billions of years of transformations. That's why pinpointing an age for these peaks gets tricky, said Jim Van Orman, a geochemist at Case Western Reserve University in Ohio. 

Related: Is Mount Everest really the tallest mountain on Earth?

Most mountain ranges form due to tectonic plates, the giant, puzzle-like slabs that glide over Earth's mantle. As different tectonic plates interact over millions of years, entire mountain ranges can surge skyward. 

There are two main types of tectonic boundaries. At convergent boundaries, tectonic plates collide. The impact often causes the less-dense plate to subduct, or go under and into the underlying mantle beneath the other plate. That sinking crust can lift the land above and result in massive mountain ranges, like the Himalayas that house Mount Everest, Van Orman said. Divergent boundaries, on the other hand, occur where tectonic plates separate. As the plates pull away from each other, the crust stretches thin like taffy. Hot magma rises to fill the created gaps, forging mountains and valleys like those in the Basin and Range Province in the western U.S. and northwestern Mexico. 

There's a lot of nuance when it comes to dating mountain ranges. Take the Appalachian Mountains, for example.

The range began rising from a convergent boundary around 470 million years ago and grew even taller starting about 270 million years ago, when the continents that eventually became North America and Africa collided, according to the U.S Geological Survey. Throughout the following millions of years, erosion decimated its original altitude. The mountains we know today are thanks to a later uplift that rejuvenated their elevations. This rise and fall of heights — a trademark characteristic of mountains — make it difficult and subjective to label a range's actual age. 

The Appalachians have "a complicated history," Van Orman told Live Science. "There's the age of the original rocks, but it wasn't a mountain range when it was planed off [or eroded] for a large part of its history. So, how old is it, really?"

While tracing a range's timeline is tricky, geologists do have tools to measure the age of mountains' compositions depending on the type of rock. As igneous and metamorphic rocks form, they generate minerals and radioactive isotopes, or variations of elements that have differing numbers of neutrons in their nuclei, that can be dated. For sedimentary rocks, researchers use clues trapped in the rock layers, such as fossils or volcanic ash, to gauge the rocks' life spans. Eroded mountainous sediments that end up in nearby basins can also be traced back to their peak of origin and dated appropriately, Van Orman said.

From these measurements, geologists can attribute a spectrum of relative ages for some of Earth's mountainous topography. On the older side, the Makhonjwa Mountains in southern Africa, which are just 2,000 to 5,900 feet (600 to 1,800 meters) tall, contain 3.6 billion-year-old rocks, according to NASA's Earth Observatory. Other ancient slabs that make up the cores of continents, called "cratons," may have once been part of mountain ranges and can be found in Greenland, Canada, Australia and beyond. 

Other mountain ranges date to more recent geologic history; for example, those in the Basin and Range Province, such as Snake Range, began to appear around 30 million years ago. Individual volcanic mountains have sprouted within the past million years — some even within the past century, like the volcano Parícutin, which unexpectedly arose from a cornfield during an eruption in 1943, according to the Smithsonian National Museum of Natural History.

Geologists are still researching when and how Earth's various mountain ranges formed. Exploring these elusive timelines could impart insights about past global climate and biodiversity, as these enormous peaks influence air circulation and genetic exchange.

"It helps reconstruct the whole history of Earth," Van Orman said. "Going back deep in time, the only real evidence we have for [plate movement] is looking at these old mountain belts."

Originally published on Live Science.

Twice in our planet's history, colossal mountain ranges that towered as tall as the Himalayas and stretched thousands of miles farther reared their craggy heads out of the Earth, splitting ancient supercontinents in two.

Geologists call them the "supermountains."

"There's nothing like these two supermountains today," Ziyi Zhu, a postdoctoral student at The Australian National University (ANU) in Canberra and lead author of a new study on the mountain majesties, said in a statement. "It's not just their height — if you can imagine the 1,500 miles (2,400 km) long Himalayas repeated three or four times, you get an idea of the scale." 

These prehistoric peaks were more than just an awesome sight; according to new research by Zhu and her colleagues published in the Feb. 15 issue of the journal Earth and Planetary Science Letters, the formation and destruction of these two gargantuan ranges may have also fueled two of the biggest evolutionary boom times in our planet's history — the first appearance of complex cells roughly 2 billion years ago, and the Cambrian explosion of marine life 541 million years ago.

It's likely that, as these enormous mountain ranges eroded, they dumped huge amounts of nutrients into the sea, speeding up energy production and supercharging evolution, the researchers wrote.

Rise of the giants

Mountains rise when Earth's ever-shifting tectonic plates smash two landmasses together, pushing surface rocks to soaring heights. Mountains can grow for hundreds of millions of years or more — but even the loftiest ranges are born with an expiration date, as erosion from wind, water and other forces immediately starts to whittle those peaks away.

Scientists can piece together the history of Earth's mountains by studying the minerals that those peaks leave behind in the planet's crust. Zircon crystals, for example, form under high pressure deep below heavy mountain ranges, and can survive in rocks long after their parent mountains vanish. The precise elemental composition of each zircon grain can reveal the conditions in the crust when and where those crystals formed.

In their new study, the researchers examined zircons with low amounts of lutetium — a rare Earth element that only forms at the base of high mountains. The data revealed two "spikes" of extensive supermountain formation in Earth's history — one lasting from about 2 billion to 1.8 billion years ago, and the second lasting from 650 million to 500 million years ago.

Prior studies had hinted at the existence of that second epic range — known as the Transgondwanan Supermountain, because it crossed the vast supercontinent of Gondwana (a single giant continent that contained the landmasses of modern Africa, South America, Australia, Antarctica, Indian and the Arabian Peninsula). However, the earlier supermountain — called Nuna Supermountain, after an earlier supercontinent — had never been detected before now. 

The distribution of zircon crystals showed that both of these ancient supermountains were enormous — likely spanning more than 5,000 miles (8,000 kilometers) long, or about twice the distance from Florida to California.

That's a lot of rock to erode — and, according to the researchers, that's why these enormous mountains are so important.

Evolution in overdrive

As both mountains eroded away, they would have dumped tremendous amounts of nutrients like iron and phosphorus into the sea through the water cycle, the researchers said. These nutrients could have significantly sped up biological cycles in the ocean, driving evolution to greater complexity. In addition to this nutrient spillover, the eroding mountains may have also released oxygen into the atmosphere, making Earth even more hospitable to complex life.

The formation of the Nuna Supermountain, for example, coincides with the appearance of Earth's very first eukaryotic cells — cells containing a nucleus that eventually evolved into plants, animals and fungi. Meanwhile, the Transgondwanan Supermountain would have been eroding just as another evolutionary boom unfolded in Earth's seas.

"The Transgondwanan Supermountain coincides with the appearance of the first large animals 575 million years ago and the Cambrian explosion 45 million years later, when most animal groups appeared in the fossil record," Zhu said. 

In their research, the team also confirmed previous studies that found mountain formation screeched to a halt on Earth from about 1.7 billion to 750 million years ago. Geologists refer to this period as the "boring billion," because life in Earth's seas seemingly stopped evolving (or at least evolved achingly slowly), Live Science previously reported. Some scientists hypothesize that the lack of new mountain formation may have prevented new nutrients from leaking into the oceans during this time, effectively starving sea creatures and stalling their evolution.

While more research is needed to draw an airtight connection between supermountains and supercharged evolution on Earth, this study seems to confirm that our planet's most productive biological booms occurred in the shadows of some truly colossal mountains. 

Originally published on Live Science.

It's no secret that Mount Everest, the jewel in Nepal's Himalayan crown, is the world's premier mountain. It's one of those facts embedded in childhood, like knowing that Neil Armstrong was the first person to walk on the moon or that blue whales are the largest animals ever to have lived.

You may be surprised to hear, then, that other peaks could conceivably be considered Earth's tallest; it just depends how you measure them.

So, judging by different parameters — including tallest by altitude, tallest from base to top and tallest based on being the farthest point from Earth's center — what is the tallest mountain in the world?

Related: Why don't mountains grow forever?

Mount Everest, located deep in the Mahālangūr Himāl subrange of the Himalayas, is undoubtedly the most famous — and alluring — of all our planet's mountains. Also known as Chomolungma, meaning "Goddess Mother of the World" in Tibetan, Everest was first scaled on May 29, 1953 by Tenzing Norgay, a Sherpa of Nepal, and New Zealander Edmund Hillary, and has since been successfully climbed by around 4,000 people. The mountain has also claimed the lives of over 300 since records started being kept in 1922, according to the Guardian.

Researchers have measured Mount Everest many times over the past few decades, but the latest assessment, announced in November 2021, puts it at 29,031.69 feet (8,848.86 meters) above sea level, which is almost 5.5 miles (8.8 kilometers) tall. It's a pretty impressive height, but it does raise a question: Why do we use "above sea level" when determining the world's tallest peak? 

"In order to have comparability in measurements, it is necessary to have a consistent baseline," Martin Price, a professor and founding director of the Centre for Mountain Studies at the University of Highlands and Islands in Scotland, told Live Science.

"Historically, and even now, elevation is usually given as height above mean sea level," Price told Live Science in an email. "However, this has to be with reference to a standard mean sea level, which has to be defined. Sea levels are different in different parts of the world, and they're changing due to climate change."

As a result, "elevation is now measured in relation to the mathematically defined geoid of the Earth," he said. The geoid is, according to the National Oceanic and Atmospheric Administration, "a model of global mean sea level that is used to measure precise surface elevations." This average is used to ascertain the height of mountains, a process that sometimes requires an aeroplane to fly "back and forth over a mountain in a series of parallel lines to measure how much gravity pulls down on its peak," according to GIM International. These measurements, in conjunction with GPS readings, provide incredibly accurate elevation readings.  

So, all mountains are measured from sea level, predominantly for convenience and consistency, but what if measurements were simply taken from base to peak? Would Everest still top the charts?

The answer is a mountainous "no." That honor would go to Mauna Kea, an inactive volcano in Hawaii. Although its peak is 13,802 feet (4,205 m) above sea level — which is less than half the height of Everest, according to National Geographic — the majority of Mauna Kea is hidden below sea level. When measured from base to peak, Mauna Kea is 33,497 feet (10,211 m) tall, according to the United States Geological Survey, which puts it heads and shoulders above Mount Everest.

Should we, therefore, regard Mauna Kea as the tallest mountain on Earth?

"It all depends on the perspective you take," Price said. "If there were no oceans on our planet, there would be no debate! You could draw comparisons to the highest mountains on other bodies in our solar system, which have no oceans."

Meanwhile, another contender, Mount Chimborazo in Ecuador, boasts a peak that is the farthest point from Earth's center.

Chimborazo isn't the tallest mountain in the Andes — it's not even in the top 30 — but its proximity to the equator is what makes all the difference. Earth is not a perfect sphere — technically, it's an oblate spheroid — and it bulges along the equator. This is a result of the force created by Earth's rotation. As a result, it means there is a difference of 13.29 miles (21.39 km) between the planet's polar radius (3,949.90 miles/6,356.75 km) and its equatorial radius (3,963.19 miles/6,378.14 km), according to the NASA Goddard Space Flight Center.

Chimborazo is just 1 degree south of the equator, where Earth's bulge is most prominent; this geographical quirk means Chimborazo's summit is 3,967 miles from Earth’s core, making it 6,798 feet (2,072 m) farther away from the planet's center than the peak of Everest. 

So, which of these three contenders for tallest mountain should take home first prize?

Mount Everest is the tallest mountain above sea level, while Mauna Kea can certainly claim to be the world's tallest mountain (when sea level isn't taken into account). It would be difficult to make a case for Chimborazo being the tallest, but "it's all a matter of perspective," Price admitted.

Regardless of the mountain you choose, its height will pale in comparison with Mars' Olympus Mons, the largest known volcano in the solar system. It has a height of around 16 miles (25 km), according to NASA, which is almost three times taller than Everest, and a base of 374 miles (601.9 km) in diameter, which is about the same distance separating San Francisco and Los Angeles (383.1 miles/616.5 km).

There is also an impact crater called Rheasilvia on the asteroid Vesta, which is part of the asteroid belt 100 million miles from Earth. At the center of this crater is a peak that scientists believe could be anywhere between 12 and 15.5 miles (20 and 25 km) in height, meaning it may be the tallest mountain in the solar system, according to the NASA Jet Propulsion Laboratory. 

Originally published on Live Science.

Neutron stars are covered with "mountains" only fractions of a millimeter tall, new research shows, meaning these bumps are hundreds of times smaller than previous estimates had suggested.

Neutron stars are compact stellar objects, similar in size to a large city with a diameter of around 6.2 miles (10 kilometers), that weigh at least 1.4 solar masses (1.4 times the weight of the sun). They are born from the explosive deaths of stars that weigh between 10 and 25 solar masses. As a result, they are some of the densest objects in the universe and have an incredibly strong gravitational field, around 2 billion times stronger than Earth's. This extreme gravity squashes neutron stars into near-perfect spheres that are surrounded by a smooth and solid crust. However, deformations in the crust create mountains on the surfaces of these stars, previous research found.

Now, new findings, presented at the National Astronomy Meeting 2021 in the U.K. on July 19, suggest that these mountains are likely to be hundreds of times smaller than scientists previously thought.

Related: 9 epic space discoveries you may have missed in 2020

"They probably should be called 'bumps' or 'hills,' not 'mountains,'" lead researcher Fabian Gittins, a doctoral student at the University of Southampton in the U.K., told Live Science. 

An imperfect sphere 

The crust of a neutron star is a solid layer on the outside of the star, similar to Earth's crust, made out of the nuclei of broken-up heavy elements that contain the ultra-dense soup of neutrons within the star, according to Space.com. It is around 0.6 miles (1 kilometer) thick and is the region of the star with the lowest density, Gittins said. 

Mountains form when the crust is put under enormous amounts of strain and begins to crack. "There are loads of ways [for] these mountains to form," Gittins said. "All that is required is for the star to change its shape."

Possible explanations for the mountain formation include increased strain from its strong electromagnetic field or the fact that they spin more slowly over time. But it may also be caused by a phenomenon known as glitching, in which the star suddenly starts to spin faster, Gittins said.

But regardless of what causes the mountains to form, their size is limited by the amount of strain the crust can take before it breaks. "The stronger the crust is, the larger the mountains it can support," Gittins said.

Smaller than expected 

Gittins and his team predicted the size of neutron star mountains by creating computer models that accurately simulated the crust of a neutron star.

"We subjected these models to a variety of mathematical forces that gave rise to the mountains," Gittins said. "We increased the magnitude of the forces until the crust broke."

This allowed the team to predict the largest possible size of mountains the neutron stars could sustain without breaking. Their new prediction suggests that earlier estimates that pegged these mountains at up to a centimeter tall may have been significantly flawed.

"In looking into this problem, we found that previous studies had technical issues with their approach," Gittins said.

One of the main issues is that previous predictions assumed that the crust of neutron stars was in a shape that strained the crust maximally at every point, but that turned out to be physically impossible, Gittins said. "Our approach did not strain the crust to the maximum at every point but at a single point," he added.

Ripples in space-time 

Neutron stars are known to spin rapidly due to the angular momentum they retain from their exploding parent stars, Gittins said. 

"When a neutron star that is deformed in an asymmetric way is rotating, it causes ripples in the fabric of space-time around it," Gittins said. "These ripples are known as gravitational waves."

Researchers first detected gravitational waves, emanating from two rotating black holes, using the Laser Interferometer Gravitational-wave Observatory (LIGO) in 2015, Live Science previously reported. LIGO has since detected two separate gravitational wave events resulting from the collision of neutron stars, Live Science previously reported, but solitary neutron stars have remained elusive.

"Currently, we haven't been able to detect gravitational waves from rotating neutron stars," Gittins said. But these nondetections also tell scientists a lot about neutron stars, he added.

The smaller the mountains on neutron stars, the smaller the gravitational waves they produce. Therefore, their lack of detection may support Gittins' predictions.

"Given we know the sensitivity of our detectors, we can place upper limits on how large the mountains on neutron stars must be," Gittins said. "The general trend is that the upper limits are getting smaller and smaller."

Therefore, it may be a while before scientists can build detectors big enough to spot the space-time ripples given off by these rapidly rotating microscopic bumps.

The study was first published online Nov. 21, 2020, in the journal Monthly Notices of the Royal Astronomical Society.

Originally published on Live Science.

Last week, wildlife officials in Utah yeeted thousands of fish out of a plane and into 200 high-elevation lakes across the state.

The Utah Division of Wildlife Resources (DWR) has been dumping fish out of airplanes since 1956, Live Science previously reported. In a video that went viral this week, fish can be seen bursting from the underside of a plane, carried downwards in a plume of water; the shiny animals then careen through the air towards the water's surface. The most common species dropped during these flights are various species of trout, a hybrid trout known as splake (Salvelinus fontinalis) and Arctic grayling (Thymallus arcticus), according to Live Science.

Related: 5 surprising facts about lakes 

Although this method of restocking lakes may seem violent for the young fish, because the creatures are only 1 to 3 inches (2.5 to 7.6 centimeters) long at the time of release, the wind actually carries them down quite gently — like leaves fluttering in a breeze, Phil Tuttle, the outreach manager for the southern region office of the Utah DWR, told Live Science in 2018. About 95% of the fish are expected to survive each release. 

During a single flight, the plane carries hundreds of pounds of water and can drop up to 35,000 fish, Utah DWR officials wrote on Facebook. Pilots fly just above the tree line while dropping the fish, or as low as possible while considering other natural barriers like cliffs and mountains, Live Science previously reported. Before the Utah DWR began using planes, people and horses would carry the fish up to the remote mountain lakes on foot; this journey proved more stressful for fish than being tossed from a zooming plane.

If the Utah DWR didn't restock its high-elevation lakes each year, the popular fishing spots would soon be entirely depleted of fish. The fish used for restocking are raised in hatcheries, and most are bred to be sterile to prevent a sudden population boom and ensure they have a minimal impact on native wildlife species.

Originally published on Live Science.

Earth, like so many of its human inhabitants, may have experienced a mid-life crisis that culminated in baldness. But it wasn't a receding hairline our planet had to worry about; it was a receding skyline.

For nearly a billion years during our planet's "middle age" (1.8 billion to 0.8 billion years ago), Earth's mountains literally stopped growing, while erosion wore down existing peaks to stumps, according to a study published Feb. 11 in the journal Science.

This extreme mountain-forming hiatus — which resulted from a persistent thinning of Earth's continental crust — coincided with a particularly bleak eon that geologist's call the "boring billion," the researchers wrote. Just as Earth's mountains failed to grow, the simple life-forms in Earth's oceans also failed to evolve (or at least, they evolved incredibly slowly) for a billion years.

Related: Why don't mountains grow forever?

According to lead study author Ming Tang, the mountain of trouble on Earth's continents may have been partially responsible for the slow going in Earth's seas.

"Continents were mountainless in the middle age," Tang, an assistant professor at Peking University in Beijing, China, told Live Science in an email. "Flatter continents may have reduced nutrient supply [to the ocean] and hindered the emergence of complex life."

When mountains vanish

At the convergent boundaries where Earth's continental plates clash, mountains soar upward in a process called orogenesis. The continental crust at these boundaries is thicker on average and buoyed by magma, lifting surface rocks up to dizzying heights. Meanwhile, erosion and gravity push back against the peaks; when the tectonic and magmatic processes below the surface stop, erosion wins out, whittling mountains away.

Because even the mightiest mountains disappear over time, studying ancient Earth's crustal thickness can be the best way to gauge how actively mountains formed in the past. To do that, the study authors analyzed the changing composition of zircon minerals that crystallized in the crust billions of years ago.

Today, tiny grains of zircon are easily found in sedimentary rocks all over the planet's surface. The precise elemental composition of each grain can reveal the conditions in the crust where those minerals first crystallized, eons ago.

"Thicker crust forms higher mountains," Tang said. Crustal thickness controls the pressure at which magma changes composition, which then gets recorded by anomalies in zircons crystallizing from that magma, he added.

In a previous study published in January in the journal Geology, Tang and colleagues found that the amount of europium embedded in zircon crystals could reveal crust thickness at the time those crystals formed. More europium signifies higher pressure placed on the crystal, which signifies thicker crust above it, the researchers found.

Now, in their new study in Science, the researchers analyzed zircon crystals from every content, and then used those europium anomalies to construct a history of continental thickness going back billions of years. They found that "the average thickness of active continental crust varied on billion-year timescales," the researchers wrote, with the thickest crust forming in the Archaean eon (4 billion to 2.5 billion years ago) and the Phanerozoic (540 million years ago to the present).

Right between those active mountain-forming eras, crustal thickness plummeted through the Proterozoic eon (2.5 billion to 0.5 billion years ago), reaching a low during Earth's "middle age."

The eon of nothing

It may not be a coincidence that Earth's flattest eon on land was also its most "boring" eon at sea, Tang said.

"It is widely recognized by our community that life evolution was extremely slow between 1.8-0.8 billion years ago," Tang told Live Science. "Although eukaryotes emerged 1.7 billion years ago, they only rose to dominance some 0.8 billion years ago."

By contrast, Tang said, the Cambrian explosion, which occurred just 300 million years later, introduced almost all major animal groups that we see today. For whatever reason, life evolved achingly slowly during the "boring billion," then jump-started just as the crust began thickening. 

What's the correlation? If no new mountains formed during this period, then no new nutrients were introduced to Earth's surface from the mantle below, the researchers wrote — and a dearth of nutrients on land also meant a dearth of nutrients making their way into the ocean through the water cycle. As mountain forming stalled for a billion years, a "famine" of phosphorus and other essential elements could have starved Earth's simple sea critters, limited their productivity and stalled their evolution, the team suggests.

Life, and mountains, eventually flourished again when the supercontinent Nuna-Rodinia broke apart at the end of the Proterozoic eon. But before then, this gargantuan continent may have been so massive that it effectively altered the structure of the mantle below, stalling plate tectonics during the "boring billion" and resulting in an eon of crustal thinning, the researchers wrote. But further research is needed to fully solve the mystery of Earth's vanishing mountains.

Originally published on Live Science.

Mount Everest is the tallest mountain in the world — but sometimes, it feels like the second-tallest, according to a story reported in the American Geophysical Union's news blog Eos.

That's because the mountain's air pressure fluctuates significantly throughout the year, a recent study found, causing the summit's "perceived elevation" to occasionally dip below that of its less-lofty rival, K2 — the second-tallest mountain in the world.

"Sometimes K2 is higher than Everest," lead study author Tom Matthews, a climate scientist at Loughborough University in the United Kingdom, told Eos.

Related: In photos: Mount Everest expeditions then and now

In the new study, published Dec. 18 in the journal iScience, Matthews and his colleagues looked at more than 40 years of air pressure data recorded by both weather stations near the summit of Mount Everest and the European Space Agency's Copernicus satellite.

Air pressure is closely tied to oxygen availability on Everest; when air pressure decreases, there are fewer oxygen molecules in the air, making the simple act of breathing much more strenuous, according to Eos. For this reason, many who choose to hike Everest rely on supplemental oxygen to stay on their feet as they scale to higher elevations where the air is thinner. (Only 169 men and eight women have ever summited Everest without the use of supplemental oxygen, the study authors noted.)

But while air pressure reliably decreases with elevation, it also fluctuates with the weather, the study authors found. From 1979 to 2019, the air pressure near the peak of Everest ranged anywhere from 309 to 343 hectopascals — roughly one-third the pressure at sea level — depending on the season.

"Compared with the average air pressure measured on Everest in May, that span translates into a 737-meter [2,417 feet] difference in how high the summit feels from an oxygen availability standpoint," science journalist Katherine Kornei wrote in the blog.

Put another way, sometimes the oxygen availability on Everest makes the mountain feel thousands of feet shorter than it really is. Occasionally, the 29,000-foot-tall (8,800 m) mountain feels shorter (to our bodies) than the world's next tallest mountain, K2, which measures 28,250 feet (8,600 m) tall.

The researchers also found that air pressure on Everest was consistently highest in the summertime, making that the best season to scale the mountain based purely on oxygen availability. As Earth's atmosphere continues to warm due to climate change, there could even be a permanent decrease in the mountain's perceived elevation, the researchers found.

"Warming will shrink the mountain a little bit," Matthews told Eos.

Read the whole story on the Eos website.

Originally published on Live Science.

The Swiss Alps are going through a growth spurt, according to a new study suggesting that part of the mountain range is lifting upward faster than it is eroding.

The finding goes against the conclusions of two previous studies, which suggested that the Alps were neither growing nor shrinking.

However, an international team of researchers has now found that isn't the case, after analyzing different isotopes, or versions of an element, in the sand from hundreds of rivers in the European Alps. One particular isotope — beryllium-10 (10Be) — revealed information about erosion rates in different parts of the Alps, the team said.

Related: In photos: The vanishing glaciers of Europe's Alps 

The isotope 10Be is formed in part when cosmic rays, or fragments of atoms such as protons, electrons and charged nuclei, stream through Earth's atmosphere and reach the planet's surface. When those cosmic rays hit the ground, say in the rocky Alps, they kick off a nuclear reaction in the oxygen atoms in quartz, which forms 10Be.

This isotope accumulates only on Earth's uppermost surface, which means scientists can determine a surface's age by measuring the levels of 10Be in sediment that's been around for least a few millennia. Quartz grains with high concentration of 10Be were likely exposed to cosmic rays for a very long period. In contrast, samples with low concentrations of 10Be are much younger.

"This principle can also be used to quantify the rate of erosion in the Alps, averaged over a few thousand years," study co-author Fritz Schlunegger, a geologist at the Institute of Geological Sciences at the University of Bern in Switzerland, said in a statement. In the Alps, rocky grains containing 10Be get washed away into mountain streams and rivers, which carry it to the plains. So, if lots of fairly low-concentration 10Be is found in riverbeds, that suggests more recent sediment and in turn that the mountains are eroding fairly fast.

In the study, the researchers did a massive sweep of quartz grains from more than 350 rivers running through the Alps. "With this strategy, we can for the first time draw a picture of the erosion across the entire European Alps and explore its driving mechanisms," study first author Romain Delunel, a geologist at the Institute of Geological Sciences at the University of Bern in Switzerland, said in the statement.

Rising skyward

The Alps aren't changing height uniformly, however. In some places, the range is wasting away. For instance, in Valais, a canton (state) in southern Switzerland, the Alps are shrinking, with an erosion rate of nearly 25 feet (7.5 meters) per millennium. The mountainous region with the slowest erosion rate, in eastern Switzerland by the Thur River, eroded just 0.5 inches (1.4 centimeters) per 1,000 years. 

"This erosion rate is very low, almost boring," Schlunegger said. 

But the Central Alps are growing, thanks to uplift that outpaces erosion. "This is a big surprise, because until now we have assumed that uplift and erosion were in equilibrium," Schlunegger said. To put a number on it, that region of the Alps is growing about 31 inches (80 cm) every millennium, after accounting for erosion, the researchers found. "This means that the Central Alps are still growing, and surprisingly quickly," Schlunegger said. 

Meanwhile, erosion and uplift are in balance in the Western Alps, and erosion is faster than uplift in the Eastern Alps.

So, why is erosion happening in certain parts of the Alps, but not others? Rain and snow don't have a measurable effect on erosion, but the slope and topography of a mountain do. Many of these rock faces were carved by the last major glaciations, the researchers found. Furthermore, "very steep landscapes" don't lead to increased erosion, Delunel said. "That was another surprise because we thought that very steep terrain would be eroded very quickly. We don't yet fully know why this is not the case and therefore see a need for further research."

The study was published in the December issue of the journal Earth-Science Reviews.

Originally published on Live Science.

Archaeologists recently documented a rare treasure trove of Viking Age objects littering a long-forgotten mountain pass, including the remains of a dog wearing its collar and leash.

As climate change melts Norway's glaciers, pockets of history hidden for centuries or millennia are finally seeing the light of day. Melting along a high-altitude trail in the Lendbreen glacier has revealed hundreds of artifacts dating to the Viking Age, the Roman Iron Age and even the Bronze Age.

Remarkably well-preserved items littered the winding path, including clothing and shoes, a variety of tools and riding gear, and animal bones and dung. They offer clues about daily life, and hint at the challenges and importance of mountain travel in this region, according to a new study published online April 16 in the journal Antiquity.

Related: Fierce fighters: 7 secrets of Viking seamen

"A lost mountain pass is a dream discovery for us glacial archaeologists," lead study author Lars Pilø, co-director of the Glacier Archaeology Program (GAP), said in a statement. A collaboration between the Innlandet County Council and the Museum of Cultural History at the University of Oslo in Norway, GAP recovers and identifies historical artifacts exposed by disappearing Norwegian glaciers. 

The ice patch at the Lendbreen site extends from about 5,500 to 6,300 feet (1,690 to 1,920 meters) above sea level, and the mountain pass rises to nearly 6,500 feet (1,973 m) above sea level, researchers reported. Melt at Lendbreen in 2011 revealed the first evidence of the long-hidden trail, with cairns (human-made piles of stone) marking the route and a shelter at the highest point. 

In the new study, scientists documented discoveries that appeared between 2011 and 2015, preserved by the dry, frozen climate and protected by layers of ice (before being exposed). Among the objects were shoes made of hide; a woven mitten and more than 50 pieces of fabric; a walking stick inscribed with runes; a wood-handled knife; horseshoes and sled pieces; and bones from pack horses.

"The preservation of the objects emerging from the ice is just stunning," study co-author Espen Finstad, an archaeologist with the Department of Cultural Heritage in Lillehammer, Norway, said in the statement.  

Dead animals and broken tools were likely abandoned along the path by the travelers, while tools in good condition may have simply been lost, according to the study. The presence of usable clothing among the discarded objects is more puzzling, but these items may have been thrown away by people who were suffering from severe hypothermia, which can cause irrational behavior, the researchers wrote.

Carbon dating of approximately 60 objects indicated that the pass was actively used from around A.D. 300 to A.D. 1500. Some objects, such as a ski and an arrow, dated to the Bronze Age (1750 B.C. to 500 B.C.), and several artifacts were even older. But the items that were most abundant dated to around A.D. 1000 — the Viking Age — suggesting that the mountain pass was busiest during this period. 

Related: Photos: Vikings accessorized with tiny metal dragons

Unlike many other ancient mountain passes that are known from the Alps and the Himalayas, this route was likely busiest when snow and ice were abundant, as the route would have been difficult for pack animals and sleds to navigate when rocks were bare, according to the study. 

By sifting through the objects, scientists reconstructed how people used the path and how that changed over time. What was once a high-traffic roadway during the Viking Age waned in popularity and was all but abandoned by the 16th century, possibly due to climate change-related melting, economic upheaval and the arrival of pandemics from Europe, the researchers wrote.

Another substantial melt event at Lendbreen in 2019 revealed even more intriguing artifacts that are yet to be scientifically described, including the leashed dog remains, "and a wooden box with the lid still on," Finstad said.

• Photos: A man, a horse and a dog found in Viking boat burial
• Photos: 10th-century Viking tomb unearthed in Denmark
• Image gallery: Viking voyage discovered

Originally published on Live Science.

Imagine a world where mountains grow so high, they poke through the upper atmosphere and create a rocky maze for pilots to navigate.

Maybe that world exists somewhere in the far reaches of the universe. But on Earth, mountains can't grow much higher than Mount Everest, which extends 29,029 feet (8,840 meters) above sea level. 

So what stops our planet's mountains from growing … forever?

There are two major factors that limit mountains' growth, said Nadine McQuarrie, a professor in the department of geology and environmental science at the University of Pittsburgh.

The first limiting factor is gravity. Many mountains form because of movements in Earth's surface layer known as plate tectonics; this theory describes the Earth's crust as mobile and dynamic, divided into large pieces that inch around with time. When two plates collide, the impact forces material from their touching edges to move upward. This is how the Himalayas mountain range in Asia, which includes Mount Everest, formed.

Related: Which Mountain Is the Tallest in the World?

The plates keep pushing together and the mountains keep growing, until it becomes "too hard to do that work against gravity," McQuarrie told Live Science. At some point the mountain becomes too heavy, and its own mass stops the upward growth caused by the crunching of those two plates. 

But mountains can also form in other ways. Volcanic mountains, like those of the Hawaiian Islands, for example, form from molten rock that erupts through the planet's crust and begins piling up. But no matter how mountains are formed, they eventually become too heavy and succumb to gravity, McQuarrie said. 

In other words, if Earth had less gravity, its mountains would grow higher. That is indeed what happened on Mars, where mountains loom much taller than on our planet, McQuarrie added. Mars' Olympus Mons, the tallest known volcano in the solar system, extends 82,020 feet (25,000 m) high, nearly three times taller than Mount Everest. 

Most likely because Mars has low gravity and high eruption rates, mountain-building lava flows continued on Mars for much longer than they ever have (or ever will) on Earth, according to NASA. What's more, Mars' crust isn't divided up into plates like that of our planet. On Earth, as plates move around and over hotspots — areas of the mantle that shoot out hot plumes — new volcanoes form and existing volcanoes become extinct. Activity in Earth's mantle distributes lava  across a larger region, forming multiple volcanoes. On Mars, the crust doesn't move so the lava piles up into a single, massive volcano. 

The second limiting factor for mountain growth on Earth is rivers. At first, rivers make mountains appear taller — they carve into the edges of the mountains and erode material, creating deep crevices near a mountain's base. "All of these really high, beautiful, dramatic peaks are actually a little bit lower than the plateau itself," McQuarrie said. But as rivers erode material, their channels may become too steep. This can trigger landslides that carry material away from the mountain and limit its growth, she added. 

A group of researchers recently suggested that rivers reach a "threshold steepness" after which their impact on a mountain's growth through erosion is limited in a study published Sept.16 in the journal Nature Geoscience. 

Underwater mountains are similarly limited by gravity and landslides but they can get much taller than the mountains on land can because the higher-density water supports them against gravity more than air does, McQuarrie said. "Water provides lateral support to the sides of these mountain ranges allowing them to be higher," she said.

Everest is often referred to as Earth's highest summit, but there are other contenders for the "world's tallest mountain" title. Mauna Kea, an inactive volcano in Hawaii, is the world's tallest mountain if measured from its base — which sits deep in the Pacific Ocean — to its summit. It measures 33,500 feet (10,210 m), a little bit taller than Everest. But Mauna Kea's base is 19,700 feet (6,000 m) below sea level and its peak is at 13,796 feet (4,205 m) above sea level. When measuring from sea level, Mount Everest is over two times taller than Mauna Kea, and Everest's peak is the highest point in the world.

• What Will Happen to Earth When the Sun Dies?
• Why Does Earth Have an Atmosphere?
• How Is Earth's Age Calculated?

Originally published on Live Science.

Melting glaciers are revealing dozens of dead bodies on the world's tallest mountain, according to news reports.

The treacherous journey to the summit of Mount Everest is riddled with obstacles — falling ice, ragged terrain, biting temperatures and incredible heights that cause altitude sickness. While nearly 5,000 people have successfully climbed the mountain, another 300 are thought to have died along the way. [The World's Tallest Mountains]

Some of these bodies ended up covered in ice and remained hidden that way for many years. But now, climate change is accelerating the ice melt around them, exposing multiple limbs and bodies, the BBC reported March 21.

Indeed, last year, a group of researchers found that the ice on Everest was warmer than average, and a study conducted four years ago found that ponds on the mountain were expanding with melting ice water, according to the BBC. But it’s not only melting glaciers that are exposing these bodies — it’s also the movement of the Khumbu Glacier in Nepal.

Most of the dead bodies are turning up at the Khumbu Icefall, one of the most dangerous spots on the mountain. There, blocks of ice can unexpectedly collapse and glaciers can slip several feet downhill per day, the Washington Post reported in 2015. In 2014, 16 climbers were killed at once in that area, crushed under falling ice.

Removing bodies from the mountain is a delicate, dangerous and extremely costly task riddled with legal constraints. Nepal’s law, for example, requires government agencies to be involved when dealing with them, according to the BBC.

What’s more, "most climbers like to be left on the mountains if they died" there, Alan Arnette, a mountaineer told the BBC.

• Infographic: Tallest Mountain to Deepest Ocean Trench
• Andes: World’s Longest Mountain Range
• Image Gallery: Hiking the Himalayas

Originally published on Live Science.

Earth's continents may have been born under large mountain ranges like the Andes.

New research combining a mysterious missing trace element, a 66-million-year-old rock burped up by an ancient volcano, and a database of all the rock chemistry analyzed by scientists in the past century explains why Earth has continents. Published Jan. 16 in the journal Nature Communications, the study suggests that where mountains are born, so are continents.

"It's like a jigsaw puzzle," said study leader Ming Tang, a postdoctoral researcher in geology at Rice University in Houston. "There is a missing part in this continental jigsaw puzzle, and it seems that we found the answer." [Photo Timeline: How the Earth Formed]

The missing piece

The missing piece is a rare-earth metal called niobium. In Earth's middle layer, called the mantle, as well as in the oceanic crust (the part of the planet’s outer layer covered by seas), niobium and another rare-earth element, tantalum, typically co-occur in a consistent ratio. The continental crust is weird, Tang told Live Science. The crust that makes up the continents is relatively low in niobium.

The case of that missing niobium in the continental crust has pestered geoscientists for decades. Tang went hunting for it in a rock geochemistry database maintained by the Max Planck Institute in Germany. He searched subduction zones, where the crust grinds into the mantle and magmas form. That magma, when cooled, has the potential to create continents. Niobium wasn't missing across many of these subduction zones, Tang found. But it was bizarrely absent in particular mountain-building regions like the Andes.

The Andes are a massive mountain-building region, powered by the nearby tectonics of a subduction zone. As the oceanic crust off the coast of South America crunches below the continental crust, the restless Andes rise, and magma spews from some of the highest-elevation volcanoes on Earth, Tang said.

Regions like the Andes — which form atop a subduction zone — are known as continental arcs, and they're special because the crust there is about twice as thick as regular continental crust, Tang said. Unfortunately, the chemistry of the rocks at the bottom of this crust are a mystery. At nearly 50 miles (80 kilometers) below the surface, these rocks are inaccessible.

Enter the xenolith

Fortunately, the Sierra Nevada mountains of the western United States used to be an active mountain-building region, like the Andes today. Tang, along with Rice University petrologist Cin-Ty Lee, and their colleagues analyzed a sample of rock that formed some 66 million years ago and was pushed to the surface in a volcanic eruption about 25 million years ago. This rock, called a xenolith, originally formed deep at the base of the Sierra Nevada when they were an active continental arc — the researchers found the rock in Arizona.

The rock "might provide a very nice, excellent analog to the deep crust beneath the Andes," Tang said.

The analysis showed that the continental arc xenolith had extra niobium. Tang and his colleagues had found the continent's missing rare-earth element: The lost niobium is stuck at the bottom of continental arcs.

Niobium gets trapped so deep because of the unique conditions beneath these super-thick sections of Earth's crust. Under continental arcs, because of the thick crust, the mantle is under high pressure, Tang said. Under high pressure, a titanium mineral called rutile crystallizes out of magma. Rutile happens to trap large amounts of niobium, and not much tantalum. It's also very dense, so it falls deep within the crust as other rocks get circulated toward the surface.

Because the continental crust is missing niobium, it must have formed under these continental- arc conditions, Tang said. And that means that places like the Andes probably held the seed of all the continents on Earth today.

"Every piece of continent that we are standing on right now probably started out with these mountain-building processes," Tang said.

• Photos: The World's Tallest Mountains
• Images: Antarctic Odyssey - The Majestic Transantarctic Mountains
• In Photos: Ocean Hidden Beneath Earth's Surface

Originally published on Live Science.

Far from a process of smooth, inevitable ascendance, the formation of the iconic Andes Mountains was downright explosive. As the peaks rose skyward along the western coast of South America dozens of millions of years ago, violent volcanic activity rocked the continent , a new study finds.

Researchers made the discovery by studying the buried remnants of the continent's tectonic plates. And what the scientists found surprised them.

The 4,300-mile-long (7,000 kilometers) Andes — the longest continuous mountain range in the world — didn't form in the way that scientists had long thought. Previously, geologists held that the Nazca oceanic plate, which lies under the eastern Pacific Ocean, had steadily and continuously subducted (slipped under) South America, which made the ground rise and eventually create the towering Andes. [Photos: The World's Tallest Mountains]

"The Andes Mountain formation has long been a paradigm of plate tectonics," study co-author Jonny Wu, assistant professor of geology at the University of Houston, said in a statement.

But after studying the underground remnants of the Nazca oceanic plate, which sit about 900 miles (1,500 km) underground, the researchers learned that the plate did not go through a steady and continuous subduction. Rather, the Nazca plate was at times torn away from the Andean margin (the place where it was subducting), which led to volcanic activity, the researchers said.

To double-check their work, the scientists modeled volcanic activity along this margin.

"We were able to test this model by looking at the pattern of over 14,000 volcanic records along the Andes," some of which date back to the Cretaceous, Wu said.

Underground clues

The remains of the subducted Nazca plate are far underground, so how did the scientists study them?

When tectonic plates move underground — that is, when they creep under Earth's crust and enter the mantle — they sink toward the core, much like fallen leaves sinking to the bottom of a lake. But these sinking plates retain some of their shape, offering clues to what the Earth's surface looked like millions of years ago. In the case of the Nazca plate, more than 3,400 miles (5,500 km) of lithosphere, the outer, rigid part of the crust and upper mantle, was lost to the mantle, the researchers said.

Scientists can image these plates using data collected from earthquake waves, much like a computed tomography (CT) scan allows doctors to see the insides of a patient.

"We have attempted to go back in time with more accuracy than anyone has ever done before. This has resulted in more detail than previously thought possible," Wu said. "We've managed to go back to the age of the dinosaurs."

In the case of this study, after analyzing these underground tectonic leftovers, the researchers were able to piece together how the Andes formed. The subducting Nazca plate slammed into a transition zone, or a discontinuous layer in the mantle, which slowed the plate’s movement and caused buildup above it, the researchers said in the statement.

Their model suggests that the currents phase of the Nazca subduction began in what is now Peru, during the late Cretaceous period, about 80 million years ago, the researchers wrote in the study. Then, the subduction moved southward, reaching the southern Andes in Chile by the early Cenozoic, about 55 million years ago, they said.

"Thus, contrary to the current paradigm, Nazca subduction has not been fully continuous since the Mesozoic but instead included episodic divergent phases," the researchers wrote in the study.

The study was published online today (Jan. 23) in the journal Nature.

• Photos: Journey into the Tropical Andes
• Granite Photos: Bedrock of the Earth
• 10 Most Hazardous Countries for Volcanoes (Photos)

Originally published on Live Science.

Since then, the land has healed and recovered much of its natural beauty, but it's likely Mount St. Helens won't stay quiet forever. [Striking Images of Mount St. Helens Before, After and Now]

Geologic records suggest the volcano has gone through several stages of activity, according to the U.S. Geological Survey (USGS). Since at least 1800, the volcano experienced a period of intermittent eruptions until 1857, then a few minor, steam-driven eruptions in 1998, 1903 and 1921. Otherwise, the volcano remained relatively peaceful throughout the 20th century and was a popular recreational area until its 1980 eruption.

On shaky ground

On March 1, 1980, the University of Washington installed a new system of seismographs to monitor earthquake activity in the Cascades, especially around Mount St. Helens, where there had been a recent increase in seismic activity. According to the Department of Geological Sciences at San Diego State University, the first key indication that major volcanic activity was imminent was when a 4.2-magnitude earthquake rumbled below Mount St. Helens on March 20.

Just three days later, on March 23, a 4.0-magnitude earthquake shook the ground and set off a chain of smaller-magnitude earthquakes — about 15 per hour. The shaking continued and began to intensify over the next couple of days. By March 25, seismographs were detecting an average of three, 4.0-magnitude quakes every hour. Aerial observations revealed new fractures in the surrounding glaciers and numerous rockslides.

Around noon local time on March 27, tension was released as the peak of Mount St. Helens burst open, shooting steam 6,000 feet (1,829 meters) into the air and blasting a 250 foot-wide crater (75 meter) through the summit, according to USGS.

Smaller eruptions continued at a rate of about one per hour throughout March, then decreased to about one per day in April until they stopped on April 22. On May 7, eruptions started back up again, and the rate of eruptions gradually increased for the next 10 days. By May 17, the north side of the volcano had bulged out about 450 feet (140 m) nearly horizontally, indicating that magma was rising toward the summit of the volcano and pressure was building.

"This is it!"

On the morning of May 18, USGS volcanologist David Johnston, woke up at his campsite on a ridge 6 miles north of the volcano, and radioed in his regular 7 a.m. report. The changes to the bulging mountain were consistent with what had been reported several times daily since the watch began and left no indication of what was about to happen, according to USGS.

At 8:32 a.m., a magnitude-5.1 earthquake registered on the seismographic equipment about 1 mile beneath the volcano. His excited radio message, "This is it!" was followed by a stream of data. It was his last transmission; the ridge he camped on was within the direct blast zone. [Gallery: The Incredible Eruption of Mount St. Helens]

Overhead, Keith and Dorothy Stoffel were making an aerial survey of the volcano when they noticed a landslide on the lip of the summit's crater, USGS reported. Within seconds, the whole north face of the mountain was on the move. Just as they passed around to the east side of the mountain, the north face collapsed, releasing superheated gases and trapped magma in a massive lateral explosion. Keith put the plane into a steep dive to gain the speed to outrun the cloud of incandescent gas; Dorothy continued to photograph the eruption through the rear windows of the plane as they made their escape.  

The abrupt release of pressure over the magma chamber created a “nuée ardente,” a glowing cloud of superheated gas and rock debris blown out of the mountain face moving at nearly supersonic speeds. Everything within eight miles of the blast was wiped out almost instantly, according to USGS. The shockwave rolled over the forest for another 19 miles, leveling century-old trees; all the trunks neatly aligned to the north. Beyond this “tree down zone” the forest remained standing but was seared lifeless. The area devastated by the direct blast force covered an area of nearly 230 square miles (596 square kilometers).

Shortly after the lateral blast, a second, vertical explosion occurred at the summit of the volcano, sending a mushroom cloud of ash and gases more than 12 miles (19 km) into the air. Over the next few days, an estimated 540 million tons (490,000 kilotons) of ash drifted up to 2,200 square miles (5,700 square km), settling over seven states.

The heat of the initial eruption melted and eroded the glacial ice and snow around the remaining part of the volcano. The water mixed with dirt and debris to create lahars, or volcanic mudflows. According to USGS, the lahars reached speeds of 90 mph (145 km/h), and demolished everything in their path. Most of the glaciers surrounding Mount St. Helens melted, too, and likely contributed to the destructive lahars, Benjamin Edwards, volcanologist and professor of Earth Science at Dickinson College in Pennsylvania, told Live Science in an email.

Most destructive U.S. volcano

The 1980 Mount St. Helens eruption was the most destructive in U.S. history. Fifty-seven people died, and thousands of animals were killed, according to USGS. More than 200 homes were destroyed, and more than 185 miles of roads and 15 miles of railways were damaged. Ash clogged sewage systems, damaged cars and buildings, and temporarily shut down air traffic over the Northwest. The International Trade Commission estimated damages to timber, civil works and agriculture to be $1.1 billion. Congress approved $950 million in emergency funds to the Army Corps of Engineers, the Federal Emergency Management Agency and the Small Business Administration to help with recovery efforts.

Will Mount St. Helens erupt again?

Today, scientists keep a close watch on Mount St. Helens and other volcanoes in the Pacific Northwest. The volcano's location on the Cascadian Subduction Zone means another eruption is inevitable, Howard R. Feldman, chair of geology and environmental science at Touro College in New York, told Live Science.

But predicting when that will happen is extremely difficult.

Long-term seismic data is key to knowing when a volcano might be on the verge of erupting, Edwards said. A jump in the number of earthquakes over the course of a week, or even a day, can signal the start of new activity.

For the last few years, the seismic activity going on around Mount St. Helens has fallen within the normal range, as data from the Pacific Northwest Seismic Network suggest.

This article was updated on October 16, 2018, by Live Science Contributor, Rachel Ross.

Kilauea is one of the world’s most active volcanoes. It is a shield-type volcano that makes up the southeastern side of the Big Island of Hawaii. The volcano rises 4,190 feet (1,227 meters) above sea level and is about 14 percent of the land area of the Big Island. The summit caldera contains a lava lake known as Halema`uma`u that is said to be the home of the Hawaiian volcano goddess, Pele.

To the casual observer, Kilauea appears to be part of the larger volcano Mauna Loa, but geological data indicates that it is a separate volcano with its own vent and conduit system. Kilauea has had more than 60 recorded eruptions in the current cycle, according to the U.S. Geological Survey, and has been erupting on a continuous basis since 1983.

On May 3, 2018, the volcano erupted dramatically, several hours after a magnitude-5.0 quake struck the Big Island. The eruption spewed lava into residential subdivisions in the Puna district of the Big Island, prompting mandatory evacuations of the Leilani Estates and Lanipuna Gardens subdivisions, the Honolulu Star-Advertiser reported.

Formation theories

Scientists have two theories about the formation of the Hawaiian Islands. Unlike most volcanoes, the Hawaiian chain sits squarely in the middle of the Pacific plate rather than on a tectonic boundary. In 1963, J. Tuzo Wilson proposed the “hotspot theory” to explain this unusual placement. Wilson proposed that the linear geography of the Hawaiian Islands is due to the movement of the Pacific plate over a stationary point of great heat from deep within the Earth..

Heat from this localized hotspot melts the Pacific plate above the hotspot as the rocky crust is pushed over it by the spreading seafloor along the plate boundary. The melting rock of the Pacific plate produces magma. Less dense than the solid rock of the plate, the magma rises through the mantle and the crust as a thin thermal plume, erupting beneath the ocean to form an active seamount. Over time, the countless eruptions increase the height of the seamount until it breaks the ocean surface and becomes an island volcano.

As the Pacific plate continues to move northward over time, the island is pushed away from the hotspot and a new island begins to form over the hotspot. In 2009, Cecily Wolfe of the University of Hawaii used sea bottom sensors to identify how seismic waves propagate through the pliable mantle layer beneath the Earth’s crust. She believes her evidence has pinpointed the location of the hotspot.

In contrast, a new study done by geologists from MIT and Purdue University in 2011, mapped rock layers within the crust. They could find no evidence of a single thermal plume. Instead, they found a “pancake shaped” layer of abnormally hot rock in the crust only about 403 miles beneath the surface, well above the mantle. Temperatures were 300 to 400 degrees C (572 to 752 F) hotter than expected at that depth. This data suggests that hotspots may not be as deep as previously thought and may not be permanently fixed in one spot. Wolfe acknowledges the importance of the new find, but believes it will take much more work to truly explain how her thermal plume and the “pancake” of hot rocks are related and how they provide the heat source for Kilauea and the other active volcanoes of the Hawaiian Islands. “Neither theory is rock solid. Nothing in earth science is perfect,” Wolfe observed.

Eruption history

Native Hawaiian oral traditions record the extraordinary eruptive history of Kilauea long before European and American missionaries wrote about it in their journals. Scientific study of the volcano began when geologist Thomas Jagger of the Massachusetts Institute of Technology visited Hawaii on a lecture tour and was approached by local businessmen. The Hawaiian Volcano Research Association (HVRA) was formed in 1909. In 1919, Jagger convinced the National Weather Service to take over the pioneering research, and in 1924 the observatory was taken over by the U.S. Geological Survey.

The current ongoing eruption cycle began on Jan. 3, 1983, along the middle of the east rift zone. By April, the eruptions became localized at one vent. Lava fountains built a cinder and spatter cone 836 feet high (255 meters) that was named Pu`u `Ō`ō. The frequent short eruptions produced thick chunky lava flows that usually cooled and halted before reaching the coast. However, in July 1983, the lava made its inexorable advance into the nearby Royal Gardens subdivision and destroyed 16 homes. The expensive subdivision was largely abandoned.

In 1986, lava flows cut through the town of Kalapana as the lava made its way to the sea. As the lava field spread, cooled and spread again over the next three years it destroyed many homes and the Visitor Center in Hawai`i Volcanoes National Park. In March 1990, Kilauea entered its most destructive eruption period in modern history. Over the summer more than 100 homes, a church and a store were buried beneath 50 to 80 feet (15 to 24 meters) of lava. [Explosive Images: Hawaii's Kilauea Erupts for 30 Years]

On March 3, 2012, the very last house in the Royal Gardens subdivision was abandoned by 61-year-old Jack Thompson. For years, Thompson had watched as lava claimed the homes of his neighbors, leaving the area to Thompson and a few hardy squatters. The last roads leading to Royal Gardens were closed in 2008, forcing Thompson to hike several miles to reach an access road whenever he needed something from town, but he still refused to leave. Finally on the morning of March 3, Thompson and a friend were evacuated by helicopter as lava finally consumed his home.

Lava in Halema`uma`u crater overflowed the crater's ledge in October 2012 [Video: Lava in Hawaiian Volcano Reaches Highest Recorded Level], and lava reached the ocean in November [Video: Hawaii's Kilauea Volcano Spills Lava into the Sea] when it flooded the ledge of the crater. Lava flowed over the ledge again in January 2013 and continues to flow into the ocean, according to USGS.

The volcano has destroyed hundreds of homes and other structures and frequently damages local utilities and roads. Activity at the summit and along the rift zones can be observed online through webcams placed within the caldera, and information on Kilauea’s activity is updated daily on the USGS website.

Staff writer Becky Oskin contributed to this article.

Additional resources

• Hawaiian Volcano Observatory: Kilauea
• U.S. Geological Survey: 'Hotspots': Mantle Thermal Plumes
• USGS: Volcano Watch

Mount Vesuvius, on the west coast of Italy, is the only active volcano on mainland Europe. It is best known because of the eruption in A.D. 79 that destroyed the cities of Pompeii and Herculaneum, but Vesuvius has erupted more than 50 times. 

Mount Vesuvius facts

Vesuvius in 2013 was 4,203 feet (1,281 meters) tall. After each eruption, the size of the cone changes, according to Encyclopedia Britannica. The volcano also has a semicircular ridge called Mount Somma that rises to 3,714 feet (1,132 m). The valley between the cone and Mount Somma is called Valle del Gigante or Giant's Valley.

Mount Vesuvius is considered to be one of the most dangerous volcanoes in the world because of its proximity to the city of Naples and the surrounding towns on the nearby slopes.

The volcano is classed as a complex stratovolcano because its eruptions typically involve explosive eruptions as well as pyroclastic flows. A pyroclastic flow is a high-density mix of hot lava blocks, pumice, ash and volcanic gas, according to the U.S. Geological Survey. Vesuvius and other Italian volcanoes, such as Campi Flegrei and Stromboli, are part of the Campanian volcanic arc. The Campanian arc sits on a tectonic boundary where the African plate is being subducted beneath the Eurasian plate.

Under Vesuvius, scientists have detected a tear in the African plate. This "slab window" allows heat from the Earth's mantle layer to melt the rock of the African plate building up pressure that causes violent explosive eruptions. In the past, Mount Vesuvius has had a roughly 20-year eruption cycle, but the last serious eruption was in 1944.

Pompeii

Mount Vesuvius destroyed the city of Pompeii, a city south of Rome, in A.D. 79 in about 25 hours, according to History. Because the city was buried so quickly by volcanic ash, the site is a well-preserved snapshot of life in a Roman city. There is also a detailed account of the disaster recorded by Pliny the Younger, who interviewed survivors and recorded events in a letter to his friend Tacitus. [Related: Pompeii 'Wall Posts' Reveal Ancient Social Networks]

Pompeii was established in 600 B.C. and was slowly recovering from a major earthquake that rocked the city in February of A.D. 62. The shallow quake, originating beneath Mount Vesuvius, had caused major damage to the springs and piping that provided the city's water. Reconstruction was being carried out on several temples and public buildings. Seneca, a historian, recorded that the quakes lasted for several days and also heavily damaged the town of Herculaneum and did minor damage to the city of Naples before subsiding. The major quake was followed by several minor shakes throughout the following years. [Image Gallery: Pompeii's Toilets]

Because seismic activity was so common in the area, citizens paid little attention in early August of 79 when several quakes shook the earth beneath Herculaneum and Pompeii. People were unprepared for the explosion that took place shortly after noon on the 24th of August. Around 2,000 residents survived the first blast.

Pliny the Elder, a Roman author, described the massive debris cloud. "It resembled a (Mediterranean) pine more than any other tree. Like a very high tree the cloud went high and expanded in different branches … sometimes white, sometimes dark and stained by the sustained sand and ashes." In Pompeii, ash blocked the sun by 1 p.m. and the people tried to clear heavy ash from rooftops as it fell at a rate of about 6 inches (15 centimeters) an hour. [Image Gallery: Preserved Pompeii — Photos Reveal City in Ash]

Shortly after midnight, a wall of volcanic mud engulfed the town of Herculaneum, obliterating the town as its citizens fled toward Pompeii. About 6:30 a.m. on the following morning, a glowing cloud of volcanic gases and debris rolled down Vesuvius' slopes and enveloped the city of Pompeii. Most victims died instantly as the superheated air burned their lungs and contracted their muscles, leaving the bodies in a semi-curled position to be quickly buried in ash and thus preserved in detail for hundreds of years.

Far away in Misenum, approximately 13 miles (21 kilometers) from Pompeii, Pliny the Younger, the 18-year-old nephew of Pliny the Elder, and his mother joined other refugees escaping the earthquakes rocking their city. They observed, "the sea retreating as if pushed by the earthquakes." This was probably caused by a tsunami at the climax of the eruption, which gives us the time frame for historical record. Pliny writes of "black and horrible clouds, broken by sinuous shapes of flaming wind." He describes people wheezing and gasping because of that wind; the same wind that doomed the people of Pompeii. 

It is believed that around 30,000 people died from the eruption of Vesuvius in 79.

WWII eruption

On March 17, 1944, a two-week-long eruption began with lava from the summit of Mount Vesuvius. In an article by Life Magazine, Giuseppe Imbo, director of the Mt. Vesuvius Observatory, is quoted as saying, "A marvelous thing, my Vesuvius. It covers land with precious ash that makes the earth fertile and grapes grow, and wine. That's why, after every eruption, people rebuild their homes on the slopes of the volcano. That is why they call the slopes of Vesuvius the compania felix — the happy land."

During the eruption, soldiers and airmen of the 340th Bomber Group were stationed at the Pompeii Airfield just a few miles from the base of the volcano. Diaries record the awesome sights and sounds they witnessed in this latest major eruption. Guards wore leather jackets and "steel pot" helmets to protect themselves from rains of hot ash and small rocks. Tents collapsed or caught fire when hot cinders were blown over them.

Sgt. Robert F. McRae wrote in his diary on March 20, 1944, according to the American Geosciences Institute, "As I sit in my tent … I can hear at four- to 10-second intervals the loud rumbling of the volcano on the third day of its present eruption. The noise is like that of bowling balls slapping into the pins on a giant bowling alley. To look above the mountain tonight, one would think that the world was on fire. The thickly clouded sky glows like that above a huge forest fire. Glowing brighter as new spouts of flame and lava are spewn from the crater. As the clouds pass from across the top of the mountain, the flame and lava can be seen shooting high into the sky to spill over the sides and run in red streams down the slopes. ... Today it is estimated that a path of molten lava 1 mile long, half a mile wide, and 8 feet deep is rolling down the mountain. Towns on the slopes are preparing to evacuate. Our location is, apparently, safe. At any rate no one here, civilian or Army authorities, seems too much worried. Lava has not started to flow down this side of the mountain as yet but is flowing on the other side toward Naples."

On March 22, they were forced to evacuate, leaving behind 88 Allied aircraft. After the volcano subsided, they returned on the 30th to find the planes were a total loss. Engines were clogged by ash, control panels were useless tangles of fused wire, canopies had holes from flying rock or were etched to opacity by wind driven ash.

One airman of the 489th Bomber Squadron complained in his diary when Axis Sally broadcast a radio show dedicated to the "survivors" of the Vesuvius eruption (actually the most severe human casualty was a wrist sprained during the evacuation). She told all of Europe that "Colonel Vesuvius" had destroyed all of them. The diarist was justifiably proud of the work he did with his fellows in recovery. By April 15, the planes had been replaced and the 340th Bomber Group was back to full strength and ready to fly missions from their new base. 

Though no soldiers were killed, 26 Italian civilians died and nearly 12,000 were displaced by the 1944 eruption, according to the American Geosciences Institute.

Current status

Since 1944, there have been hundreds of minor earthquakes in the region around Mount Vesuvius. The most serious earthquake rocked Naples in October 1999. The magnitude-3.6 quake was felt as far as 15 miles (24 km) from the base of the volcano and was of the same magnitude as a quake that occurred 17 years prior to the last truly major explosion that devastated Naples in 1631.

In 2016, excavations on the outskirts of Pompeii revealed more victims of the volcanic eruption. Archaeologists discovered the remains of four people, including one teenage girl, in the ruins of a shop, according to a statement from the Soprintendenza Pompei, the Italian authority in charge of managing the ancient site.

Additional reporting by Alina Bradford, Live Science contributor

Additional resources

• BBC: Pompeii: Portents of Disaster
• Italy Magazine: Hiking Mount Vesuvius
• Smithsonian Magazine: Ancient Scrolls Blackened by Vesuvius Are Readable at Last

The United Kingdom has a new tallest mountain, though the formation stands 10,200 miles (16,400 kilometers) south of London.

Mount Hope, part of the British Antarctic Territory (BAT), has been revealed to stand 10,654 feet (3,247 meters) above sea level — 1,236 feet (377 m) higher than the mountain's last measurement. That makes Mount Hope 180 feet (55 m) taller than Mount Jackson, the United Kingdom's previous tallest mountain, which is also located in the BAT.

Did Mount Hope stretch during an earthquake? Did it ride that huge magma bulge in the Antarctic crust higher into the atmosphere? Nope. It just wasn't measured properly the first time around.

For many mountains, official heights are still measured from the ground. That's a complicated process involving trigonometry and relying on several different measurements lining up, with lots of room for human error to creep in.

Researchers are slowly but surely updating all the world's mountain measurements based on much more precise data from orbiting satellites, and that's what led to Mount Hope's new tallest title, according to a statement from the British Antarctic Survey (BAS). [Photos: The World's Tallest Mountains]

Of course, U.K. folks may not feel like Mount Hope is their tallest mountain. Secluded as this landform is on the nearly uninhabited Antarctic continent, most citizens of the United Kingdom are unlikely to see Mount Hope in their lifetimes.

The title of tallest mountain in the British Isles — where U.K. residents generally live — belongs to Ben Nevis in Scotland, a mountain which itself "gained" some height in a remeasurement in March 2016. Ben Nevis' measurement on official maps increased from exactly 1,344 m (4,409 feet) to just under 1,344.5 m (4,411 feet).

None of these mountains are particularly tall by U.S. standards. Mount Rainier, located a few hours' drive from Seattle, is 14,410 feet (4,392 m) tall, almost half again as tall as Mount Hope. North America's tallest mountain, Denali, located in south-central Alaska, is nearly twice as tall as Mount Hope, at 20,310 feet (6,191 m).

The more-precise measurement of Mount Hope is critical for the safety of researchers who fly through the BAT, the BAS said in the statement.

Originally published on Live Science.

Part of the Andes mountain range, Aconcagua is the second highest of the Seven Summits (the highest peaks on each continent), behind only Mount Everest in Asia. At 22,837 feet (6,961 meters), not only is it the highest mountain in South America, it is the tallest peak in all of the Americas, as well as the Southern and Western Hemispheres.

Aconcagua is located in Argentina, in the province of Mendoza, and lies 70 miles (112 kilometers) northwest of the provincial capital, Mendoza, and 9.3 miles (15 km) from the border with Chile.

To the north and east is Valle de las Vacas, and to the west and south is the Valle de los Horcones Inferior. The mountain is part of the Aconcagua Provincial Park, a protected natural area in the Andes that was established in 1983.

Name origins

It is not exactly known where the name Aconcagua came from. One possible origin is that it derived from the native Quechuan words akun, or "summit," ka, or "other" and agua, or "admired" or "feared," according to the Encyclopedia of World Geography. Another possibility is that it comes from Aconca-Hue, an Arauca phrase that translates as "comes from the other side" — meaning the other side of the Aconcagua River. 

The name also may be derived from ackon cahuak, Quechuan words meaning "stone sentinel." Other options for the origin of the name are the Quechuan phrase ancho cahuac or "white sentinel," or aymara janq'u q'awa, meaning "white ravine."

Former volcano

The Andes Mountains were formed as the result of subduction of the oceanic Nazca Plate under the South American continent, according to Marieke Dechesne, a geologist with the U.S. Geological Survey. Aconcagua used to be a volcano, when the oceanic plate dipped at a higher angle under the continent. 

However, sometime in the Miocene, about 8 to 10 million years ago, the subduction angle started to decrease causing the magma to stop melting and increasing the horizontal stresses between the oceanic plate and the continent, causing the thrust faults that lifted Aconcagua up off its volcanic root.

Related: What is plate tectonics?

Life on Aconcagua

The vegetation and wildlife on Aconcagua is concentrated below 13,123 feet (4,000 m), according to the Encyclopedia of World Geography. There are a number of low bushes, such as yellow firewood, yareta and goat horn, and there are open pastures made up of grasses such as huecú and ichu.

Many varieties of birds inhabit the area, including the condor, the purple eagle and a species of snipe called agachona. Spotted sandpipers and torrrentes, a type of duck, thrive in some of the areas with water. Mountain rats and the red fox are among the most common land animals.

Climate at Aconcagua

The mountain is dotted with glaciers, with the largest one being the Ventisquero Horcones Inferior, which is 6.2 miles (10 km) long and near the Confluencia camp on the south face at about 11,811 feet (3,600 m). Other large glacier systems include Ventisquero de las Vacas Sur, Glaciar Este/Ventisquero Relinchos and the north-eastern or Polish Glacier, which is a popular ascent route.

During the summer, the temperature at night above 16,400 feet (5,000 m) is about minus 4 F (minus 20 C), and the typical temperature at the summit is minus 22 F (minus 30 C). The cold, snowy and unpredictable conditions discourage most from trying to summit in winter. Climbers sometimes compare the mountain's difficulty level to that of the "eight-thousanders": 14 Himalayan and Karakoram mountains more than 8,000 meters (26,247 feet) above sea level.

Climbing Aconcagua

Climbers of Aconcagua often struggle with low humidity, low oxygen and fierce winds. Storms are often triggered by humid currents of warm sea air coming from the Pacific Anticyclone, a high-pressure system in the southern Pacific Ocean. These south-bound winds clash against the Andes Mountains, cooling and creating snow on the high peaks, according to Aconcagua Treks. In the summer, the mountain also has its share of lightning storms, creating an even greater risk for climbers. 

When a storm is present at higher elevations, an enormous "mushroom" cloud can often be seen hovering around the summit. Even when the weather is good at base camps, including Plaza de Mulas Base Camp, the mushroom cloud serves as a warning sign that a fierce storm is occurring higher up and that nobody should attempt to climb to those levels, according to Aconcagua Treks. On the contrary, winds blowing from the south are an indication that good weather is coming.

About 60 percent of climbers who attempt the mountain succeed in summiting. Because it is not a highly technical climb, many mistakenly believe that it will be an easy ascent. More than 135 climbers have died on Aconcagua — primarily because of complications of altitude sickness, but also from falls, heart attacks, hypothermia and other causes due to severe weather — and about three climbers die each year on Aconcagua.

The most common route up Aconcagua is the Normal Route along the Northwest Ridge. In total it takes about 21 days from Mendoza, including hiking to the base of the mountain, establishing camps, doing acclimatization climbs, summiting and descending.

Milestones in Aconcagua history

1883: German mountaineer and explorer Paul Güssfeldt makes the first attempt by a European to reach the summit of Aconcagua. Güssfeldt allegedly bribes some local men to be his porters by telling them there is treasure on the mountain, according to Aconcagua Treks. The team has poor equipment and is forced to head back down only about 1,640 feet (500 m) from the summit due to extremely dangerous winds.

1897: American-born mountaineer Edward FitzGerald leads the first known ascent of Aconcagua. Swiss climber Mathias Zurbriggen reaches the summit alone on Jan. 14, followed a few days later by Nicholas Lanti and Stuart Vines, who were also members of the expedition team.

1940: French climber Adrienne Bance is the first woman to summit as part of an expedition from of the Andinist Club of Mendoza.

1953: Argentines E. Huerta, H. Vasalla and F. Godoy make the first winter ascent from Sept. 11 to 15.

1984: Titoune Meunier is the first woman to climb the South Face. She reaches the summit, along with her former husband John Bouchard, using the French 1954/Messner route.

1985: A well-preserved skeleton is discovered at 17,060 feet (5,200 m) on the southwest ridge of Cerro Pyramidal, an Aconcagua sub-peak, providing evidence that the pre-Colombian Incas had climbed Aconcagua.

2007: Scott Lewis, at 87, is the oldest person to summit when he makes his ascent on Nov. 26.

2013: Tyler Armstrong, a 9-year-old boy from Yorba Linda, Calif., is the youngest to reach the summit.

Additional reporting by Traci Pedersen, Live Science contributor.

The eruption of Krakatoa, or Krakatau, in August 1883 was one of the most deadly volcanic eruptions of modern history. It is estimated that more than 36,000 people died. Many died as a result of thermal injury from the blasts and many more were victims of the tsunamis that followed the collapse of the volcano into the caldera below sea level. The eruption also affected the climate and caused temperatures to drop all over the world.

The island of Krakatau is in the Sunda Strait between Java and Sumatra. It is part of the Indonesian Island Arc. Volcanic activity is due to subduction of the Indo-Australian tectonic plate as it moves northward toward mainland Asia. The island is about 3 miles wide and 5.5 miles long (9 by 5 kilometers). Before the historic eruption, it had three linked volcanic peaks: Perboewatan, the northernmost and most active; Danan in the middle; and the largest, Rakata, forming the southern end of the island. Krakatau and the two nearby islands, Lang and Verlatan, are remnants of a previous large eruption that left an undersea caldera between them.

In May 1883, the captain of the Elizabeth, a German warship, reported seeing clouds of ash above Krakatau. He estimated them to be more than 6 miles (9.6 km) high. For the next two months, commercial vessels and chartered sightseeing boats frequented the strait and reported thundering noises and incandescent clouds. People on nearby islands held festivals celebrating the natural fireworks that lit the night sky. Celebration would come to a tragic halt on Aug. 27.

At 12:53 p.m. on Sunday the 26th, the initial blast of the eruption sent a cloud of gas and debris an estimated 15 miles (24 km) into the air above Perboewatan. It is thought that debris from the earlier eruptive activity must have plugged the neck of the cone, allowing pressure to build in the magma chamber. On the morning of the 27th, four tremendous explosions, heard as far away as Perth, Australia, some 2,800 miles (4,500 km) distant, plunged both Perboewatan and Danan into the caldera below the sea.

The initial explosion ruptured the magma chamber and allowed seawater to contact the hot lava. The result is known as a phreatomagmatic event. The water flash-boiled, creating a cushion of superheated steam that carried the pyroclastic flows up to 25 miles (40 km) at speeds in excess of 62 mph (100 kph). The eruption has been assigned a rating of 6 on the Volcanic Explosion Index and is estimated to have had the explosive force of 200 megatons of TNT. (For purposes of comparison, the bomb that devastated Hiroshima had a force of 20 kilotons, nearly ten thousand times less explosive as the Krakatoa eruption. The Krakatoa eruption was about ten times more explosive than the Mount St. Helens explosion of 1980 with a VEI of 5.)

Tephra (volcanic rock fragments) and hot volcanic gases overcame many of the victims in western Java and Sumatra, but thousands more were killed by the devastating tsunami. The wall of water, nearly 120 feet tall, was created by the volcano's collapse into the sea. It completely overwhelmed small nearby islands. Inhabitants of the coastal towns on Java and Sumatra fled toward higher ground, fighting their neighbors for toeholds on the cliffs. One hundred sixty five coastal villages were destroyed. The steamship Berouw was carried nearly a mile inland on Sumatra; all 28 crewmembers were killed. Another ship, the Loudon, had been anchored nearby. The ship's captain Lindemann succeeded in turning its bow to face the wave, and the ship was able to ride over the crest. Looking back, the crew and passengers saw that nothing was left of the pretty town where they had been anchored.

The explosions hurled an estimated 11 cubic miles (45 cubic km) of debris into the atmosphere, darkening skies up to 275 miles (442 km) from the volcano. In the immediate vicinity, the dawn did not return for three days. Ash fell as far away as 3,775 miles (6,076 km) landing on ships to the northwest. Barographs around the globe documented that the shock waves in the atmosphere circled the planet at least seven times. Within 13 days, a layer of sulfur dioxide and other gases began to filter the amount of sunlight able to reach Earth. The atmospheric effects made for spectacular sunsets all over Europe and the United States. Average global temperatures were as much as 1.2 degrees cooler for the next five years.

Mount Tambora & the year without a summer

Tambora is the only eruption in modern history to rate a VEI of 7. Global temperatures were an average of five degrees cooler because of this eruption; even in the United States, 1816 was known as the "year without a summer." Crops failed worldwide, and in Europe and the United States an unexpected outcome was the invention of the bicycle as horses became too expensive to feed.

The Child of Krakatoa

In 1927, some Javanese fishermen were startled as a column of steam and debris began spewing from the collapsed caldera. Krakatoa had awakened after 44 years of calm. Within weeks, the rim of a new cone appeared above sea level. Within a year, it grew into a small island, which was named Anak Krakatoa, or Child of Krakatoa. Anak Krakatoa has continued to erupt periodically, although mildly and with little danger to the surrounding islands. The last eruption was on March 31, 2014. It registered a VEI of 1.

Additional reporting by Rachel Ross, Live Science Contributor

Additional resources

• The Watchers: New eruptive phase begins at Anak Krakatau, Indonesia
• Oregon State University: Volcano World — Krakatau
• Smithsonian Institution Global Volcano Program: Krakatau

Apache Pass

Throughout history, natural features such as mountain ranges, broad rivers and even desert lands have not only been barriers to human movement but have been contributing factors to human cultural conflicts. A perfect example of a natural environment contributing to deadly conflict between two human cultures can be found in the Sky Islands of southeastern Arizona, in a place known in history as Apache Pass.

Sky Islands

Sky Islands are mountain ranges that have become isolated from each other by vast, sediment-filled valleys of grasslands or deserts that act as natural barriers, just like seawater, to the movement of plant and animal species. In the American Southwest and in northern Mexico, 27 Sky Islands are scatted over some 70,000 square miles (181,300 square kilometers) at the meeting point of two great mountain ranges: the Rocky Mountains of the north and the Sierra Madre Mountains of the south. Known as the Madrean Sky Island archipelago, this area has seen over eons of geological time the sinking of the valley floors, resulting in sky island mountain peaks rising to more than 10,000 feet (3,050 meters) in elevation above the dry Chihuahua and Sonoran Desert floors.

Where the mountains meet

Two of these Sky Islands, the Dos Cabezas Mountains and the Chiricahua Mountains, come together in the dry desert of southeastern Arizona and separate the San Simon Valley on the east from the Sulphur Spring Valley on the west. Where the two mountain ranges meet, a 3-mile-long (5 km) mountain valley once allowed the native Chiricahua Apache people, 16th-century Spanish Conquistadors and the 1840s American miners, settlers and soldiers to quickly move between the two desert valleys and avoid many days of traveling around the hot and dry desert lands surrounding the two Sky Islands.

Pass of Chance

Spanish Conquistadors called this valuable mountain valley "Puerto del Dado," meaning the "Pass of Chance." Conflict was common between the local Chiricahua Apache people and the Spanish soldiers who always took a dangerous chance each time they passed through this valley. The saddle of Apache Pass is at an elevation of 4,550 feet (1,387 m) with surrounding mountain peaks rising to a height of 5,250 feet (1,600 m). This elevation is at the upper elevational limit for a desert environment and the pass is populated with plant species common in desert, grassland and woodland habitats.

Freshwater source

But quick passage between two vast desert valleys was not the only reason that Apache Pass was so valuable to all the people living and traveling through this land. Just a few hundred yards west of the mountain's saddle, a natural spring of water (shown here) flowed year round. Apache Spring is the result of a fault zone, initiated more than 1 billion years ago and active throughout geological time. Extensive fractured and faulted rocks are dominant throughout this mountain valley and have long provided a channel for groundwater to constantly flow to the surface at Apache Springs over the millennia. In this vast desert region, a constant source of fresh water is priceless!

Go West

In the 1840s, when young men from around the world heard the call of Horace Greeley to "Go West, young man, Go West," a southern land route to the gold fields of California was needed. The only logical route passed through the American Southwest, but even in winter, the vast deserts were a challenge. Soon, gold miners and settlers alike began moving through Apache Pass for both its convenience and its constant source of fresh water. In 1857, the historic Butterfield Overland Mail Stage Line built a station, shown here, just half a mile west of the Apache Pass mountain saddle, as it began carrying both mail and passengers between St. Louis, Missouri, and San Francisco, California.

Human conflict

Two significant events would soon occur between the Chiricahua Apache people and the U. S. Army. The first occurred in January 1861, when the great Chiricahua chief, Cochise, was wrongly accused of raiding a local ranch. It would become known as the Bascom Affair and resulted in fighting between Chiricahua Apache warriors and the U.S. Army that would last for more than 20 years. The second, the Battle of Apache Pass, occurred in July 1862, when troops from the Union's California Column were attacked by warriors as they moved through Apache Pass toward the New Mexico Territory to battle Confederate soldiers during the American Civil War.

Fort Bowie camp

The California Column established a makeshift Fort Bowie camp in 1862. But with the growing movement of people and goods through this mountain valley, and the now all too common conflict with the local Chiricahua Apache people, the United States governments responded by building a more permanent outpost at the saddle of Apache Pass in 1864. The new outpost was named Fort Bowie in honor of Colonel George Washington Bowie, commander of the 5th Regiment California Column Volunteer Infantry.

Apache Wars

Fort Bowie became the center of military operations for the U.S. Army against the Chiricahua Apaches until the tragic Apache Wars ended in 1886. During that time, U.S. soldiers fought Apache warriors led by both hereditary chief Cochise and a Chiricahua shaman known as Geronimo. When the Apache Wars ended, Fort Bowie was a post with more than 50 adobe and stone buildings. A then-modern heliograph station was also present. Family picnics, a game of tennis and a concert by the post band were all a part of daily post life. By 1894, the need for Fort Bowie had come to an end, and the U.S. Army closed the post and abandoned the buildings.

Journey back in time

Today the old adobe walls of the second Fort Bowie site lie in ruin on the mountain's saddle. These remaining ruins are encased in protective limestone casings. Stabilization of the ruins began in 1964 by the National Park Service, and Fort Bowie National Historic Site was officially established in 1972. The park is some 1.56 square miles (4 square kilometers) in size, and offers visitors a unique glimpse into a time when an emerging country driven by its belief in "manifest destiny" encountered a courageous indigenous people fighting for their very existence.

Take a hike

Visitors to Fort Bowie today must put forth some physical effort. A 1.5-mile (2.4 km) hiking trail leads from the parking lot along Apache Pass Road through a biogeographic transition zone between the Sonoran and Chihuahuan Deserts and the Rocky and Sierra Madre mountains. The trail is rated "moderate" with just under a 200-foot (60 m) elevation gain between the parking area and the fort's ruins. An alternative ADA access to the visitor center is available.

Among the ruins

Walking the trail to Fort Bowie is a journey through the history of the American West. Visitors will pass by the ruins of the Butterfield Overland Mail Stage Station, the first Fort Bowie site, the site of the Bascom's Camp, the still-flowing trickle of water coming from Apache Springs and the post's cemetery. When the post closed in 1894, some 112 graves were believed to be present. Today, between 23 and 33 bodies remain interred in the earth of Apache Pass, including Little Robe, the son of Geronimo who died on Sept. 10, 1885, of dysentery at the age of two, while a prisoner at Fort Bowie.

Historic buildings

When arriving at the saddle of Apache Pass today, visitors will find a barren landscape with the foundations of the 74 historic buildings that once stood here and nearly a dozen adobe and stone wall ruins. Because the National Park Service has purposely engaged in very little development at the site, the integrity of the historic setting still remains. The walk, along with the remoteness and still-open vistas, allow visitors to sense the history that once occurred here. Walking through the ruins of the Cavalry Barracks, shown here, still gives a sense of the challenging military assignment once found at Fort Bowie.

Visiting Fort Bowie

The howling winds that still ripple the flag above the abandoned parade grounds of Fort Bowie help visitors sense the remoteness of this place along Apache Pass. The hot summers and cold winters and the transitional flora and fauna from two vast deserts all made living and working here a challenge for people of all cultures. Visiting Fort Bowie is still as much an emotional experience as an intellectual endeavor.

Plan your trip

A modern visitor center staffed with park rangers welcome all who complete the hike to Fort Bowie. Fort Bowie is open to visitors every day except Christmas and New Years, from 8:00 a,m. - 4:30 p.m. local time. There are no fees to visit this historic site. Visitors should be sure to wear good hiking shoes and a hat, and bring along water to drink. There are no food services nor gasoline available at Fort Bowie.

Teton Mountain Range

The Teton Mountain Range is one of the most dazzling, awe-inspiring natural places still found on the North American continent. The magnificent mountains are located in the state of Wyoming and encompass most of the Jackson Hole valley. The range is a part of the Greater Yellowstone Ecosystem, which is the largest nearly intact natural area in the contiguous United States. Today, many species of animals such as bison, elk, bear, eagles and moose can still be found and enjoyed in the two national parks, seven national forests and two national wildlife preserves that make up the ecosystem.

From above

The Teton Range is a young mountain range that was uplifted only about 9 million years ago. The tallest peak, the Grand Teton, rises some 13,775 feet (4,200 meters). The origin of the naming of the Tetons is shrouded in controversy. Some historians think that French explorers named the mountain range "Les Trois Tetons" (which translates to "the three breasts") to honor the female anatomy. Other historians contend that the mountains received their name from the local Teton Sioux tribe, one of the seven indigenous groups of Lakota people found on the Great Plains of North America.

Long and tall

The Teton Range extends some 40 miles (64 km) in length while rising some 7,000 feet (2,130 m) above the Jackson Hole valley. The area has many lakes including the 15-mile-long (24 km) Jackson Lake, as seen here in this NASA Landsat photo. The primary downstream segment of the Snake River also meanders across the Jackson Hole valley.

From sea to mountains

The geological history of the Teton Range began some 2.7 billion years ago along the edge of an ancient seaway known as the Cordilleran trough. The constant ebbing and flowing seafloor was being filled daily with thick layers of mud, sand and volcanic sediment that would over the years reach miles in depth. Some 60 million years ago, the Farallon Plate under the Pacific Ocean began to subduct below the North American Plate, resulting in the creation of today's Rocky Mountains. Then, 10 million years ago, massive earthquakes triggered by the shifting of the Teton fault began tilting the mountain blocks upward, resulting today in an offset along the valley floor of nearly 30,000 feet (9,140 m).

Young and old

Even though the Teton Range contains some of the oldest rock found in North America, the Tetons themselves are one of the youngest (9 million years old) of North American mountain ranges. The 2.7-billion-year-old metamorphic rock, known as gneiss, make up the vast majority of the Teton Range. Before the collision of the two tectonic plates, these rocks of the Tetons were buried some 18 miles (30 km) below the Earth's surface.

Erosion over time

The striking appearance of the Teton Range is due to both their relatively young age and the ever-present and constant forces of erosion. Massive Pleistocene Ice Age glaciers are responsible for sculpturing the rugged high peaks with their deep U-shaped canyons. These Pleistocene glaciers disappeared some 10,000 years ago, but smaller glaciers reformed in the Teton Range during the Little Ice Age (1400 CE - 1850 CE). Today, there are 11 active glaciers within the Teton mountains, 10 of which are large enough to be named on U.S. Geological Survey maps. The Teton Glacier is shown here just to the right of the Grand Teton peak.

Slice and dice

The movement of glaciers through the Teton Range resulted in the carving of many deep depressions in the valley floor. Six, jewel-like morainal lakes are now found at the base of the Teton Range. Jackson Lake, shown here, is the largest of the glacier lakes covering 40 square miles (104 square kilometers) with a maximum depth of 438 feet (134 m). More than 100 additional backcountry and alpine lakes and ponds are also found scattered throughout the Teton Range.

Opportunities to wade

The many opportunities to enjoy water throughout the Teton Range include world-class fishing along the Snake River, which meanders along the base of the mountains. With its headwaters on the Two Ocean Plateau inside of Yellowstone National Park, the Snake River is a major river of the Pacific Northwest region of North America. The Snake River, shown here flowing near the Grand Teton, is 1,078 miles (1,735 km) long and is the largest tributary of the Columbia River.

Splendor in all directions

With such natural beauty everywhere, it is little wonder that the Grand Teton National Park was established in February 1929. The park encompasses some 484 square miles (1,250 square kilometers). Park elevation ranges from 6,320 feet, (1,926 m) to 13,775 feet (4,200 m). Archeological evidence suggests that early hunter-gatherer Paleo-Indians first entered this land some 11,000 years ago. The Shoshoni tribe claimed this region when French and American fur trappers entered the beautiful river valley early in the 19th century in search of beaver pelts. A herd of American bison is shown here grazing in one of the meadows in front of Mt. Moran.

Perfect for plants

The floor of the Jackson Hole valley, as well as the many mountain valleys, are predominately composed of a loose rocky soil that is ideal for water to percolate through it. With such ideal conditions of moisture and soil, more than 1,000 species of vascular plants grow within the park's boundaries. Big leaf sagebrush, Artemisia tridentata , dominate the valley floor, intermingled with a vast diversity of wildflowers. Conifers dominate the mountain sides and canyon regions. A patch of lupine flowers, Lupinus perennis, is shown here and is one of many species of wildflowers that add seasonal beauty to the national park.

Home to many

With such a lush and diverse natural environment, wildlife abounds throughout the Teton Range. Sixty-one species of mammals, including bears, moose, badgers and more, are found in the area's alpine, forest, sagebrush flat and wetland zones. The national park is renowned for its excellent trout fishing. More than 341 species of birds, including the yellow-headed blackbird (Xanthocephalus xanthocephalus) have been documented within the park's boundaries. Both golden eagles, Aquila chrysaetos, and bald eagles, Haliaeetus leucocephalus, are commonly seen soaring above the vast meadows along the Snake River in search of a delicious rabbit, carrion or trout dinner.

Say 'Cheese'

Grand Teton National Park is a photographer's paradise. Beautiful landscape scenes are found around every twist and turn. For those willing to take a 3/4-mile (1.2 km) hike, one of the most iconic photos within the park is of the Old Patriarch Tree which rises above the sagebrush flats with the Cathedral Group Peaks as a background. The Old Patriarch Tree is a limber pine (Pinus flexilis) and thought to be some 1,100 years old. Limber pines are famous for their twisting and turning growth patterns as they stand against the strong winds and storms that sweep across the mountain range.

Untouched beauty

The Teton Range and the surrounding national park continues to be one of the best places in North America to experience the beauty and diversity of undisturbed natural flora and fauna. In the summer of 2017, this special place will be the site of yet another of nature's spectacular events, when the center line of a total solar eclipse will pass over Grand Teton National Park on the morning of August 21, reaching totality at 11:35 a.m. local time. It will certainly be an ideal time to visit and enjoy the many natural wonders still found in this small corner of our natural world.

Denali, once called Mount McKinley, is the tallest mountain in North America. Located in south-central Alaska, the mountain's peak is 20,310 feet (6,190 meters) above sea level, also making it the third highest of the Seven Summits — the highest mountains on each of the seven continents — following Mount Everest in Nepal and Aconcagua in Argentina. By one measure, it could be considered the third tallest mountain in the world.

Denali's height was recalculated at 20,310 feet in September 2015, based on GPS survey data; And that number was an update to a 2013 estimate of 20,237 feet (6,168 m), which was calculated using a remote-sensing technique called interferometric synthetic aperture radar (InSAR). Both numbers placed Denali's summit lower than the original calculation of 20,320 feet (6,194 m) established in 1953 by Bradford Washburn, a mountaineer, photographer and cartographer.

Naming controversy

The native Koyukon Athabascan people call the mountain Denali, which is usually translated as "The Great One." However, linguist James Kari of the Alaska Native Language Center at the University of Alaska Fairbanks, wrote in the book "Shem Pete’s Alaska" that the name is based on a verb theme meaning "high" or "tall."

A gold prospector, William Dickey, named it Mount McKinley in 1896, after President William McKinley. Dickey was among a large group of prospectors who were part of the Cook Inlet gold rush. When asked why he chose to name the mountain after then-presidential nominee McKinley, he cited McKinley's support of the gold standard. McKinley, who was from Ohio, never visited his namesake mountain or any part of Alaska.

The park in which the mountain resides was established as Mount McKinley National Park on Feb. 26, 1917. The state of Alaska officially changed the name to Denali in 1975 and asked the federal government to do so too. However, when the park was tripled in size and renamed Denali National Park and Preserve in 1980, the federal government retained the name Mount McKinley, according to the Alaska Dispatch News.

A number of efforts had tried to switch the name to Denali. Hudson Stuck, who made the first ascent of the mountain in 1913, wrote a book titled "The Ascent of Denali." In the preface of the book, he called for "the restoration to the greatest mountain in North America of its immemorial native name." Past attempts were blocked by lawmakers from Ohio.

In August 2015, with President Barack Obama's approval, the U.S. Department of the Interior officially renamed the mountain Denali. According to the Department of Interior, a 1947 federal law gave Secretary Sally Jewell the authority to change geographic names through the U.S. Board on Geographic Names.

Where is Denali?

Denali is about 170 miles (275 km) southwest of Fairbanks and about 130 miles (210 km) north-northwest of Anchorage. It is part of the Alaska Range and the centerpiece of Denali National Park, which covers six million acres (24,281 square km) of land.

While it has long been believed that the Alaska Range, which spans much of south-central Alaska, was formed by tectonic activity, it has remained a mystery until recently because it is more than 300 miles (500 kilometers) from Alaska's southern coast, the closest source of mountain-building activity. A 3D computer model project shed some light on how the low angles and unusual bent in a geological fault further inland combined to form the mountain range.

How tall is Denali?

There is a distinction between measuring "highest" and "tallest." The highest mountain is determined by measuring a mountain's highest point above sea level. The tallest mountain is measured from base to summit. Using that measurement, Denali is taller than Mount Everest. Denali rises about 18,000 feet (5,500 meters) from its base, which is a greater vertical rise than Everest's 12,000-foot rise (3,700 meters) from its base at 17,000 feet (5,200 meters).

In his book, "The Finest Peaks: Prominence and Other Mountain Measures" (Trafford, 2005), Adam Helman wrote, "The base to peak rise of Mount McKinley is the largest of any mountain that lies entirely above sea level." Based on its topographic prominence, or the distance between its summit and lowest contour line, Denali is the third most prominent peak after Mount Everest and Aconcagua in South America.

But Denali and Everest are both dwarfed by Mauna Kea in Hawaii. When measured from the ocean floor to its summit, that mountain is 33,476 feet (10,204 meters) tall. However, only 13,803 feet (4,207 meters) rise above sea level.

When Denali was remeasured in 2015, some believed that the mountain was shrinking due to the fact that it was quite a bit shorter than when measured in 1953. Actually, the mountain is growing by about .04 inches (1 millimeter) per year, according to NASA. This tiny but significant growth is due to the continuous impact of the Pacific and North American plates.

Denali's climate

The upper half of Denali is permanently covered with snow and many glaciers, some more than 30 miles (48 km) long. The mountain's extreme cold, which can be minus 75 degrees Fahrenheit (minus 60 degrees Celsius) with wind chill down to minus 118 F (minus 83 C), can freeze a human in an instant. An automated weather station at 18,700 feet (5,700 meters) records temperatures.

More than 400,000 people visit Denali National Park and Preserve each year, primarily between May and September. At the beginning of the 2017 climbing season, around 800 mountain climbers registered with Denali National Park to ascend the mountain. More than 32,000 people have attempted to reach the summit, but only a few reach the top. There was about a 60 percent success rate in 2016.

There are many guides who lead climbing trips to Denali, and it is classified as an extremely challenging expedition due to the severe weather and difficulty in acclimating. Because of its far northern latitude of 63 degrees, Denali has lower barometric pressure than the world's other high mountains.

Key dates in Denali's history

In 2017, Denali National Park turned 100 years old. Here are some more facts about the mountain:

1794: British explorer George Vancouver refers to Denali in his journal.

1902: A mapping expedition led by geologist Alfred Brooks explores the area.

1903: Judge James Wickersham and four team members make it as far as the 10,000-foot (3,048-meter) mark, which is now known as Wickersham Wall.

1906: Physician and explorer Frederick Cook claimed to have reached the summit, but this assertion was discredited, as was his claim to have reached the North Pole in 1908.

1913: Hudson Stuck, Walter Harper, Harry Karstens and Robert Tatum are the first to reach the south summit.

1932: Bush pilot Joe Crosson lands the Cosmic Ray Party at 5,700 feet (1,524 meters) on the Muldrow Glacier. This expedition sees the first two known fatalities on the mountain. More than 100 climbers have perished on the mountain since.

1947: Barbara Washburn becomes the first woman to summit the mountain.

1960: The first topographic map of the mountain is published by Bradford Washburn. The first party to camp on the mountain is a Meiji University team.

1967: The first successful winter ascent is accomplished by Art Davidson, Dave Johnston and Ray Genet.

1970: The first solo ascent (Naomi Uemura); first all-female ascent; and the mountain's first ski descent are recorded.

1982: The first woman to complete a solo climb is Dr. Miri Ercolani.

1988: Vernon Tejas is the first solo climber to ascend the mountain in the winter and survive.

1993: Joan Phelps is the first blind climber to reach the ascent.

1995: Merrick Johnston, 12, is the youngest female to summit.

2001: Galen Johnston, 11, becomes the youngest male to reach the summit, Toshiko Uchida, 70, becomes oldest woman to summit.

2013: Alaska resident Tom Choate, 78, breaks the record as the oldest male to reach the summit.

2015: The mountain's name is officially changed to Denali.

Additional reporting by Alina Bradford, Live Science Contributor.

Additional resources

• National Park Service: Denali National Park and Preserve
• U.S. Department of the Interior press release on name change
• Nasa: Same Mountain, Different Measurements

Mount Etna is the largest active volcano in Europe and one of the world's most frequently erupting volcanoes. It is also the volcano with the longest record of continuous eruption. Mount Etna also made an appearance in a "Star Wars" movie.

Mount Etna often comes to life in short, violent bursts called paroxysms. Its outbursts produce enough lava each year to fill Chicago's Willis Tower (the former Sears Tower), a 2012 study found. It erupted on February 27, 2017, but soon quelled. Small eruptions occurred in 2016 and 2015, and in 2014, it burst into a spectacular nighttime display. The last major eruption was in 1992.

Located near the east coast of the island of Sicily, Mount Etna is 10,900 feet (3,329 meters) tall with a base circumference of about 93 miles (150 kilometers). Mount Etna is a series of nested stratovolcanoes with four distinct summit craters. There are two central craters, called Bocca Nuova and Voragine; the Northeast crater; and the newest Southeast crater, which was formed by an eruption in 1978. Strombolian eruptions, which produce ash, tephra and lava fountains, are fairly common in these craters. The eruptions of early 2013 were mostly strombolian eruptions. The January 2013 eruption was from Bocca Nuova, and the February eruptions are most noticeable from the Southeast crater.

The mountain's largest feature is the Valle del Bove (Valley of the Ox), a large horseshoe-shaped caldera on the eastern slope. There are numerous fissures and vents on the flanks of the volcano that often produce slow-moving pyroclastic flows at low altitudes. These flows threaten agriculture, public utilities and transportation in the heavily populated towns surrounding the mountain.

History of eruptions

Mount Etna has a longer written record of eruptions than any other volcano. The first recorded observation of a Mount Etna eruption was written by Diodorus Siculus in 425 B.C. The mountain was also described by the Roman poet Virgil in the Aenid. Roman records from 122 B.C. indicate a large eruption blocked the sun for several days and caused widespread damage to the town of Catania on the coast. Roman taxes were cancelled for 10 years to help locals rebuild. Catania was in the path of destruction again in A.D. 40, 1169 and 1185.

Then, in 1669, in one of the mountains most destructive eruptions, 1,500 people were killed when the town of Nicoli was destroyed by an earthquake originating beneath Mount Etna. In Catania, the townspeople made one of the first known attempts at damage control by digging a trench to divert the lava slowly advancing upon the town. Unfortunately, the diverted lava then threatened the nearby town of Paterno, causing a brief battle that halted the attempt. Lava overtopped the Catania city wall and obliterated half the town again.

Mount Etna has almost continuous eruptive activity near the summit craters and in the Valle del Bove, but these vertical eruptions pose little threat to inhabitants.  Flank eruptions cause more damage as vents and fissures can open at much lower, inhabited elevations. In 1928, the village of Mascali was obliterated in only two days when a fissure opened up near the foot of the mountain. In 1960, agricultural land was destroyed by ejected lava and ash fall.

In 1992, the town of Zafferana was endangered by lava flow and was saved by a more successful attempt at volcano control. Earthen dams were erected to try to contain the lava in the Valle del Bove but were shortly overtopped by the flowing lava. U.S. Marines were then called upon to help with “Operation Volcano Buster” by flying cargo helicopters to drop huge concrete blocks at the edge of the lava tunnel. Additional blocks, suspended underneath the helicopters were used like croquet mallets to knock the grounded blocks into the mouth of the tunnel. These efforts slowed the progression of the lava for the two weeks necessary to dig a diversionary channel for the lava, which was stopped just about half a mile (850m) from the city limit. Unfortunately several homes, fields, orchards and vineyards around the town were completely buried. [Countdown: History's Most Destructive Volcanoes]

Sitting on a fault

There are many theories as to why Mount Etna is so active.  Mount Etna, like other Mediterranean volcanoes such as Stromboli and Vesuvius, rests on the subduction boundary where the African tectonic plate is being pushed under the Eurasian plate. Although they appear to be geographically close, Etna is actually quite different from the other volcanoes. It is actually part of a different volcanic arc. Etna, rather than sitting directly on the subduction zone, actually sits just in front of it.

Etna sits on the active fault between the African plate and the Ionian microplate, which are both being subducted together beneath the Eurasian plate. Current evidence suggests that the much lighter Ionian plate may have broken and part of it forced backwards by the much heavier African plate. Magma directly from Earth’s mantle layer is being sucked into the space created by the tilting Ionian slab. This phenomenon would account for the kinds of lava produced by eruptions of Mount Etna, which resemble the type of lava produced along deep sea trenches where mantle magma is forced through Earth’s crust. Lava from the other volcanoes is the type produced by the melting of existing crust rather than the upwelling of the mantle layer. There are other possible explanations for the unusual activity of Etna, such as existence of a hotspot or a window-like crack in the African plate.

In spite of the mystery and the danger, locals call Mount Etna “Mongibello,” the beautiful mountain. They grow olives, grapes and fruit in the soil enriched by the fallen ash. Tourism thrives as visitors come to ski or to marvel at the display of fire fountains during an eruption. One resident of Zafferana expressed the local’s love of their fiery mountain. As he left his home for the last time before it was engulfed by the lava, he set the table with a snow-white cloth and a bottle of his finest wine as a gift for Mongibello.

Stand-in for fiery planet

In the "Star Wars" prequel "Revenge of the Sith," the climax occurs on the planet Mustafar amid fiery explosions and lava flows. According to the website Star Wars Places, cinematographer Ron Fricke visited Mount Etna as it was erupting and filmed lava explosions. Those shots were combined with special effects created on a studio set. The actual lava in the movie was made with a chemical called methocil, which is a food additive.

An Antarctic mountain with a unique, pyramid-like shape is suddenly internet-famous, with countless theorists contemplating its origin. Some are wondering whether an ancient civilization created the rocky, pyramidal structure, and others are pointing toward outer space, speculating about the involvement of aliens.

But Occam's razor — the idea that the simplest explanation is usually the right one — points to a far more mundane cause: Those steep, pyramid-like sides are likely the work of hundreds of millions of years of erosion, experts told Live Science.

"This is just a mountain that looks like a pyramid," Eric Rignot, a professor of Earth system science at the University of California, Irvine, told Live Science in an email. "Pyramid shapes are not impossible — many peaks partially look like pyramids, but they only have one to two faces like that, rarely four." [Photos: The World's Weirdest Geological Formations]

The pyramidal mountain, which doesn't have a formal name, is one of the many peaks that make up Antarctica's Ellsworth Mountains, which were discovered by the American aviator Lincoln Ellsworth during a flight on Nov. 23, 1935, according to a 2007 research paper that was published by the U.S. Geological Survey (USGS).

More specifically, the unnamed mountain — located at 79°58’39.25"S 81°57’32.21"W — is in the southern part of the Ellsworth Mountains in an area called Heritage Range, which is known for its extraordinary fossils, including those of Cambrian-period trilobites from more than 500 million years ago, according to a 1972 USGS report.

The mountain isn't that tall by planetary standards — just 4,150 feet (1,265 meters) — or a little less than one-fifth the height of Denali, the tallest mountain in North America, according to Google Earth. The mountain may not have Denali's height, but its unique pyramidal shape sets it apart, said Mauri Pelto, a professor of environmental science at Nichols College in Dudley, Massachusetts.

Freeze-thaw erosion likely led to its pyramid-like shape, Pelto said. This happens when snow or water fills up cracks within a mountain during the day. When night falls and temperatures drop, the snow freezes and expands, turning into ice. The expanding ice causes the cracks to grow, Pelto said.

This freeze-thaw erosion happens countless times, leading to the creation of larger cracks that can, eventually, cause entire rock sections to break off, he said. These forces likely also shaped other pyramidal mountains, including the Matterhorn in the Alps, he said.

Three of the mountain's four sides appear to have eroded at about the same rate. "It suggests, since it came out so evenly, that the rock type is fairly uniform," Pelto said. "You don't have any rock layers that are harder to erode."

In other words, the nameless mountain is likely "all in one rock layer," Pelto said. "It's not a very big mountain, so it's not that surprising." 

However, the eastern ridge of the mountain is decidedly the black sheep of the family. Instead of descending downward like the other ridges, that fourth side extends east, rising toward even higher terrain, Pelto said.

"The erosion probably wasn't as uniform [on the eastern side]," he said.

Pelto added that although some news outlets are saying that the mountain is newly discovered, that's very unlikely to be the case. There's a research base for climate scientists to the south of the mountain in an area known as the Patriot Hills.

"You can actually probably see this mountain from up there in the Patriot Hills," Pelto said.

As for the conspiracy theorists who are wondering about the mountain's pyramidal shape, "at least they're thinking about something," he said. "In the end, maybe they'll learn something in the process."

Original article on Live Science.

Mountaineers and other adventurers now have a more accurate map of which peaks in the U.S. Arctic are the tallest.

Though Denali is the uncontested highest peak in North America — with a summit elevation of 20,310 feet (6,190 meters) — there has been a more than 50-year debate over which U.S. mountain can be crowned the tallest beyond the Arctic Circle. U.S. Geological Survey topographic maps from the 1950s show either Mount Chamberlin or Mount Isto as the highest mountain in the eastern Alaska Arctic region.

A new mapping technique, known as fodar, has finally settled the debate. At 8,975.1 feet (2,735.6 m), Mount Isto is the tallest peak in the U.S. Arctic, and Mount Chamberlin (at 8,898.6 feet, or 2712.3 m) is only the third highest. [Photos: See the World's Tallest Mountains]

Fodar, which uses airborne photography to survey and map terrain, revealed a third tall peak: Mount Hubley. This mountain surpassed Mount Chamberlin by about 16 feet (5 m) of height, claiming second place in the list of highest U.S. Arctic mountains. 

Glaciologist Matt Nolan, lead-author of the study published today (June 23) in the journal The Cryosphere, had been mapping glacier volume change using the fodar technique, which he invented.

Mapping mountains

"These mountain peaks just happened to be located in the same area as the glaciers we were studying, and several of the peaks ended up in our maps," Nolan, of the University of Alaska Fairbanks, said in a statement. "Because we were interested in understanding the performance limitations of fodar in steep mountain terrain, it seemed a natural fit to combine this validation testing with settling the debate on which peak was the tallest."

Fodar is similar to airborne LiDAR (Light Detection And Ranging), which uses aircraft-mounted lasers to scan a landscape and create 3D maps of the terrain, but is a more affordable mapping option, Nolan said. [The University of Alaska has a more detailed explanation of how fodar works.]

"The core equipment is a modern, professional DSLR camera; a high-quality lens; a survey-grade GPS unit; and some custom electronics to link the camera to the GPS," Nolan explained. And, he added, fodar can be operated by the pilot flying in a small, single-engine plane.

Summiting the Arctic

Nolan worked with champion American skier and ski mountaineer Kit DesLauriers to map the peaks from the air and on the ground. While Nolan flew a Cessna 170B and used his fodar technique, DesLauriers was climbing up and skiing down the mountain range.

DesLauriers, who was the first person to ski down the Seven Summits, tracked her position using the same GPS unit Nolan had in his plane.

"Instead of a normal rest stop to eat and hydrate, I used the rare moments standing still to note my location and time in a field journal so that Matt could have as much data as possible to compare our measurements," DesLauriers said in the statement. "The process made climbing the peaks, which took on average a 10-hour summit push after a multiday approach, more difficult but also more rewarding."

The challenging expedition was necessary, Nolan said, as it offered control points on the ground to compare the airborne measurements to, ensuring accuracy.

Using fodar

Now that fodar has settled the Arctic peaks' debate, Nolan said the mapping technique can be used for measurements beyond mountain heights.

"Though determining peak heights was a fun and useful study, our primary use for fodar is in change detection in the cryosphere [the planet's frozen regions]," Nolan said.  

The same maps created from fodar to measure peak heights can help scientists understand how snow and glacier melt will affect the region, Nolan said. He has used fodar to measure coastal erosion, permafrost melt, landslides and more.

"The possibilities are truly unlimited," he said.

Original article on Live Science.

Introduction

A snow leopard was collared in Kyrgyzstan in the spring of 2016, the second of these elusive creatures to have been collared by conservationists in six months. The female was specifically found in the Sarychat-Ertash Strict Nature Reserve of Eastern Kyrgyzstan. The finding suggests that at least this population of the endangered cats may be rebounding, scientists said. [Read more about the collared snow leopard]

Mama cat

The cat was a female who had lactated, suggesting she had at least one pup. That, combined with the fact that another snow leopard that was collared in the country was photographed with three pups, suggests the big cats feel comfortable breeding and raising young. That could suggest the population is rebounding. [Read more about the collared snow leopard]

Camouflage

Can you spot the snow leopard? The snow leopard has a mottled coat that allows it to blend in perfectly to its rocky, snow-flecked surroundings. [Read more about the collared snow leopard]

Snowy peaks

The snow leopard lives in 12 different countries in Asia, usually in rocky, mountainous areas. They have been prey to poachers seeking their internal organs and furs, as well as shepherds hoping to protect their flock. As a result, their populations plummeted in the 1990s. [Read more about the collared snow leopard]

Camp view

Here, a view from the Sarychat-Ertash Strict Nature Reserve of Eastern Kyrgyzstan, where the snow leopard was collared. [Read more about the collared snow leopard]

Denali — the tallest peak in North America — not only has a new name (or, more accurately, its old name), but a new official height, geologists announced Wednesday (Sept. 2).

The Alaskan mountain had been called Mount McKinley until Sunday (Aug. 30), when Secretary of the Interior Sally Jewell said it would officially be given its former name — Denali, which translates to "the tall one." But "the tall one" is not quite as tall, it seems, as geologists once thought: The newly measured height of 20,310 feet (6,190 m) is 10 feet less than the official altitude of 20,320 feet established in 1953 by Bradford Washburn, a mountaineer, photographer and cartographer. (Not to worry, the peak is still the tallest in North America, followed by Canada's Mount Logan, with an elevation of 19,551 feet, or 5,959 m.)

Washburn calculated the peak's height using aerial photographs and a triangulation method. Mountains can be thought of as simple triangles for measurement purposes. In that sense, a surveyor can calculate the distance between two points on the ground and the angles between the top of the mountain and each of those points. [Photos: The World's Tallest Mountains]

"If you have two angles, you know the third, because the sum of the angles is 180 [degrees]," Peter Molnar, a geologist at the University of Colorado, Boulder told Live Science in May, referring to the measurement of Mount Everest's height.

Advances in technology, primarily the introduction of global positioning systems (GPS), have led to more accurate information on the elevation across Earth's surface.

Other measuring methods have produced different estimates of Denali's height. In 2013, scientists surveyed Denali with a remote-sensing technique called interferometric synthetic aperture radar (InSAR), which relies on radar signals to show elevation changes. The result? The method pegged Denali's summit at 20,237 feet (6,168 m). Though the technique can be effective at providing broad elevations for maps, it doesn't churn out precise spot elevations, particularly in steep terrain, the U.S. Geological Survey (USGS) noted.

"It does some things really well — it penetrates clouds and smoke — but it's not a high-accuracy survey," said Blaine Horner, of the survey company CompassData. "It's more of a medium-sized brush."

In fact, geologists in the field didn't think the new 20,237-foot height estimate — an 83-foot drop from the 1950s number — was precise because it hadn't been peer reviewed and there were inherent errors involved in the measurement.

"Radar will not ever be as accurate as boots on the ground," Horner told Live Science.

To get a more precise number, a team of climbers, led by Horner, installed two GPS receiver antennas at the mountain's summit and one lower down on the mountain. Signals from satellites gave precise locations for these antennas to make results from triangulation more precise. Easy, right?

Nope. Installing those antennas meant the scientists and climbers had to make a steep trek all the way to Denali's summit. Besides the physical challenges, the team also had to work night shifts. [How to Measure a Mountain's Height]

Even though Denali is one of the coldest places on Earth, on the lower parts of the mountain, weather can be relatively warm. That can make for risky climbing when the only thing between you and a fatal fall through a crevasse, or deep crack in the glacier, is a layer of sometimes-frozen snow.

"When that snow is frozen, you walk right across [the crevasse], but once it gets really hot, that snow bridge may not support you anymore," Horner told Live Science. To beat the heat when beginning their ascent of Kahiltna Glacier, the researchers scheduled their activities seemingly backward in time, waking up at 9 or 10 p.m. and beginning their hike at 1 a.m. so that they would get to camp by "night" at 7 a.m., he said.

They started their trek in mid-June, when the sun is in the sky about 24 hours a day in that region, so they didn't need flashlights for the nighttime hiking.

The final height estimate accounted for various factors, including the depth of the snowpack and the average sea level.

The majestic mountain has more accurate digits, something that is both practical — particularly for earth scientists and even mountaineers, pilots and geographers — and important information for the public, Suzette Kimball, USGS acting director, said in a statement.

"It is inspiring to think we can measure this magnificent peak with such accuracy," Kimball said. "This is a feeling everyone can share, whether you happen to be an armchair explorer or an experienced mountain climber."

Follow Jeanna Bryner on Twitter and Google+. Follow us @livescience, Facebook & Google+. Original article on LiveScience.

Each spring, amidst stories of successful firsts, come tales of overcrowding, fighting and tragedy on Mt. Everest, including last week’s avalanche that killed at least 13 Sherpas who were setting ropes on the mountain’s most popular climbing route.

Nevertheless, hundreds of people from dozens of countries are at Base Camp right now, and many are planning to make a bid for the summit of the world’s tallest peak in the next few weeks, though those bids may be complicated by news that Sherpas have decided to vacate the mountain for the season. Why does Everest continue to be so alluring, despite the costs, the crowds and the risks?

The answer likely differs for each climber, and studies suggest that people who take risks tend to perceive them differently from people who avoid the same behaviors. But for adventurers who are drawn to Everest, the mountain’s top is a lifelong dream that inspires intense preparation and a deep sense of reverence.

Makings of the Deadly Everest Ice Avalanche

“I can wax poetically for hours about this, but I thoroughly love the mountain,” said Alan Arnette, a mountaineer and respected Everest blogger based in Fort Collins, Colo. “It represents the ultimate, the pinnacle for many people.

“I think Everest is a magical mountain with magnetic qualities,” he added. “It’s like a light to bugs that attracts people once they hear about it.”

The modern urge to climb Everest began more than 150 years ago when British surveyors determined that the 8,848-meter peak was the tallest in the world. Everest soon became a “third Pole” as explorers raced to become the first to stand on top of it.

PHOTOS: The World's 'Eight-Thousander' Mountains

“From the moment it was identified as the highest mountain, it became an object of fascination,” said Maurice Isserman, a historian at Hamilton College in Clinton, New York, and author of "Fallen Giants: A History of Himalayan Mountaineering from the Age of Empire to the Age of Extremes."

“There are more interesting mountains to climb. There are more beautiful mountains. There are more challenging mountains that are a better experience. But it’s a trophy. It’s the biggest.”

When asked by The New York Times why he wanted to climb Everest, British mountaineer George Mallory, who died on the mountain during his third expedition there in 1924, famously answered, “Because it’s there.”

Not everybody wants to climb Everest, though, and those who do likely have a strong internal drive to seek out thrills that may be at least partially programmed by genetics, said Andreas Wilke, a psychologist at Clarkson University in Potsdam, N.Y. Decision-making studies show that some people are more likely to pursue or avoid risk than others.

But the spectrum of risk-taking behavior is broad and more complex than psychologists once thought. In his studies of people who engage in extreme recreational activities like bungee jumping and SCUBA diving, Wilke has met skydiving wallflowers and chain-smokers who buy extensive car insurance. People who pursue risks in some parts of their lives, in other words, don’t necessarily live on the edge in every way.

Instead, when Wilke has asked people to evaluate their behaviors, he finds that they often don’t consider what they do to be as risky as it might seem to others, either because they have a skill set that gives them confidence or because in their minds, the benefits outweigh any fear involved. That balance of risks and rewards differs from person to person.

Daredevils Secretly Climb Shanghai Tower

“I would not climb Everest. I have other things to do, but in plain English, I’m also too scared to do it,” Wilke said. “But I would do things some mountain climbers would not do, like lecture to 500 undergraduates.”

From an evolutionary perspective, Wilke said, risk-taking behavior can be advantageous, particularly in men, because it signals strength and fitness to members of the opposite sex. In line with that theory, a successful Everest climb can convey status and prestige.

“If you said you went to Everest, you by definition climbed the highest mountain available to mankind,” he said. “That’s a very clear, non-fakable hierarchy. We can be very competitive in nature.”

Have Sherpas Had It?

For many people who have topped Everest, though, it’s about much more than hubris. Surpassing the “death zone” above 8,000 meters, standing on top of the world and returning home safely is an experience unlike any other.

“It brings into focus what’s important to you,” said Arnette, who summited Everest on his fourth attempt in 2011. “There are a thousand reasons to turn around and only one to keep going. You really have to focus on the one reason that’s most important and unique to you.

“It forces you to look deep inside yourself and figure out if you really have the physical, as well as mental, toughness to push when you want to stop,” he added. “When you come home, you realize you are able to face a wall and overcome that wall.”

This story was provided by Discovery News.

The Andes are the world's second greatest mountain region and new research suggests that at least one portion of that region has been lying about its age.

For years, the evidence has been piling up that the Central Andes surged into being about 10 million years ago -- a very short time ago geologically speaking. Now new evidence from volcanic materials on the Puna Plateau suggests that the area was already 4 kilometers high as far back as 36 million years ago. If so, it sets the area apart from the Altiplano, to the north, which is lower and younger, and adds yet another twist to the puzzling processes that created the range.

Photos: World's Largest Salt Flat

Team of researchers ventured to the very remote Puna Plateau in Argentina and collected volcanic ash samples that they could study in the lab to determine not only how long ago the ash was erupted from volcanoes, but how far above sea level.

The age was determined by studying the ratios of uranium and lead in tiny zircons crystals. These two elements serve as an internal radiometric timekeepers for volcanic rocks, since uranium decays into lead at well-known rates over millions of years.

Next, the researchers looked for the elevation clues in bits of volcanic glass, or obsidian, that formed in the ash.

“The little glass shards cool and take on water from the environment,” explained Robin Canavan, a PhD candidate at Yale University and the lead author on a paper about the work in the March 31 issue of the journal Geology.

Photos: The World's 'Eight-Thousander' Mountains

It's the water that reveals the elevation, because as moist air moves up mountains and the water rains (or snows) out, the air tends to lose the heavier kinds of water first -- those made from heavy hydrogen and heavy oxygen isotopes. The effect can be seen today in surface waters in mountains around the world: lighter isotopes of hydrogen and oxygen in H2O are more enriched at higher elevations. Those same isotopes of oxygen and hydrogen can be found captured in volcanic glass.

By putting the radiometic dating together with the paleo-elevation information from the volcanic glass, the team could determine what height the Puna Plateau was when the volcanic ash was deposited on the ground.

“Our work suggests that the region south of the Central Andean plateau, the southern half the Puna, has had a surface elevation very close to modern 4 kilometers (13,000 feet) for 36 million years,” Canavan said. “This pushes it pretty far back from what previous work suggested.”

The discovery is especially appreciated by geologists studying the nearby Altiplano, which appears to have a very different history.

“The Puna and other Altiplano look similar, but they have different mechanisms,” said Carmala Garzione, professor and chair of the Department of Earth and Environmental Sciences at the University of Rochester. “There are fundamentally different processes that are leading to the uplift.”

Photos: Stunning Auroras Seen Over Swedish Mountains

Both are part of the uplift caused by the subduction of ocean crust under the South American continent. But there are other things going on to thicken the crust and cause the mountains to buoy especially high in the Andes compared to other subduction zones.

The Altiplano, for instance, has a large, high basin. Whereas the Puna has several smaller basins. This, to Garzione, suggests that the Puna has been shortened, or squeezed, which could play a role in its earlier high elevation.

“The next step will be to get more geophysical data to get more information at depth,” said Garzione. Seismic data could help show the structures inside and under the mountains to explain the history even better. There is historic seismic data from the 1990s that is being reprocessed by other researchers to learn more about the subsurface, she said.

This story was provided by Discovery News.

Maps lie. Or, at least, they contain a whole lot of guesswork.

The view of Earth's ocean bottoms, for example, on Google Earth or some other global map gives you the impression we have the seafloors completely charted. But there are huge guesses regarding what's under the waves for the about 90 percent of the world's oceans that have not been directly mapped by ships using sonar.

That's why an improvement on an unusual method to see under the waves from space is such a big deal. The new method was presented at the Ocean Science Meeting last week in Honolulu.

PHOTOS: Changing Face of Earth in 2013

“When you go into Google Earth and look at sea floors, you see two things,” said ocean gravity mapper David Sandwell of the Scripps Institution of Oceanography at the University of California at San Diego. “One is the predicted depth and structure from gravity measurements. Two is that every once in a while you'll see a clear strip with more detail.”

Those rare strips are where a research ship has actually motored over and measured the seafloor bathymetry.

Where ships haven't mapped the seafloor, the job has been left to satellites, particularly those that can measure heights of the seas. Those satellites essentially “feel” the gravitational effects of undersea mountains. New satellite sea surface altimetry datasets are enabling scientists to see smaller and smaller mountains that rise from the sea floor (known as seamounts), but remain hidden by the oceans.

NEWS: Gravity Satellite Felt Japan Quake from Space

“The ocean surface will have a bunch of waves and other temporal changes,” said Seung-Sep Kim of Chungnam National University in South Korea. “The seamounts create a (permanent and very subtle) bump. They can only be seen by satellite.”

This bump can be translated into a gravity measurement of a seamount, which gives an indication of its size.

Kim and his colleagues reported on Feb. 28 that they have successfully tested new sea surface altimetry data from the Earth-observing satellites CryoSat-2, Envisat and Jason-1 on a known seamount to see how well it worked. The triple dataset is a huge improvement on the older altimetry data that for some time consisted of a single satellite. Now it can be used to reduce the guesswork in the bathymetry maps with which the general public is familiar.

“CryoSat is the most important,” said Sandwell. “It's designed to measure ice volume changes, but it's also a really super ocean altimeter.”

ANALYSIS: Twitter: GOCE Burned Up Over Falkland Islands

The ocean altimeters are also much better at seamount detection than satellites like GRACE (a twin satellie mission that has been taking data since 2002) and GOCE (which finished its gravity-mapping mission and reentered in 2013) that directly measure dips and bumps in Earth's gravity -- another indication of mountains and other significant features on the seabed.

The reason, said Sandwell, is that GRACE is 400 kilometers (250 miles) above the surface of the Earth. Because the force of gravity tapers off quickly with altitude, the resolution of the gravity map GRACE generates is only as precise as its distance from the Earth. GOCE orbited 200 kilometers (124 miles) up, which means a factor of 2 better resolution than GRACE, but that's still an altitude at which most seamounts will remain undetected.

The sea surface, on the other hand, is only a few kilometers above the sea floor, so its resolution is on the scale of a few kilometers -- which means unknown seamounts will have a hard time hiding.

This story was provided by Discovery News.

In mist-enshrouded cloud forests, the ecosystem can differ dramatically from those nearby. But exactly why hasn't been clear.

Now, some of the secrets of these foggy mountaintop stretches are being revealed. One surprise: On cloudy days, these misty forests may actually see more light than they would on a perfectly sunny day.

"Sometimes it's brighter than complete sunlight," Keith Reinhardt, a plant physiologist at Idaho State University, said last month at the annual meeting of the American Geophysical Union in San Francisco. That's because some of the filtered light scatters off the cloudsand is combined with direct sunlight before reaching the leaves.

The leaves must also deal with a wider range of light and water conditions than other mountain forests, the research found. [In Photos: Life Up in the Clouds]

Ethereal places

Anyone who has been on a mountain hike has seen how the misty mountaintop ecosystem can be a world away from one just a few hours' hike below.

To find out why, Reinhardt and his colleagues placed light, temperature and moisture sensors on spruce fir trees in the southern Appalachian forestsstretching from Virginia to the Great Smokey Mountains. The mountains, about 6,500 feet (2,000 meters) high, are cool and wet, with cloud bottoms often grazing the forest floor, and mountaintops shrouded in fog for 60 to 80 percent of all the days in the growing season, Reinhardt said.

Unsurprisingly, on the few sunny days, the trees were exposed to bright light, and completely cloudy days were very, very dark.

But on partly cloudy days, the leaves see a huge range in light conditions, from very dark to blindingly bright. That's because light scattered from cloud edges combines with the direct sunlight, amplifying the light exposure. While an individual leaf may see less light, the forest on average, as an ecosystem, sees quite a bit, Reinhardt said.

Afternoon energy boost

In other forests, the process of making food from light, known as photosynthesis, tends to drop off in the afternoon. But these sky island trees see a boost in their energy harvesting into midday, perhaps to take advantage of a period when a diffuse light penetrates the formerly dark corners of the forest, the researchers said.

The team also measured how easily air bubbles form in the xylem, the water-transporting vascular system of trees. The more easily such "embolisms" form, the more sensitive trees are to drought.

Despite being enshrouded in mist all the time, the trees, which grow at higher, and potentially dryer, elevations, didn't form embolisms easily and so tended to be more drought-resistant than similar trees in other ecosystems. 

"These trees might not be designed for when the clouds are there, but when the clouds are not there," Reinhardt said. "These are relatively high elevation sites, so when the clouds are not there, it can get pretty dry."

Follow Tia Ghose on Twitter  and Google+. Follow us @livescience, Facebook & Google+. Original article on LiveScience.

A big chill 2 million years ago bred glaciers that scoured mountains across the planet, pouring trillions of tons of muck into the oceans, researchers said today (Dec. 18) in a study published in the journal Nature.

"We really see the ability of climate to quite dramatically change erosion rates on the surface of the planet," said Frédéric Herman, a geologist at the University of Lausanne in Switzerland.

Geologists have long suspected that a cold climate boosts erosion rates, thanks to clues in ocean floor sediments. When Earth entered a global freeze-thaw cycle starting 6 million years ago, huge pulses of sand and mud started appearing in sediment cores drilled from seafloor — a possible sign that glaciers were suddenly grinding down continents. Researchers are also intrigued by the link between glaciations and a burst in erosion because atmospheric carbon dioxide rises and falls with the waxing and waning of the ice ages, especially starting about 2.7 million years ago.

One way to quickly trap carbon dioxide (on the geologic time scale) and remove it from the atmosphere is in buried sediments. Thus, glaciers, erosion and climate could all combine in one big feedback loop — glaciers advance, increasing erosion, which removes carbon dioxide and further cools the Earth, Herman said.

But the link between big freezes and increased erosion has been hotly contested, because some scientists questioned whether seafloor sediments can accurately gauge erosion that took place millions of years ago. [The Power of Ice: Glacier Erosion]

"Sediments are a proxy for erosion, and the problem is there are a lot of assumptions about what happens when you erode sediments and deposit them," Herman said. "The record you use is usually not complete."

Rocks reveal the past

So Herman and his colleagues turned to the actual rocks. The team assembled a global erosion database from nearly 18,000 cooling ages measured at mountains, plains and valleys. The cooling age technique, which is similar to measuring a rock's age from isotopes (atoms of different weights), tracks how quickly erosion exposed a rock buried below Earth's surface. Rocks cool as they rise to the surface from warmer depths.   

The big picture reveals global erosion rates for the past 8 million years, focusing on mountainous regions. Slowly eroding continental edges and plains do not rise quickly enough to reveal potential cooling ages in such a short time period, Herman said.

The findings confirm that erosion picked up starting about 6 million years ago, when Earth's climate started cooling down, and doubled about 2 million years ago, the researchers report.

The most striking speedup in erosion was at midlatitude ranges such as the Alaska Range, New Zealand's Southern Alps and the Chilean Andes, where glaciers are most likely to vanish when Earth warms between glacial cycles, the researchers found. "That variability might be causing these large changes," as mountains switch between erosion dominated by rivers of water or ice, Herman told LiveScience's OurAmazingPlanet. (Water and ice sand down rocks at different speeds.)

Which came first?

As for linking erosion with carbon dioxide, the cooling ages can't prove which came first, the uptick in glacial gouging or the downturn in atmospheric greenhouse gases.

"This really highlights the large magnitude of the increase at midlatitudes," Herman said. However, "we don't know which one was first."

Even though some areas can't be resolved, the new study convincingly demonstrates the global scale of recent erosion, David Egholm, a geophysicist at Aarhus University in Denmark, said in a commentary on the study also published today in Nature. "Their results suggest that climate drives erosion, because, unlike tectonic activity, climate can change synchronously on a global scale," Egholm, who wasn't involved in the study, said.

Email Becky Oskin or follow her @beckyoskin. Follow us OurAmazingPlanet @OAPlanet, Facebook and Google+. Original article at LiveScience's OurAmazingPlanet.

Of all of the Seven Summits, Carstensz Pyramid ranks highest in the number of alternative names. The 16,024-foot (4,884-meter) mountain is also called Puncak Jaya, Puncak Jaya Kesuma, and Jaya Kesuma. Indonesians typically vary between the names Carstensz Pyramid and Puncak Jaya.

Besides its multiple names, the mountain has also had a bit of controversy regarding its continent designation, but that is primarily a political rather than geographical dispute. The Dutch ceded control of the area in 1962 to Indonesia, and the area remains politically unstable. Carstensz Pyramid is within the borders of Indonesia, which is on the Asian continent. The mountain is located in the western half of the island of New Guinea, in the Indonesian province of Papua. Most experts consider the island to be part of the Oceania continent, which also includes Polynesia, Melanesia, Micronesia, New Zealand and Australia.

Climbers who do the Seven Summits climb Mount Everest as the Asian summit. Some expand the Seven Summits to eight, also climbing Australia’s Mount Kosciusko, which is just 7,310 feet (2,228 meters).

While Carstensz Pyramid is indisputably the highest island peak and the highest point between the Himalayas and the Andes, its official height has come into question. The officially recognized height of the Carstensz Pyramid is 16,024 feet (4,884 meters); some sources, including Australian navigational air maps, peg its height at 16,503 feet (5,030 meters).

How did Carstensz Pyramid get its name?

Carstensz Pyramid is named for John Carstensz, a Dutch seaman and explorer who, along with his crew, were the first Europeans to see the mountain. When he returned to Holland in 1623, people didn't believe his description of a snowy mountain near the equator.

Where is Carstensz Pyramid?

It is in the western central highlands of Papua and part of the mountain range known as the Sudirman Range or the Dugunduguoo, about 55 miles (86 kilometers) from the island's southern shore. The mountain, which is composed of middle Miocene limestone, was formed by a collision between the Australian and Pacific plates. [Related: What is Plate Tectonics?]

Carstensz Pyramid is close to the world's largest goldmine in Grasberg, making it a highly protected area.

Climate of Carstensz Pyramid

Glaciers and snow, even on such a high mountain, is an odd sight near the equator. While there are no glaciers on Carstensz Pyramid’s peak, there are several on its slopes, including the Carstensz Glacier, the Meren Glacier and Northwall Firn.

Daytime temperatures can vary from 53 F (12 C) to 98 F (37 C) and can go as low as 18 F (-8 C) at night.Because of its proximity to the equator, there is little variation in the mean temperature during the year, and there is not much seasonal fluctuation in the glaciers. Satellite images show that most of the glaciers are retreating rapidly and some have disappeared altogether the last 20 years.

Climbing Oceania’s highest summit

The mountain has seven faces, and climbers can take a number of routes to summit Carstensz Pyramid. Harrer or Normal Route is the usual route up the mountain. Its ascent and descent usually takes 12 to 15 hours, so climbers have to start out early.  The other two routes are the East Ridge, a long scrambling route, and the American Direct, which is a long steep climb directly up the North Face.

It is best climbed from April to November. Reaching the base of the mountain is a major challenge in itself, as climbers have to make their way through the tropical jungle of West Papua. Due to its remoteness, combined with government red tape, nearly constant tribal wars and political instability in the region, it is one of the less frequented Seven Summits.

Notable dates in Carstensz Pyramid history

1936: The Royal Netherlands Geographical Society sponsored a group of climbers led by amateur mountaineer Antonie Hendrikus Colijnto climb the highest peak. They ended up climbing nearby Ngga Pulu, which was considered the highest at the time.

1962: Austrian climber Heinrich Harrer and his team, which included Russell Kippax and Albert Huizenga, were the first to summit. He came back the following year to climb Ngga Pulu but was stopped. He became a friend of the Dalai Lama, and their relationship is depicted in the movie “Seven Years in Tibet.”

1995 – 2005: Carstensz Pyramid was closed to climbers as the government stopped granting permits to climb the mountain.

With an elevation of 16,066 feet (4,897 meters), Mount Vinson is the highest mountain in Antarctica. It is located on the southern part of the main ridge of the Sentinel Range of the Ellsworth Mountains.

Also called Vinson Massif, Mount Vinson is more than 750 miles (1,200 kilometers) from the South Pole, making it the most remote of the Seven Summits. It was also the last discovered, last climbed and last named of the Seven Summits.

Antarctica's highest peak has a prominence of 16,066 feet (4,897 meters), making it the eighth most prominent mountain in the world.

Where is Mount Vinson?

Situated near the Ronne Ice Shelf south of the Antarctic Peninsula, Mount Vinson is in the Ellsworth Mountains, which comprises two sub-ranges — the Sentinel Range in the north and the Heritage Range in the south. This is not only the home of Antarctica's highest point, but also the next five highest summits on the continent.

Naming Mount Vinson

Mount Vinson is named for U.S. Rep. Carl Vinson of Georgia, who served in Congress from 1935 to 1961 and was the former chairman of the House Armed Services Committee. He was a champion of government funding for American exploration of Antarctica.

For many years, there was no specific name given to the highest peak and it was part of a group of mountains was known as Vinson Massif. The name encompassed the area's numerous summits, as "massif" is defined as a dense group of connected mountains forming a distinct section of a range.

As a result of several climbing and GPS mapping expeditions to the Sentinel Range, it was suggested in 2006 to the Antarctic Place Names Committee of the U.S. Geological Survey that the name Mount Vinson be used to signify the highest summit of the Vinson Massif. This suggestion was accepted, and the name of the highest peak was officially changed.

Climbing Mount Vinson

Temperatures in the Ellsworth Mountains average around minus 20 degrees F (minus 30 C), making it the coldest of the Seven Summits. The best period for climbing is December through February during Antarctic summer, when temperatures rise to minus 29 F (minus 20 C) and the sun is out 24 hours a day.

Most climbers ascend up the Branscomb Glacier, known as the Normal Route, and make it in about 10 days. About 1,000 climbers have summited Mt. Vinson, much fewer than the other Seven Summits. While other summits are more challenging from a technical climbing perspective, the cold, windy conditions and the short window of opportunity to climb keep many climbers from making it to the top. There is also the cost involved, which can be $30,000 or more because of the summit's remoteness.

Milestones in Mount Vinson's history

1935: U.S. aviator Lincoln Ellsworth spies a small part of the northern end of the Ellsworth Mountains from the air.

1957: A U.S. Navy reconnaissance flight led to the discovery of Mount Vinson in December 1957. Several ground aerial surveys performed between 1958 and 1961 originally put Mount Vinson at 16,864 feet high (5,140 meters).

1961: U.S. scientists Tom Bastien and John Splettstoesser climb Mount Wyatt Earp on the far northern end of the Sentinel Range.

1966-1967: The American Antarctic Mountaineering Expedition is the first to summit.  The team was led by Nicholas Clinch and included Barry Corbet, John Evans, Eiichi Fukushima, Charles Hollister, William Long, Brian Marts, Pete Schoening, Samuel Silverstein and Richard Wahlstrom. Corbet, Evans, Long and Schoening reached the summit on Dec. 18, 1966. The rest of the team made the summit over the following few days.

1979: Following the route the Americans had established a decade earlier, Werner Buggisch and Peter von Gizycki from West Germany and Victor Samsonov from the Soviet Union were the second group to summit on Dec. 22, 1979. Their expedition was not authorized. They left Samsonov's ski pole with a red flag, which helped the USGS get a better handle on Vinson's height, which was then determined to be 16,066 feet (4,897 meters). It was originally surveyed at 16,864 feet high (5,140 meters) in 1959.

1983: Dick Bass and Frank Wells — two U.S. billionaire businessmen — developed the Seven Summits concept (the highest peaks on each of the seven continents). The were joined by British climber Sir Chris Bonington and some Japanese climbers, as well as Rick Ridgeway and Steve Marts, who filmed the event. Bonington reached the summit first, with Bass, Wells and the others reaching the top a week later.

1985: A group led by Canadian climber Pat Morrow summited Vinson on Nov. 19. In the following years, Morrow's Adventure Network International (ANI) led Vinson climbers and other Antarctic adventurers.

1988: Lisa Densmore, a U.S. climber, was the first woman to summit. Vern Tejas of the United States made the first solo ascent.

1991: German climber Rudi Lang was the first to ascend solo using a direct route on the west face.

1992: Robert Anderson, a U.S. climber, made the first ascent via the south face.

1997: American climber Conrad Anker was the first to summit using the west ridge.

2000: U.S. climbing team John Armstrong, Conrad Anker, Liesl Clark, Dave Hahn, Jon Krakauer, Andrew McLean, Rob Raker and Dan Stone made the first ascent using the east face.

2006: The headwall route, which had been used since 1966, was changed when ALE established the first ropes up the broad rib at the northern end of the west face.

Mount Elbrus isn’t technically a mountain — it is an inactive volcano located in the western Caucasus mountain range, near the Georgian border in Kabardino-Balkaria and Karachay–Cherkessia, Russia.

With an elevation of 18,510 feet (5,642 meters), it is part of the Caucasus Range that straddles Asia and Europe, although most geographers place it in Europe. This makes it the tallest mountain in Europe and one of the Seven Summits, the highest mountains in each of the continents and elite climbers aspire to summit all of them.

Mount Elbrus’ prominence —a measure of how distinct a mountainis from nearby peaks — is 15,554 feet (4,741 m), making it the 10th most prominent mountain in the world. The east summit is slightly lower at 18,442 feet (5,621 m).

Meaning of the name

"Mingi-Tau" is the name given Elbrus by the Balkars, the Turkic people of the Caucasus region. This translates to "resembling a thousand mountains," as a homage to the mountain’s size.

Before the Balkars, the mountain was known as Sobilus, which is Latin for "pine cone" This is a variation of strobilos, meaning "a twisted object," which is an apt description of the mountain's summit.

The mountain also has a mythological history. In Greek mythology. Zeus chained Prometheus to the mountain as punishment for stealing fire from Zeus and sharing it with mankind. The name also has Persian origins, a derivation of Harā Bərəzaitī, a mountain in Persian mythology.

Elbrus’ climate

The climate is most conducive to climbing in July and August, when the weather is at its most stable.

Even in the summer, nighttime temperatures average 18 F (minus 8 C). Temperatures above the snowline can fall as low as minus 22 F (minus 30 C) during the day during the winter.

Winter is coldest in the western part. It lasts from October to April above 6,562 feet (2,000 m).

While the mountain is inland, it is positioned between the Caspian Sea and the Black Sea. These two large bodies of water have an impact on wind and precipitation.

Climbing Elbrus

Elbrus has a unique cable car system, which was built on the south side of the mountain from 1959 to 1976. The cable car reaches 12,500 feet (3,658 m).  From there, most climbers take the Standard Route up the south side to the summit.

While the lack of crevasses can lull climbers into a false sense of safety, the Standard Route is challenging due to the snow, high winds and a high elevation. About 15 to 30 climbers die each year, which is a fairly high ratio of climbers to climber deaths when compared to other mountains.

Another unique feature of Elbrus is the system of huts for resting, including the Barrel Huts, which are located at 13,600 feet (3,962 m). There is also a snow-cat to take climbers up to 15,750 feet (48,000 m).

Mount Elbrus has 22 glaciers that feed three rivers — Baksan, Malka and Kuban. The mountain is covered with snow year-round.

While it can be a dangerous climb, it is considered among the easiest of the Seven Summits. The typical climbing season is May to September. The harsh winter conditions keep all but the most experienced climbers off the mountain.

It takes most climbers less than a week to summit, which is short compared to the other Seven Summits.

Another high point in Europe

Mount Elbrus gets the title of highest in Europe. Another, perhaps better known, peak is Mont Blanc. It is the highest mountain in the Alps and the European Union. Its elevation is 15,781 feet (4,810 m) above sea level.

Key points in Elbrus history

1829: Kabardinian Killar Khashirov, a guide for a Russian army scientific expedition, was the first to reach the east summit, which is the lower of the two summits.

1874: The higher west summit was ascended by Akhia Sottaiev, a Balkarian guide, who was working for a group that was led by Brit Florence Crauford Grove and included Englishmen Frederick Gardner and Horace Walker, and Swiss climber Peter Knubel.

1932: The first hut, called "Prijut 11," was built at of 13,650 feet (4,160 m).

1942: During World War II, German forces had occupied all the territories north of the Baksan Valley and were gradually taking the mountain valleys in the Western Caucasus. Eventually a German Alpine division commandeered Priut 11. They retreated by early1943 and by mid-February Elbrus was back under Soviet control.

1956: A group of 400 climbers ascended the mountain to commemorate the 400th anniversary of Kabardino-Balkaria, the regional Soviet Republic.

1991: The outhouse at the Pruitt Hut — before it burned down a few years later — was named the world’s worst outhouse by Outside Magazine. While it gets a lot of use from climbers who drink a lot of water and take altitude medication, it doesn’t smell because it is completely frozen.

1997: Russian adventurer Alexander Abramov led an expedition that drove a modified Land Rover to the summit, making it the highest mountain climbed by a vehicle.

1998: A group of climbers started a fire while cooking and burned down Priut 11.