Imagine opening your eyes for the first time and seeing that the sky is full of green doughnuts.

This was the view that greeted NASA's Nancy Grace Roman Space Telescope, which just activated its powerful, 300-megapixel infrared camera for the first time.

The telescope, which launched to space on Aug. 30, is partway through a months-long commissioning process, with NASA scientists testing and tuning each of the spacecraft's instruments as it undertakes a million-mile (1.6 million kilometers) journey to Lagrange point L2 — an orbital "parking spot" where the competing gravity of Earth and the sun will hold Roman in place, alongside the James Webb Space Telescope (JWST) and other scientific spacecraft.

Roman's camera system, known as the Wide Field Instrument (WFI), hasn't been fully focused yet, so the stars look like lime-colored loops in this debut test image. But so far, all systems are working as they should, according to a NASA statement.

By the time Roman is ready to beam home its first full science images in early 2027, it will be capturing cosmic snapshots as crisp and detailed as those from the Hubble Space Telescope ‪—‬ but each of Roman's images will cover an area 100 times larger than Hubble's.

"After years of effort to build and test the instrument on the ground, we now have confirmation that it is operational in space. This is a huge milestone," Josh Schlieder, chief WFI scientist at NASA's Goddard Space Flight Center in Maryland, said in the statement. "There is much to do, but we are on our way to groundbreaking science."

The wavy rows of squares in the new image are key to Roman's photo-taking power. Each square represents one of Roman's 18 detectors, which translate photons from distant light sources into electrical signals that encode enormous images of the universe. Scientists are preparing for the telescope to beam roughly 1.4 terabytes of data — about five to 10 times the storage capacity of an average smartphone — back to Earth every day.

With all that data, NASA scientists expect Roman to push the frontiers of some of the biggest mysteries in astronomy. Planned long-term surveys of distant galaxies will help scientists discover new objects and calculate the expansion of the universe, potentially shedding new light on the phenomenon of dark energy.

The telescope will also contribute to the search for alien life. By selectively blocking out starlight with Roman's built-in coronagraph — another instrument that NASA successfully tested this week — the telescope will be able to zoom in on exoplanets with unprecedented precision, free from stellar glare. These observations could increase the number of known alien worlds from the current count of over 6,000 to more than 100,000 by the end of Roman's planned 10-year mission.

But in a final piece of good news, that 10-year mission now looks likely to double. According to NASA, a successful thruster burn (combined with bonus fuel loaded onto the spacecraft at launch) means that Roman may be looking at 22 years worth of power rather than 10. Like Hubble, which has continued operating far beyond its initial mission parameters, Roman may be an orbital gift that keeps giving for decades.

Are you a UFO fanatic? Find out with our extraterrestrials quiz!

In movies and TV shows, it's a popular motif: A dead Viking is placed on a boat, and it drifts slowly out to sea; from land, an archer shoots a fiery arrow that falls onto the boat and engulfs it in flames.

It's been seen in the 1958 movie "The Vikings," the History Channel show "Vikings" and fantasy series such as "Game of Thrones." But did the Vikings actually do this?

To find out, we asked experts whether there is any archaeological or historical evidence to support the idea.

Archaeological evidence

Our sources noted that a burial like this would leave little archaeological evidence. Such "practices would leave little trace, and they are unverified by archaeological sources," Howard Williams, an archaeology professor at the University of Chester in the U.K., said in an email.

Erin McGuire, an anthropology professor at the University of Victoria in Canada, also noted this limitation. From "an archaeological standpoint, we have no evidence for this very common motif," McGuire told Live Science in an email, adding that it would be hard to differentiate a fire set by a fire arrow from a regular fire. Additionally, shipwrecks "with human remains are very, very rare globally," McGuire added. "It takes particular kinds of environmental conditions for them to be preserved and I know of none from the Viking Age."

However, the Vikings were master seafarers and frequently cremated their dead. And there is evidence that Vikings burned ships, McGuire noted. We "do have archaeological examples of ships and parts of ships that were burnt during funerary practices while still on land and were buried after being burned," McGuire said. These include the ninth-century Myklebust ship, a burnt Viking ship that was found in a burial mound in Norway and was built for a rich person, possibly a king.

Historical evidence and legends

Perhaps the closest historical evidence for the fire-arrow ritual comes from Ahmad ibn Fadlan, a 10th-century Arab traveler who went to the Volga River in what is now Russia and spent time with Viking groups there. In ibn Fadlan's written account, a Viking chieftain is placed on a boat, which is set ablaze.

However, there are some key differences between this account and the scene depicted in popular culture. First, there's no flaming arrow; rather, the boat was lit on fire by a person described as a chief mourner. Additionally, the boat and its dead chieftain were on land, not on the water.

Although not strictly historical, there are some legendary and mythical accounts of burials at sea that were possibly inspired by real events. "From medieval literature we have rare references to boats/ships involved in funerals over water," Williams said.

In the epic poem "Beowulf," the funeral of the Danish king Scyld Scefing sees the dead king placed on a ship that drifts off to sea. In the 13th-century Scandinavian book "Heimskringla," by Snorri Sturluson of Iceland, the "sea-king Haki [was] set adrift and set alight so that his body burned with those of his slain retinue," Williams said, and in another story by Sturluson, "the god Baldr is set adrift and his ship set alight by his brother Thor."

The funeral of Baldr has been particularly notable, McGuire said, noting that it inspired J.R.R. Tolkien to include a similar scene in his "Lord of the Rings" books.

Practical problems

Experts noted that this kind of fire-arrow burial might not have even been possible.

"Personally, I consider cremation at sea using a ship set alight from the shore with flaming arrows to be rather unrealistic," Matthias Toplak, head of the archaeology department at the Viking Museum Haithabu in Germany, told Live Science in an email. "My own experiments show that it is not at all easy to set something alight with flaming arrows."

He noted that fire must burn at a high temperature for several hours for cremation to be effective. "At sea, the ship would probably sink before the body had been sufficiently cremated," Toplak said. "Apart from that, there is of course also the danger that a ship ablaze and adrift would be driven by currents or the wind into other ships or harbour facilities."

McGuire also noted that there are practical problems with the idea. "if you send a burning boat out onto the water, how do you stop it from drifting ashore with rather grisly contents?"

Overall, the scholars we spoke with doubted that the Vikings used fire arrows to burn funeral boats set adrift at sea. "However romantic the idea of such a funeral scene may be, I unfortunately consider it highly unlikely," Toplak said.

Instead, Williams suspects 20th-century Hollywood movies played a major role in the creation of this idea. "I strongly suspect this specific trope owes its origin to the 1958 film The Vikings and the concluding scene of Einar's funeral," Williams said.

It "says little about how 'Vikings' treated their dead," Williams added, "but tells us a lot about our valorised ideals of fate, honour and death linked to both fantasy and historical 'Vikings.'"

See how much you know about ancient norsemen with our Viking quiz!

If your blond preteen seems to be turning into a brunette, you're not imagining things. For some children, hair that starts out platinum blond gradually becomes darker and may end up dark brown, or even black, as they grow.

So what causes this change?

The short answer is that hair color is controlled by a complex interplay of genes, pigment-producing cells and, later in childhood, hormones. Scientists understand many of the genes involved in hair color, but they are still trying to find out why some blond children's hair darkens while others' locks remain blond for life.

"It depends on their genetic inheritance," Desmond Tobin, a professor of dermatological science at University College Dublin, told Live Science in an email.

Hair gets its color from a pigment called melanin, which is produced by specialized cells called melanocytes in hair follicles. There are two main types of melanin: eumelanin, which produces brown and black shades, and pheomelanin, which contributes yellow and red tones to hair. The amount and type of melanin produced by a follicle largely determine the color of the hair that grows from it.

In general, more eumelanin means darker hair. For example, during pregnancy, high levels of estrogen and progesterone can encourage hair darkening as more eumelanin is produced.

The activity of hair follicles isn't necessarily fixed throughout childhood. As children grow, the biological signals controlling pigment production can change, too.

From blond to brown

For many blond children, the most noticeable darkening happens around puberty, typically between about 10 and 13 years old, Tobin said.

It is likely the hormonal changes during puberty, such as estrogens and androgens that stimulate an increased production of eumelanin, that gradually turn blond hair darker over time, he said. "Those that remain blond typically have a genetically determined reduction in eumelanin pigment formation," Tobin added.

Exactly how hormones might cause this change, however, is still something of a mystery.

One clue comes from a group of hormones called melanocortins. One of these, alpha-melanocyte-stimulating hormone (alpha-MSH), is involved in telling pigment-producing cells to make more melanin. In our skin, alpha-MSH is triggered by ultraviolet (UV) light. UV light can damage DNA in skin cells that, via a cellular signaling pathway, encourages the release of alpha-MSH to make the skin tan.

But in hair, things get, well, hairy. Scientists haven't shown that a rise in alpha-MSH, testosterone, estrogen or any particular hormone is what makes blond hair darken.

The melanocortin system shows that hormones can tell pigment-producing cells to make more eumelanin. What remains unclear is whether changes in this system are actually responsible for blond hair darkening during puberty.

"We haven't yet identified the genes that control this process," Wojciech Branicki, a researcher who studies the genetics of human pigmentation at Jagiellonian University in Poland, told Live Science in an email.

One possibility Branicki suggested is that hormones may affect children's hair follicles differently depending on their genetic background. For now, researchers don't know which genes are involved or how they interact with hormonal changes during puberty, as more research is needed.

Branicki posits that in some children, the hormones could induce the production of melanin or the transport of pigment within the hair follicle. In other words, two children could start out with similarly blond hair but respond differently to the hormonal changes as their bodies develop. One might continue producing relatively little eumelanin and stay blond, while the other's follicles might gradually ramp up pigment production, causing new batches of hair to grow darker.

"Research on human genome variation is quite advanced, but not all aspects have been explained yet," Branicki said.

In the summer of 2008, New York City lowered the threshold for activating its emergency heat plan.

The city had historically relied on the National Weather Service threshold of a heat index of 105 F (40.6 C), but they noticed that people were getting heat stroke at lower temperatures.

As part of a wider effort, they changed the alert threshold: it would trigger if the temperature reached 100 F (37.8 C) for a day, or 95 F (35 C) for two days in a row. When the threshold was reached, city officials conducted targeted outreach, including to vulnerable groups, like homeless people; alerted residents on their phones; launched measures to protect the power and water supply; and opened cooling centers.

Lowering this threshold correlated with a more than 50% reduction in hospitalizations for heat stroke and related illnesses on hot days.

New York's case study offers one of the clearest examples of an intervention that worked to protect people from deadly heat.

As the planet warms, we will need to find more of these solutions. The consensus among scientists is that the most effective way to avoid the worst health outcomes of climate change is to slow warming by reducing carbon emissions. Limiting warming to 1.5 degrees Celsius (2.2 degrees Fahrenheit), for instance, would mean 11,600 fewer deaths due to wildfire smoke exposure in the U.S. annually, compared with warming of 5.4 F (3 C).

But even if we rapidly reduce emissions, climate change will have wide-ranging effects on our health

So what measures actually work to protect people's health? Live Science reviewed dozens of studies and talked with 19 climate and health experts at universities and health and climate associations, to identify the most promising solutions to two of the biggest climate-related threats: extreme heat and wildfire smoke.

Some interventions have demonstrated a reduction in deaths or disease at the population level, while others have used modeling to predict health impacts or rely on proxy measures.

"The strongest evidence is where these approaches reduce illness, hospital visits or death," said Charles Leonard, an associate professor of epidemiology at the University of Pennsylvania, told Live Science, "not just heat exposure, pollution levels or other intermediate markers."

Most solutions do not offer the level of clarity of the New York example, however. Many reduce temperatures or alter human physiology in ways that are likely to decrease the number of heat-related deaths or cases of illness. But a deeper examination reveals limited evidence that many seemingly intuitive interventions, such as cooling centers, are effective on a societal level.

For both heat and wildfire smoke exposure, we analyzed the evidence to see which interventions have actually worked.

Extreme heat

Air conditioning and heat pumps

Evidence grade: Strong

One of the most common interventions for managing indoor temperatures is the use of mechanical systems with refrigerants, such as air conditioning or heat pumps.

Air conditioning has been tied to reduced hospital admissions in California and reduced heat-related deaths at Texas prisons. During a heat wave in Portugal, patients admitted to an AC-supported hospital had a 40% lower risk of dying than those in wards without AC. It is a clear way to impact health outcomes.

But AC can't be the whole solution.

"One of the most important lessons emerging from heat adaptation research is that no single intervention is sufficient on its own," said Shweta Arya, senior project manager for smart surfaces at the American Public Health Association's Center for Climate, Health and Equity, which leads the association's work on health and climate action.

While 90% of U.S. households used AC in 2020, the latest year for which energy survey data is available, it's not a cure-all. It is vulnerable to power outages, and it contributes to outdoor warming via added electricity demand and heat expelled from vents.

Additionally, just because people have AC doesn't mean they can afford to use it. This is known as the "heat or eat" dilemma: analysis of US household data have consistently shown families limit food purchases and take on debt to pay AC-linked energy bills.

"In many cases, the primary barrier to stay[ing] cool indoors is not access to cooling equipment but the ability to pay monthly energy bills," Pilar Botana Martinez, a research scientist at Boston University's Department of Environmental Health, told Live Science.

Shade, rest and hydration outdoors

Evidence grade: Strong

Staying indoors to avoid the heat is one way to reduce the health impacts of climate change, "but this is not a practical solution for everyone, especially those doing demanding jobs in very hot warehouses, on construction sites, in agricultural fields," Barrak Alahmad, director of the Occupational Health and Climate Change Program at Harvard University, told Live Science.

Nearly one-third of U.S. employees — mostly men — have regular outdoor exposure as part of their job.

Some of the strongest evidence for strategies for keeping them safe on the job comes from studies of sugarcane workers in Central America, Alahmad said. A nongovernmental organization called La Isla Network has rolled out a strategy in which workplaces incorporate mandated rest, shade, hydration and sanitation breaks.

In data collected over six years, La Isla Network has shown that this strategy improves health by reducing negative outcomes such as heat-related kidney failure. Similar reductions in heat-related illnesses have been seen in California; Texas; and Guangzhou, China, when such measures have been implemented. And although these interventions have some training and supply costs, they increase productivity, the data shows, which makes them an easier sell for companies.

"The aim is to build systems that reduce risk and harm, increase productivity and provide a return on investment so that these efforts just become business as usual," Jason Glaser, CEO of La Isla Network, told Live Science.

Passive cooling

Evidence grade: Intermediate

Passive cooling reduces indoor temperatures without mechanical devices like AC. These strategies include modern technologies, such as reflective surfaces and roofs that reflect more sunlight and thus keep buildings cooler; shade structures and urban greenery; and traditional techniques, like courtyards, shades and ventilation.

"These are often low-cost material choices that can make a big difference in the safety and comfort inside a building and have a proven track record of performance [in lowering temperature]," said Kurt Shickman, senior fellow at the WRI Ross Center for Sustainable Cities.

These passive technologies also make AC more efficient, thus reducing costs and lowering demand for electricity on peak power days, Shickman said.

The evidence suggests cool roofs work at scale. A 2019 California modeling study predicted that state-wide adoption of this technology would halve the number of people exposed to heat wave conditions by 2050, while a 2024 study in London that modeled cool-roof deployment predicted that the technology could reduce heat-related deaths by up to 32% during heat waves.

Green spaces can also reduce heat exposure. In dense cities in Southeast Asia, the introduction of green infrastructure, such as trees lining streets and additional bodies of water, has been shown to reduce air temperatures by up to 4.7 F (2.6 C) and surface temperatures by 19.8 F (11 C).

Those interventions won't work everywhere, though, in part because strategies that reduce deaths from heat could worsen those from cold, and cold-related deaths are four times more common globally, a 2025 study found. So places that have both cold snaps and heat waves will need to think about those trade-offs before implementing such strategies.

City-wide heat warning systems

Evidence grade: Strong

Heat warning systems have been proposed to reduce heat exposure. There is evidence that some existing systems, such as New York City's, work to reduce death or hospitalization. But whether these systems are effective depends on how they're implemented.

"Effective systems do far more than issue a temperature alert" based on forecast high-heat events, Arya told Live Science ‪—‬ an idea other experts echoed. Instead, they trigger coordinated actions, such as reaching out to vulnerable populations, extending utility protections, and coordinating with healthcare systems for surges in the number of patients.

It's difficult to test such plans in controlled experiments, but researchers try by comparing a city before and after an intervention, or by finding comparable cities or regions that did or didn't implement a heat plan and assessing the plan's effectiveness. These "natural experiments" offer a comparison without having an alternative universe as a control group. Academics using such methods concluded in 2025 that heat exposure prevention plans led to a 25% reduction in deaths attributable to extreme heat across Europe.

Personalized alerts

Evidence grade: Strong

While most warning systems trigger when temperatures cross a threshold that's considered dangerous for an average person, Shickman said, "[i]n reality, people experiencing the same air temperature will have very different responses to it."

One solution could be to individualize attention. Shickman pointed to a pilot program by insurance company Emblem Health in New York, in which a trained artificial intelligence (AI) agent supported 17,000 people with personalized advice targeted to those with complex health or social issues. The intervention halved hospital admissions compared with a control group that didn't take part.

"We can go a step further and use technology to shift from generic, passive warnings to proactive ones that address individuals' needs," he explained.

Cooling centers

Evidence grade: Weak

A common strategy implemented during heat waves is the use of cooling centers — dedicated public spaces like libraries, schools, religious buildings or commercial locations where cooler air (often via air conditioning) offers respite.

Despite extensive adoption across the U.S. and internationally, there is very limited evidence that cooling centers reduce deaths or hospitalizations from heat exposure — likely because they're not visited much.

For example, a 2024 study into Virginia's cooling centers questioned the state's existing strategy because communities that had cooling centers also had higher numbers of heat-related illnesses. Surveying the field, a 2025 review from the National Bureau of Economic Research questioned "whether those who can most benefit from reduced heat exposure can or are willing to access cooling centers, and whether travel to centers can actually increase heat exposure relative to staying at home."

Wildfire smoke

Wildfire smoke is full of fine particulate matter known as PM_2.5. These particles are 30 times smaller than the diameter of an average human hair and can penetrate deep into the lungs and the bloodstream, thereby increasing the risk of ailments such as heart attacks, asthma attacks and adverse pregnancy outcomes.

PM_2.5 pollution contributes to tens of thousands of excess deaths every year in the U.S. And research suggests that wildfire smoke emissions could increase by 262% to 482% by 2055, depending on the level of carbon emissions.

Here's what has been shown to work against this threat.

Commercial air filtration

Evidence grade: Intermediate

Data repeatedly shows that air filtration — whether through commercial HVAC systems or even a fan with a filter taped to it — reduces indoor PM_2.5 exposure.

"For wildfire smoke, an important adaptation is cleaner indoor air, as simple as that may sound," Leonard said.

Staying indoors protects individuals from the worst PM_2.5 exposure. But a 2021 California study that used 1,400 air quality sensors showed that on days with nearby wildfires, smoke found its way into households, tripling PM_2.5 compared with days without fires.

Putting newer-grade filters (MERV 16 or higher) on commercial systems, however, can reduce PM_2.5 indoors by 81%, studies found. Similarly, portable air filters have been shown to reduce PM2.5 exposure in Montana offices, Seattle homes and Singapore apartments.

However, what's still unclear is the extent to which air filtration will reduce deaths or hospitalizations related to wildfire smoke. This is because we don't know whether interventions that make air cleaner in perfect conditions scale up; people may not replace their air filters, or they may use the portable ones only some of the time, for example.

Modeling of some air filtration measures, however, suggests that they could prevent 11% to 63% of the hospital admissions and 7% to 39% of wildfire-linked deaths.

Masks for outdoor smoke exposure

Evidence grade: Intermediate

Many people, including those who work in construction and other outdoor jobs, must venture outside during smoky days, and they need information and tools to protect themselves, said Gillian Capper, program manager at the American Public Health Association's Center for Climate, Health and Equity.

For example, these measures include "distributing N95 respirators and requiring smoke protection plans for outdoor workers," she said.

Modeling studies show that N95 respirators can reduce exposure to wildfire smoke by 90%, and a modeling exercise that used data from 2012 wildfires in Washington state showed that these masks decrease smoke-linked hospitalizations by up to 30%, compared with a group that did not use masks.

Land management

Evidence grade: Intermediate

The evidence to support a reduction in wildfires through land management is mixed. The idea is that by thinning forests, harvesting trees, clearing underbrush and doing prescribed burns to prevent unplanned conflagrations, we can reduce the risk of massive, uncontrolled wildfires.

"Reducing fuels today may help avoid larger, more severe fires and associated smoke impacts in the future," Micah Hahn, an associate professor of environmental health at the University of Alaska Anchorage, told Live Science. "But relatively little research has directly measured those downstream health benefits."

A 2022 modeling exercise led by U.S. Forest Service scientists compared four forest management scenarios ‪—‬ including actions such as forest thinning and prescribed burning — in the Lake Tahoe basin over the next century. It found that these measures reduced PM_2.5 particle levels as well as smoke-related illness and death, compared with fire suppression on its own. It also modeled the health impacts for one year (2039) and found reduced health costs tied to such management.

But the benefits plateaued with more land burns. Research from the southeastern U.S. shows that management can become a large source of PM_2.5.

Still, prescribed burns have an advantage over a spontaneously erupting wildfire, experts said. "With prescribed burning, one distinct difference is the ability to plan for smoke," Heidi Huber-Stearns, director of the Center for Wildfire Smoke Research and Practice at the University of Oregon, told Live Science, and to "know when and where it will likely affect communities as compared to the unpredictability of wildfires."

Smoke alerts

In theory, fire alerts, which use high-resolution air-quality data, could reduce smoke exposure, Laura Kate Bender, vice president of nationwide advocacy and public policy at the American Lung Association, told Live Science. Alerts would be paired with tailored guidance to notify people of dangerous smoke levels and to tell them when to take action.

Because these alerts are a fairly new idea, however, there's little data showing that such programs would reduce smoke exposure or related hospitalizations and deaths. That said, there’s evidence from other fields: a 2012 World Bank modeling exercise calculated that weather data and early warnings saved nearly 800 lives per year in Europe, and could save a further 23,000 in the Global South if systems were upgraded.

"The hurricane warnings are good examples to follow, as people do act on these early warnings", Kai Chen, faculty director at the Yale Center on Climate Change and Health, told Live Science.

Ultimately, the researchers we spoke with agreed that we need more data, which requires funding for further studies into which interventions are effective and can be scaled.

"We've put a lot of effort into understanding the impacts of climate change and related exposures," Alahmad said. "But there comes a point where we need to move from studying the impacts to looking at interventions and solutions and see what actually works out there."

How we evaluated studies

We categorized evidence as strong, intermediate, or weak. Here's the criteria we used to assess them.

Strong: Data shows a reduction in disease, hospitalization or death at a population level. Data comes from either randomized trials or quasi-experimental protocols. Sample sizes are robust enough to show a clinically meaningful effect.

Intermediate: Data shows an improvement in an intermediate proxy measure, such as temperature or particulate matter concentrations, which has been tied to negative health outcomes, and/or data relies on modeling to show improved health outcomes at the population-level.

Weak: Limited data exists, or the data that does exist does not show a strong protective effect.

Burning up — How can we adapt to a warming world?

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Time keeps getting away from us. It has a fraught relationship with our subjective experience — sometimes slowing down or dragging on; and at other times speeding up, with years seeming to fly by as we get older. Our brain cells are even known to distort our sense of time when we're tired.

In physics, time gets even more complicated, incorporated into theories of relativity — the experience of the clock's ticking being relative to the observer and their place in space — and entropy, which gives time its unidirectional flow. Meanwhile quantum mechanics indicates time can move both forwards and backwards, at least inside quantum systems.

In this excerpt from "On Time: The Physics That Makes the Universe Tick" (Princeton University Press, 2026), author and theoretical physicist Jim Al-Khalili looks at the possibility that time did not begin with the Big Bang — but if this outburst was just another moment, what was there before?

There is an alternative cosmological theory to the one that says the Big Bang marked the beginning of time itself, which was then followed by a brief period of rapid inflation of space. The alternative is known as eternal inflation. In this scenario, our universe was born as a small bubble in an infinite space that has been undergoing inflation forever.

So, rather than time beginning with our Big Bang, we should regard the Big Bang as an event that took place at some moment in time, in which our region of this infinite space suddenly stopped inflating and began instead to expand at a more sedate pace.

So instead of a brief period of inflation happening just after the Big Bang, in the eternal inflation theory it is the other way around, with the Big Bang marking the end of inflation in our part of space, creating our bubble universe outside of which inflation continues. The theory predicts there will be other big bangs happening elsewhere that give rise to other universes — possibly an infinite number of them — all forever separated from each other, and all being driven apart by the ever-expanding, rapidly inflating space outside of them. The totality of this infinite space is referred to as the multiverse, to distinguish it from the individual bubble universes.

Some physicists argue that such an idea falls outside of proper science, since we do not have a way of testing it. There are two other ideas worth mentioning on the matter of whether the Big Bang marked the beginning of time or not, both of which are alternatives to inflation theory. The first is that our universe is part of a repeating process called conformal cyclic cosmology'.

This idea, proposed by Roger Penrose, suggests that our universe is going through an infinite series of lives, or epochs, each of which starts with a big bang and ends with a universe in thermal equilibrium, filled only with evenly spread-out thermal radiation. The idea here is not, as you might expect, that the universe reaches some maximum expansion before collapsing down to a 'Big Crunch' that then marks the Big Bang of the next epoch, but rather because of a subtle geometrical idea called 'conformal mapping' that connects up the very dif­ferent end of one universe (cold and spread-out) with the birth of the next (hot and dense).

I will not say any more about this theory, in particular since it has been argued that it suffers from several flaws, such as the problem of conservation of information (similar to the so-called black hole information paradox) and the difficulty of reconciling the high entropy at the end of the old epoch with the low entropy of the new epoch.

A related hypothesis, which I admit I find aesthetically rather appealing, is known as the ekpyrotic universe model. The name is based on the Greek word ekpyrosis (ἐκπύρωσι), meaning 'conflagration', which refers to a cosmological model proposed by the Stoic philosophers of ancient Greece in which the universe cycles endlessly through fiery birth, expansion, and cooling, followed by contraction, reheating, and rebirth.

The name 'ekpyrotic universe' was devised by one of the modern theory's originators, Paul Steinhardt. The idea comes out of the highly mathematical world of string theory. Basically, the whole of our three-dimensional space (which as we know is really a part of 4D spacetime) forms what is called a 3D brane (a higher-dimensional generalisation of a 2D membrane, or sheet). This 3D brane of ours is floating in a higher-dimensional (4D) space, and the Big Bang is when it collided with a neighbouring brane (in a sense this would be another universe). This collision creates tremendous heat and radiation (the Big Bang) and sets off the expansion of our space.

At the same time, it is drifting away from the other brane that it collided with, but will eventually reach maximum separation from it before they are pulled back together, colliding again in a new Big Bang. Here I simply wish to stress that if this theory is right then there may not have been a beginning of time, and certainly not at the Big Bang.

Another cosmological model, which also does away with the need for inflation, as well as suggesting that the Big Bang was not the beginning of time, has been proposed by another of the originators of the ekpyrotic universe idea, Neil Turok. But this idea, known as the 'mirror universe' theory, is rather dif­ferent. It's a nice idea, and it certainly solves Loschmidt's paradox regarding the conflict between time symmetry and the second law of thermodynamics. Due to the time-symmetric underlying fundamental equations of physics, starting a system off at any arbitrary moment means that its entropy should increase equally into the past as it does into the future.

But this just doesn't make sense. If the system at all times before our chosen arbitrary moment has higher entropy, then starting from any of those earlier times should see the system decrease in entropy in order to reach its state at the original arbitrary moment. Therefore, it cannot be arbitrary; the system had to have been in a specially prepared state at that moment, the moment of the Big Bang. There would be no increase in entropy going backwards in time if that is when time started.

But what if there were a mirror universe on the other temporal side of the Big Bang, evolving in a direction we would consider to be towards the past? This is precisely what Turok is suggesting. What is neat (or convenient, depending on how much you like this theory) is that both sides of the Big Bang are completely separated from each other, with each seeing time pointing in the direction of increasing entropy. If such a mirror universe exists and contains intelligent life that has also hit upon the mirror universe idea, then they would think that our side was the one before the Big Bang in the same way we think that theirs is. As well as doing away with inflation, this idea also conveniently explains why there is more matter than antimatter in our universe because, guess what, the mirror universe would have it the other way round: What they call normal matter is our antimatter.

How seriously should we take these cosmological theories? Are they even proper science? Their proponents know they require some sort of empirical evidence to support their hypotheses, such as some imprint of a reality before the Big Bang frozen in our cosmic microwave background. For without observational evidence, these ideas will remain just theoretical curiosities.

Excerpted from On Time: The Physics That Makes the Universe Tick © 2026 by Jim Al-Khalili. Reprinted by permission of Princeton University Press.

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The patient: A 61-year-old man in India

The symptoms: The man went to an emergency department after fainting. He had felt nauseous just before the episode, which lasted about three minutes and was followed by a second fainting episode lasting about two minutes. He also had swelling around one eye.

His family told doctors that he hadn't shown any jerking movements, loss of bladder control or subsequent grogginess, which would have been telltale signs of a seizure.

What happened next: Because the man had fainted twice and had a history of heart disease, doctors first looked for problems affecting his brain and heart. An MRI of his brain, used to look for structural abnormalities that could explain the fainting, and an electroencephalogram (EEG), which records the brain's electrical activity, did not reveal a cause.

The man had persistently low blood pressure, the doctors observed, and this led them to move him to the intensive care unit. There, doctors carried out tests for infections and heart attack, but all came back negative.

Meanwhile, the swelling around one of his eyes spread to both eyes and then across his face, while his blood pressure continued to fall despite treatment with intravenous fluids.

The doctors probed further into the man's medical history and activities before the fainting episodes. They learned that he had applied an artificial hair dye two days before he became ill. Soon afterward, he developed itching on his scalp, neck and face. He self-treated with the allergy medicine cetirizine, an antihistamine, for two days. He also reported spending two to three hours outdoors in the sun each day after he'd applied the hair dye.

The diagnosis: Based on the man's recent use of hair dye, the itching that followed, his rapidly worsening facial swelling and his persistently low blood pressure, doctors concluded that he was experiencing anaphylaxis, a severe allergic reaction that can affect the whole body. The reaction can be life-threatening if left untreated.

The treatment: Doctors treated the man with epinephrine (also called adrenaline), a hormonal medication that rapidly reverses the effects of anaphylaxis. They also gave him antihistamines and steroids to help bring the allergic reaction under control, along with intravenous fluids to raise his blood pressure.

However, the patient's blood pressure remained dangerously low, so doctors continued giving him epinephrine through an intravenous drip for about 16 hours. Over the next three days of treatment, his blood pressure stabilized and the swelling in his face gradually subsided.

He was transferred to a general ward and treated there for another five days before being discharged. He was advised that he could have a similar reaction in the future and referred to a dermatologist.

What makes the case unique: Most allergic reactions to hair dye remain limited to the skin, causing itching, redness and swelling where the dye has touched it. Severe reactions affecting the whole body are uncommon, the man's doctors wrote in a report of the case.

The itching the man noticed shortly after applying the dye was likely an early, mild allergic reaction, his doctors wrote. That reaction later progressed to a much more severe one, they suggested, raising the possibility of a "biphasic" allergic reaction, an uncommon pattern seen in about 5% of patients with anaphylaxis. However, this remains only a possible explanation.

The doctors also noted that the man's prolonged sun exposure after he applied the dye may have intensified the reaction; they cited previous research that ultraviolet light can enhance the allergy-triggering effects of para-phenylenediamine, a common ingredient in hair dyes. In the report, the doctors did not identify the exact hair dye ingredient that triggered the reaction in this instance.

The case highlights the importance of asking about recent use of products such as hair dye when doctors evaluate patients with otherwise unexplained fainting, facial swelling or shock, the medical team concluded.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

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

Can you guess the diagnosis in these strange medical cases? Find out with our diagnostic dilemma quiz!

This eye-catching astronaut photo shows the point where an ancient Patagonian lake has been split by a peculiar land bridge, creating two contrastingly colored bodies of water.

Lake Pueyrredón (on the left in the photo) is the Argentine half of a roughly 40-mile-long (65 kilometers) glacial lake, which stretches across the country's border with Chile in Patagonia — a region in South America that is well known for its diverse range of geographic features, including mountains, fjords, deserts and rainforests. The Chilean half of the lake is known as Lake Cochrane (not shown in this image). Both halves hold crystal-clear water that is up to 1,600 feet (500 meters) deep, giving Pueyrredón a deep blue hue when viewed from above.

Thousands of years ago, a thick sediment barrier formed across the southern section of Lake Pueyrredón, creating a new body of water known as Lake Posadas. This smaller body, which is roughly 5 miles (8 km) long, has a lighter, teal color due to its shallow water and a large influx of sediment from a nearby river, according to NASA's Earth Observatory.

Other rivers from nearby hills have previously dumped large quantities of sediment along the western shore of Lake Pueyrredón (bottom of the photo), creating a trio of fan-shaped landforms, known as deltas, that increase in size from north to south (left to right in the photo).

Wind-driven currents and waves have pushed some of this sediment from the outer edges of the two smaller deltas, creating long, thin strips of land, known as sandspits, pointing down-current.

The strip of land separating Pueyrredón and Posadas looks similar to the sandspits. However, it is most likely a moraine — a barrier of sediment and larger rocks that formed along the edge of a hefty iceberg or long-lost glacier, according to the Earth Observatory.

Eagle-eyed viewers may be able to spot a narrow airstrip on the smallest delta (running almost parallel with its sandspit). While the area is largely uninhabited, it is popular with tourists, who travel to the lakes to camp, hike, fish and kayak, according to a local travel site.

Lake Posadas is also home to a unique island with a massive rocky arch (see below) that is also popular with tourists.

The two lakes in the astronaut photo sit within a large valley, which was carved by a massive ice sheet that once covered the area. The last remnants of this ice sheet are located in northern Patagonia, around 20 miles (30 km) west of Lake Cochrane, and have also been snapped from space by astronauts.

Patagonia is home to dozens of similar valleys and fjords that were carved out by the same massive ice slab. Around 210 miles (340 km) southwest of Pueyrredón and Posadas, a trio of ravines converge to create a rare configuration where a lake, river and glacier "touch" each other at a single point.

See more Earth from space

In the Kingdom of Benin, one of the oldest monarchies in West Africa, a traditional ruler known as an oba would commission a brass or bronze bust of their predecessor upon taking the throne. The bust of the past oba would then be set on an ancestral altar in the palace. But when the British Empire annexed the Kingdom of Benin into colonial Nigeria in 1897, the British looted thousands of African artifacts spanning the kingdom's seven-century history, and the country of Nigeria has asked that they be returned.

This particular bust is in the collection of the Cleveland Museum of Art (CMA), which acquired it from prominent French art dealer Louis Carré, who sold many of the artifacts looted from Benin to Western museums in the 1930s. This head of an oba ancestor, also known as "uhunmwun-elao" in the Edo language spoken in the historic Kingdom of Benin, is roughly 1 foot (30 centimeters) tall and was made from a copper alloy, using a lost-wax casting process that would produce one unique bust, then-CMA curator William Milliken wrote in a 1937 study.

Initially, CMA experts thought the ancestral head represented a princess, due to the layers of coral necklaces around the oba's neck and the thin braids hanging from the individual's temples. But the coral necklaces and the lattice-pattern beaded caps were actually potent representations of a ruler's power. The top of the bust is partly open, and it would have supported an intricately carved elephant tusk that recorded the oba's accomplishments and major life events.

Many of the surviving ancestral commemorative heads were created in the 15th and 16th centuries by the Igun Eronmwon, a hereditary guild of brass and bronze artisans that made objects for royalty in the Kingdom of Benin. According to the CMA, Benin royalty prized brass because it does not corrode. Much of the African brass was imported from as far away as Germany.

When British forces invaded the Benin royal palace in 1897, they looted thousands of metal plaques, sculptures of humans and animal figures, and royal and personal ornaments that have come to be known as the Benin Bronzes, even though most of the objects are technically brass, an alloy of copper and zinc. The British Museum holds the world's largest collection of Benin brass artifacts — over 900 objects — which Nigeria formally requested be returned in 2021.

Some institutions have begun repatriating this historic royal art back to its homeland. A group of German museums that collectively held over 1,100 of these objects transferred ownership of them to Nigeria in 2022. That same year, the Smithsonian's National Museum of African Art transferred ownership of 29 Benin Bronzes to Nigeria. And, in 2025, the Netherlands returned 119 Benin Bronzes to Nigeria. To date, however, the British Museum has not officially returned any of the Benin Bronzes in its collection.

There is also controversy about who should have ownership of these artifacts. In 2025, the Museum of Fine Arts, Boston returned two Benin Bronzes to Oba Ewuare II, the great-great-grandson of the last oba before the 1897 British invasion. Oba Ewuare II is the Oba of Benin and custodian of Benin culture.

A full catalog of royal artifacts looted from Benin in the late 19th century can be found on the Digital Benin project website.

For more stunning archaeological discoveries, check out our Astonishing Artifacts archives.

Can you put together last week's Astonishing Artifact?

With fall now upon us, many of us will be dusting off our binoculars and telescopes ready for the longer nights this season brings. Earlier sunsets mean more stargazing hours, and we'll start to see the return of some favorite celestial sights and deep-sky objects that we haven’t seen since before spring.

Fall is also an excellent time for casual stargazers, with the earlier evenings and cooler temperatures offering a comfortable compromise before we head into those freezing winter nights when we can't feel our toes. Don't worry if you're just starting out and don't have any gear yet, as many of this season's celestial objects are visible with the naked eye — and some are actually best viewed that way.

This September, October and November are great times to view the distant planets at opposition, catch several meteor showers and photograph far-flung galaxies and nebulas with your smart telescope. Plus, November brings the first full supermoon of the year. So, grab your telescope, your headlamp and a cozy sweater, and let's see what lies ahead.

Lunar & Planetary events

Neptune at opposition

Neptune reaches opposition on September 26 at 02:00 UTC, which is the best time to view it at its brightest, magnitude +7.8. Unfortunately, the full moon will somewhat ruin the party, and Neptune isn't particularly easy to spot at the best of times. That said, the opposition window lasts for several weeks, so waiting a couple of weeks to observe during the new moon week won't make any noticeable difference.

You'll need a good telescope to spot the big blue planet — at least a 6-inch aperture, although an 8-inch or bigger will give you the best chance. Make sure you have a good quality, high-powered eyepiece (something like a 6mm or 9mm) or a good Barlow lens to boost the magnification of your existing eyepieces.

But even with high magnification, Neptune will only appear as a small disc with a bluish hue — you won't see any cloud bands or surface features, because it’s just too far away. Still, it's worth trying to get a glimpse anyway.

Saturn at opposition

A week later, on October 4 at 12:00 UTC, Saturn reaches opposition, shining at magnitude +0.3. It will be easily visible to the naked eye, although to see Saturn's rings or any of its largest moons, you'll need a telescope.

The moon will be just below 50% illuminated and doesn't rise until past midnight, so you'll have a good portion of the late evening to observe Saturn while it's high in the sky before the moonlight affects visibility. Even though the rings are only partially tilted, you can still make out a lovely golden oval around the planet, and in larger telescopes you'll be able to spot the Cassini division. We recommend a telescope with at least 4 or 5 inches of aperture, and a good quality, high-powered eyepiece to observe the finer details.

Full supermoon

November 24 brings the first full supermoon of fall/winter, when the bright Beaver Moon will light up the skies, shining around 15% brighter than a normal full moon.

You can enjoy this moon without any gear whatsoever, but observing with binoculars or a telescope, or capturing its magnificence with a camera, makes the experience much more enjoyable.

Until then, you can catch the other full moons of the season on September 26 and October 26.

Uranus at opposition

The third planetary opposition of the fall belongs to Uranus on November 25 at 23:00 UTC. But like Neptune in September, the almost full moon will dampen its visibility, so we'd recommend waiting until the new moon week.

Like the other outer planets, you'll need a larger telescope with an aperture of at least 6 or 8 inches to view Uranus, alongside a good quality, high-powered eyepiece for the best views. These larger scopes gather enough light to distinguish Uranus's turquoise color, although you'll need to go even bigger if you want to see its brightest moons.

Meteor showers

Draconids

The first meteor shower of the season — and unlike most showers, which involve a lot of caffeine and an all-nighter, the Draconids are best seen in the late evening instead of the dead of night.

This meteor shower is active between October 6-10, peaking on the night of October 8-9. With the radiant point in Draco being highest at nightfall and the thin crescent moon not causing any interference, the best viewing hours are in the late evening before midnight.

These meteors are leftover debris from comet 21P/Giacobini-Zinner, and you can expect to see around 6-10 meteors per hour under ideal conditions.

Orionids

The Orionid meteor shower happens every October, when Earth passes through the trail of debris from Halley's Comet. In 2026, it's active between October 2 and November 7, with the peak occurring on the night of October 21-22. This shower brings between 10 and 20 meteors per hour under dark skies, radiating from the Orion constellation.

The waxing gibbous moon during the peak will add a fair bit of light pollution, but the moon will set between 03:12 am and 04:15 am depending on where in the States you're watching from, so you'll have a few hours before dawn to catch the darkest skies. You just need your eyes and clear, dark skies to see them, and a good astrophotography camera equipped with a wide-angle lens is perfect for capturing photos.

Taurids

The Taurids meteor shower comes in two parts. The first is the Southern Taurids, active between September 10 and November 20, peaking on the night of November 4-5 (during a thin waning crescent moon). The Northern Taurids come slightly later and are active between October 20 and December 10, peaking on November 12 (during an even smaller waxing crescent moon).

The hit rate is one of the lowest of all the meteor showers, with only around 5 meteors per hour. However, the Taurids are known for producing bright, slower-moving fireballs that linger in the sky — making them a particularly appealing astrophotography target.

Peak viewing time will be around midnight, when the Taurus constellation reaches its highest point in the sky.

Leonids

Radiating from the Leo constellation, the Leonids come from the dust and debris left behind by comet 55P/Tempel–Tuttle, which orbits the Sun every 33 years. They produce between 10 and 15 meteors per hour, and the shower period runs from November 6 to November 30, with the peak falling on the night of November 17-18.

The first quarter moon will set around midnight, making way for the best of the shower between midnight and 4 am in totally dark skies.

Star clusters and constellations

Pleiades (and Hyades)

A favorite among many stargazers, the Pleiades (M45), an open cluster known as the "seven sisters" in the constellation of Taurus, slowly returns to the night sky this fall. By October, it rises in the east a couple of hours after sunset and is visible from dusk to dawn from November. Although it's about 440 light-years from Earth, you can see it with the naked eye under dark conditions — even though it's usually just a faint, fuzzy patch — but binoculars or a telescope provide a much more impressive view.

As Greek mythology has it, the sisters — named Maia, Alcyone, Asterope, Celaeno, Taygete, Electra and Merope — were the daughters of the Titan Atlas and Pleione. The story is that Zeus transformed them into a cluster of stars to escape the relentless pursuit of the giant hunter Orion, who fell in love with the sisters and chased them for seven years. It seems he couldn't take the hint.

Look below the Pleiades, and you'll find their five half-sisters, the Hyades — an open cluster which makes up the V-shaped face of Taurus, the Bull.

The Pleiades are a fantastic target to capture with a smart telescope. If you want to stack multiple sessions across fall and winter, start in late November when they're high in the sky. You want an altitude of 50 degrees or higher, and ideally 60 degrees or more. The cluster itself is easy to capture, but the less atmosphere you're looking through, the more you can pull out that delicate blue nebulosity, which is what takes an image of the Pleiades from good to spectacular.

Another enemy of that lovely blue glow is the moon, so make sure you're imaging under completely dark skies with no more than around 25% moonlight. If you get a clear, moonless night, aim for 2-3 hours minimum to capture the faint nebulosity, and go for 3-5 hours for a really impressive image.

Pegasus

The best time to see the Great Square of Pegasus is during the fall evenings between September and January, with October offering the clearest and highest views in the night sky.

This asterism is a large, prominent square shape made up of four bright stars in the eastern sky — Markab, Scheat, Algenib and Alpheratz — with the latter belonging to the neighboring constellation of Andromeda. The square is said to make up the body of the winged horse, and the four stars range from about 133 to 670 light-years away from Earth. Point a pair of binoculars at them, and they'll reveal many more stars that are not visible to the naked eye.

Cassiopeia

Cassiopeia is one of the Northern Hemisphere's circumpolar constellations, so although it's technically visible all year, it's best seen during the autumn and winter months. Throughout the fall, it climbs higher and higher in the sky, reaching its upper culmination in mid-November, when it is best viewed between 9 pm and midnight.

Depending on its rotation in the sky, Cassiopeia appears as a "W" or "M" shape made up of five bright stars ranging from 19 to 425 light-years away and visible with the naked eye.

Cassiopeia was a vain, arrogant queen in Greek mythology, and after boasting that she and her daughter, Andromeda, were more beautiful than the Nereids, the gods placed her in the sky tied to her throne, where she spends half of the year upside down as punishment for her vanity.

The Owl Cluster

In addition to the constellation itself, there are some fun hidden objects within Cassiopeia that require binoculars or a telescope. The Owl Cluster (NGC 457) is a bright, open star cluster near the bottom-left star of the W shape, containing around 150 stars (although only 60 are identified as true cluster members), and is roughly 8,000 light-years from Earth. The blue and yellow "eyes" consist of the stars Phi Cassiopeiae (magnitude +5.0) and HD 7902 (magnitude +7.0).

You'll need a pair of astronomy binoculars to see it — go for 15x70 for a decent view, or 20x80 for an even better observation.

Caroline's Rose

Caroline's Rose (NGC 7789) is another open cluster in Cassiopeia, situated close to the last of the five bright stars in the "W" shape. Astronomer Caroline Herschel discovered the cluster in 1783 and it contains over 1,000 confirmed member stars, with estimates suggesting up to 3,000 potential stars.

It was named "Caroline's Rose" or the "White Rose" because its winding loops of stars and dark empty lanes resemble the petals of a cosmic rose, and it is estimated to be around 1.4 to 1.7 billion years old.

You can see it with a pair of binoculars under reasonably dark skies, but the best views will come from a telescope.

Deep-sky nebulas & galaxies

Andromeda galaxy

Our closest neighboring galaxy, Andromeda (M31), is about 2.5 million light-years from Earth and may one day collide with the Milky Way ("one day" being a 50/50 chance around 10 billion years from now, according to new research). But until then, we can easily make do with observing from afar with binoculars and telescopes.

October and November are prime evening viewing time, with the galaxy reaching its highest point between 7 pm and 11 pm. Under clear, dark skies, it's the most distant object visible to the naked eye, appearing as a very faint smudge — provided you know where to look. Binoculars provide a marginally better view of a somewhat larger, slightly brighter faint smudge — we've managed to see it with a pair of 8x25s under dark skies — but for the best views, you want a telescope.

It's a great first target for beginners using a smart telescope, with the prominent dust lanes revealing themselves after 30-60 minutes. If you want more detailed images of the faint outer arms, leave it for 3-4 hours. Moonlight can wash out the faint galactic arms and dust lanes, so if possible, choose a dark night with minimal light pollution.

In Greek mythology, Andromeda was the daughter of the aforementioned Cassiopeia. After angering the sea god Poseidon, Cassiopeia (who was not exactly Mother of the Year) chained Andromeda to a rock as a human sacrifice to the sea monster, Cetus, that Poseidon had sent to ravage their kingdom's coast. Andromeda was saved by Perseus, who she then married, and after her death, Athena placed her in the stars as a constellation.

Helix Nebula

The Helix Nebula (NGC 7293) is a large planetary nebula around 650 light-years away in the constellation Aquarius. Often called the "Eye of God", it has a striking eye-like appearance, and it features thousands of comet-like radial filaments and complex gas rings.

It stays relatively low in the southern sky, with September being the best time to view or photograph before it gradually sinks over the coming months. Moonlight will completely wash out its faint outer gaseous ring, so it's best to shoot during a new moon (or when the moon hasn't yet risen) to get the best image possible.

The best hours to capture it are between about 10:30 am and 2 am, when it's either rising or at its highest. This should get you a pretty decent standard image, but if you want more detail, try to capture it over several nights to pull in the faint outer nebulosity and stack the images.

Triangulum Galaxy

The Triangulum Galaxy (M33) is the third-largest in our local group of galaxies, behind the Milky Way and Andromeda. This stunning spiral galaxy — not to be confused with the Pinwheel Galaxy (M101), which is best seen in the spring — sits in the small Triangulum constellation about 2.7 million light-years from Earth and is a great astrophotography target.

Its peak viewing time is October to December, when its highest and clearest position is after dark in the late evening. Because it's so faint, you need a moonless night away from light pollution. The sweet spot for smart telescopes is around 90 minutes, but if you can shoot for longer or want to split your shoot across multiple nights, 2.5 to 4+ hours can bring out more detail in the core and spiral arm.

Heart and Soul Nebula

The Heart and Soul Nebula is a nebula complex consisting of two massive emission nebulas located about 6,000 to 7,500 light-years from Earth in the constellation Cassiopeia. They are primarily made of glowing ionized hydrogen gas, darker cosmic dust lanes and trace amounts of ionized oxygen and sulfur.

Like most other nebulas, they aren't visible to the naked eye, so you'll need a telescope or a long-exposure astrophotography setup to see them. The Heart Nebula (IC 1805) is, unsurprisingly, named after its heart-like shape, while its neighbor, the Soul Nebula (IC 1848), has a more irregular shape with large cavities made by stellar winds.

If you're imaging the Heart and Soul with a camera or smart telescope, a total integration time of 6 to 12 hours will provide you with the cleanest details and most contrast in the faint gas structures. That said, 2 to 4 hours will give you a good basic stacked image.

As Cassiopeia is at its highest in the fall, this is the best time to see and photograph it with the least amount of atmospheric interference.

Ghost of Cassiopeia

The Ghost of Cassiopeia, often referred to as the Ghost Nebula (IC 63), is a mixed reflection and emission nebula around 550 light-years away in Cassiopeia. Its eerie red glow is caused by its proximity to the nearby blue giant star, Gamma Cassiopeiae, which sits right in the middle of the constellation's distinctive 'W' shape. The star’s powerful ultraviolet radiation causes the hydrogen to emit a soft red glow, while the surrounding dust reflects the star's light in fainter blue hues.

Like the other celestial sights in Cassiopeia, autumn and winter evenings are the best times to see and photograph it due to its high altitude in the sky. As the nebula is so faint and elusive to capture, you can only see it with a smart telescope or a long-exposure astrophotography setup.

When it comes to integration time, the longer the better. Aim for 3-5 hours minimum, ideally 6+ hours if the skies allow, and avoid shooting during moonlight if you can.

It looks like a gigantic hole punched through a cloud, but this spectacular new image from the Hubble Space Telescope captures something more complicated: a cosmic cycle of destruction and creation, with one generation of stars tearing apart its birthplace while simultaneously helping a new generation form.

LHA 120-N44 (N44, for short) is a nebula that lies about 160,000 light-years away in the Large Magellanic Cloud, a small galaxy that orbits the Milky Way. From Earth, it appears in the constellation Dorado. This enormous, empty-looking region measures roughly 210 by 140 light-years. To put that into context, consider that Alpha Centauri, the closest star system to ours, is a mere 4.4 light-years distant. Thanks to that giant, hole-like appearance, this nebula is known as a superbubble, a cavity carved out by a cluster of hot, massive stars near its center.

Those stars are bent on destruction. Just like our star's solar wind, which creates auroras on Earth and defines the extent of the solar system, these stars' powerful winds blast material into space. Meanwhile, the most massive of these stars eventually explode as supernovas, pushing even more gas aside. The collective radiation from both these old and young stars carves the nebula's giant cavity.

So what happened to that expelled gas? Most of it has been pushed outward and compressed into a dense shell of gas and dust surrounding the superbubble. Within that shell, new stars are forming ‪—‬ so the same massive stars that destroy the gas cloud that created them also may help to produce their replacements.

This is known as "stellar feedback" — when massive stars heat, ionize and disperse the gas and dust around them, making star formation impossible in their vicinity. Meanwhile, their winds can squeeze neighboring gas clouds until they become dense enough to collapse under their own gravity and make new stars.

This Hubble image of N44 contains almost half a million stars, including those in the nebula and some lying along the same line of sight. About 30,000 of them are young stars yet to fuse hydrogen in their cores — the reaction that powers stars like the sun. With so many young protostars not yet hot and dense enough to become full-fledged main-sequence stars, N44 gives astronomers a rare opportunity to attempt an answer to what may seem like a very simple question: how long does it take to make a star?

In a multicat household, it's common to see one cat licking another. When some people see this behavior, known as allogrooming ("allo" means "another individual"), they assume it's a sign of friendship.

But is that really the case? Are there hidden, more complex reasons for why cats lick each other?

While research into allogrooming is ongoing, scientists have suggested different explanations for why cats lick each other, including some social reasons and some more practical ones.

Social bonding or social tension?

The historical view, based on observations of free-roaming-cat colonies, was that allogrooming is a sign of affection and helps cats create and maintain bonds with other cats in their social group, perhaps by creating a shared group smell.

But a 1998 study of 25 cats living together in an indoor-outdoor enclosure poked holes in this theory. The study found that aggressive behavior showed up in about 35% of allogrooming sessions, which suggested that allogrooming might not be about friendship. Instead, the authors proposed, it may help to defuse a tense situation in a confined space, where an actual fight would be too risky.

To investigate, Morgane Van Belle, a cat behavior scientist at Ghent University in Belgium, and her colleagues analyzed videos of allogrooming from 53 two-cat homes. They concluded that allogrooming may have different social functions, depending on the situation.

The team noticed that the cats sometimes licked each other while huddling together and copying one another's body postures. In these moments, allogrooming probably helps strengthen social bonds, the researchers proposed. Most licking was directed toward the ears; this may help cats relax because the skin there is rich in sensory nerve endings, Van Belle said. Allogrooming produces a relaxing effect in other animals too. For example, it lowers the heart rate in horses and triggers the release of feel-good hormones in monkeys.

They also noted that allogrooming sometimes led to friendly wrestling, in which the cats grabbed each other with their front legs and tumbled around. This suggests that allogrooming may serve as a signal to start play.

In other situations, however, the researchers noticed that allogrooming was followed by behaviors linked to conflict, such as turning the ears backward, pawing, and biting. In these cases, one cat would stand or lean over the other, and both cats showed subtle signs of stress like lip licking, head shaking or self-scratching.

Based on these observations, Van Belle's team think that allogrooming may be an "appeasement signal" in fraught moments that could lead to conflict or injury, for example, when one cat wants to take over a sleeping spot already occupied by another. They think it possible that the licking helps to calm things down and keeps a spat from turning into a real fight. Similar behavior has been seen in meerkats, where subordinate individuals groom dominant ones to placate them.

Yet because this licking often targets the neck — the same area cats bite during fights — it also may signal a subtle aggressive threat, the researchers suggested.

Hygiene and grooming

Van Belle and her colleagues think that, beyond sending social signals, allogrooming may help with hygiene. After all, it's often aimed at the head and neck ‪—‬ the areas that are "least accessible for the cat itself during grooming," Van Belle said. Allogrooming is thought to have a hygienic function in other species too. For example, ants achieve colony-level hygiene by grooming heavily infected individuals more, and primates concentrate their grooming on body parts the recipient can't easily reach. When it comes to cats, however, more research is needed. Van Belle's study did not measure parasites, infections or skin cleanliness to see whether such grooming actually reduces dirt or bugs.

Dr. Terry Curtis, a veterinary behaviorist who has studied how often allogrooming happens, also thinks cats might groom each other for hygiene reasons. She wonders whether feral cats, who likely carry more fleas than house cats, might have a different allogrooming pattern.

The explanations proposed by Van Belle and colleagues are reasonable but not definitive, Curtis said. Because so many factors can shape a cat's behavior, she's skeptical that researchers will ever be able to say with real confidence exactly why one cat grooms another.

After working as a veterinary behaviorist for 25 years, Curtis has concluded it is often impossible to understand what's going on in a cat's mind.

"Congratulations, you got a cat," she said. "Let the mystery begin.”

How much of a cat fan are you? Find out by taking our cat quiz!

Given that it's the closest planet to the sun, Mercury seems like it should be the hottest planet in our solar system.

However, at a blistering 900 degrees Fahrenheit (480 degrees Celsius), Venus tops Mercury's 800 F (430 C) highest surface temperature, despite being an average of 31 million miles (50 million kilometers) farther from the sun. So how can the second planet from our star be hotter than the closest planet to it?

It all comes down to reflectivity, atmospheric composition and geological history, experts told Live Science.

Totally different atmospheres

A planet's distance from its star is not the only factor that influences the planet's temperature.

"Distance tells us how much sunlight arrives at a planet, but it does not tell us how much is reflected … absorbed, how efficiently heat escapes, or how effectively the atmosphere transports heat around the planet," Stephen Kane, an astrophysicist who studies planetary habitability at the University of California, Riverside, told Live Science in an email. "Those properties can be just as important as distance, and sometimes much more important."

Mercury makes the case in miniature. According to Kane, the planet has essentially no atmosphere, so incoming sunlight strikes bare rock directly, heating it to extreme temperatures during the day. But with barely anything overhead to trap that warmth, Mercury radiates it straight back into space the moment the sun sets. As a result, nighttime temperatures plunge from roughly 800 F (430 C) during the day to about minus 290 F (minus 180 C) at night ‪—‬ a swing of well over 1,000 degrees, he added.

Venus tells the opposite story. Wrapped in an atmosphere that's roughly 90 times as dense as Earth's and consists almost entirely of carbon dioxide, Venus traps heat so effectively that its surface temperature barely changes at all, no matter where the sun happens to be, Kane explained.

A permanent blanket

Sunlight arrives at a planet mostly as near-infrared radiation and visible light, which pass through atmospheres consisting primarily of gases such as nitrogen, oxygen and carbon dioxide with relatively little trouble. Once the ground and lower atmosphere absorb that energy, though, they re-release it as infrared radiation, the kind of energy we feel as heat. Carbon dioxide happens to be excellent at grabbing and holding on to infrared radiation, Kane noted.

On Venus, the atmosphere is so deep and loaded with carbon dioxide that infrared energy leaving the surface gets absorbed and re-emitted over and over before any of it finally escapes into space. Some of that energy gets redirected back downward, Kane said, further warming the planet's lower atmosphere and surface. However, the heat isn't trapped forever, since energy conservation means that Venus must eventually release the same amount of energy it absorbs.

Notably, Venus doesn't actually soak up more sunlight than Mercury overall. Thick cloud cover reflects roughly three-quarters of incoming sunlight back into space before it ever reaches the ground, and only about 3% of the sunlight that arrives at Venus makes it down to the surface, Kane said. In fact, if that atmosphere and cloud deck were stripped away, a bare-rock Venus would actually run cooler than Mercury, since it would be receiving only about 29% as much sunlight from the start, he explained. It's the blanket, not the sunbathing, that makes Venus the hotter world.

Where the blanket came from

Venus' atmospheric blanket didn't spring into existence all at once, and how it formed is its own open question. Venus shows strong evidence of past and present volcanic and tectonic activity acting to smother the planet in greenhouse gases, Paul Byrne, a planetary scientist and associate professor of Earth, environmental and planetary sciences at Washington University in St. Louis, told Live Science in an email.

This volcanic activity has been so intense that Bryne describes modern Venus as sitting in a "post-runaway greenhouse" state, where its extreme heat has become a self-sustaining process regardless of what the planet's interior is doing at any given moment.

The heat isn't being generated from below; it's a consequence of the atmosphere Venus already has, locked in place by the same infrared-trapping effect described above.

Taken together, the experts' answers point to the same underlying lesson: How close a planet sits to its star is only the opening chapter of its climate story. What kind of atmosphere it has and how effectively that atmosphere holds on to heat are usually responsible for the rest.

See how well you know our planetary neighborhood with our solar system quiz!

To the untrained eye, Xiaoyu Shan's lab bench looked like a home gardening experiment gone bad: dishes filled with dirt — some that looked like mud pies and others that were bone-dry — and not a plant to be seen.

But those dishes held a warning. The dirt that Shan, a postdoctoral research associate in biology and biological engineering at Caltech, was studying contained soil microbes. And those soil microbes were exhibiting a concerning propensity: In dried-out soil, they were evolving to become more antibiotic resistant.

The study describing those findings, published in March, systematically showed that drought conditions could fuel the evolution of antibiotic-resistant bacteria. Most of this resistance is driven by humans' misuse of antibiotics, which spurs bacteria to evolve genes that help them ward off the drugs. But the Caltech study raised a new worry: As many places face increased drought conditions, climate change itself could act as a selective pressure that could supercharge the evolution of these drug-resistant superbugs.

"We can expect to have more resistant bacteria being selected for in certain places around the globe," said Dianne Newman, a Caltech microbiologist and co-author of the study.

Increased antibiotic resistance is just one way that climate change is likely to put new populations at risk of multiple types of infections.

And this increased disease burden will coincide with climate change scrambling supply chains, eroding nutrition and stressing our health in other ways.

"No individual metric really does justice to the overall risk and health and well-being of these multiple stressors being exacerbated all at once and compounding each other," said Marina Romanello, a principal research fellow at the Institute of Global Health at University College London.

Warm-weather disease

In the small mountain town of Bailey, Colorado, which lies at an elevation of 7,740 feet (2,360 meters), May often brings snowstorms that can blanket the ground in white even as the sun starts to bake the plains at lower elevations. But on Memorial Day 2026, the forest floor was dry and ticks quested their way along blades of grass, seeking a blood meal.

A mild winter in most of the country means ticks — and the diseases they carry — are a rising concern. In April, the Centers for Disease Control and Prevention (CDC) reported that emergency department visits for tick bites were at their highest for that month since 2017. That trend isn't a one-off, according to the CDC; as temperatures rise, insects and arthropods can survive longer in the year and farther north.

As a result, vector-borne illnesses such as Lyme disease (spread by black-legged ticks in the Ixodes genus) and West Nile virus (spread by mosquitoes) will become more common in increasingly northerly locations. Already, alpha-gal syndrome, which is not an infection but is transmitted by the Lone Star tick (Amblyomma americanum) and causes an incurable allergy to red meat, is also seeing a dramatic rise as the species expands its range across the Northeast. Positive tests for antibodies to the alpha-gal molecule have increased by 100 times between 2013 and 2024.

Right now, almost half a million people are treated for Lyme disease each year, and the CDC records more than 8,000 cases of other tick-borne diseases annually across the country. It's not clear how this will change as the climate warms. One 2022 study found major increases in Lyme disease only at levels of warming of 6.3 to 9.9 degrees Fahrenheit (3.5 to 5.5 degrees Celsius) by 2100, but that much warming that fast is now considered an implausible scenario. However, the researchers saw a huge amount of uncertainty in the numbers, given the number of variables that affect whether a spreading tick population will transmit more disease, such as how often people go outside or what steps they take to avoid tick bites. Tick-borne illnesses are likely also underreported, so even the true number of illnesses transmitted each year right now is unknown.

But ticks are responsible for spreading 90% of all vector-borne diseases in the U.S., so any trends in the suite of illnesses spread by ticks are likely to affect thousands to tens of thousands of people.

An even more ubiquitous bloodsucker, the mosquito, currently spreads only a few diseases in the U.S. The most common and most serious is West Nile virus, which mosquitoes catch from feeding on infected birds. As of Sept. 8, 504 cases of West Nile virus had been reported in the U.S. in 2026, with 363 of them affecting the central nervous system. And because fewer than 1% of West Nile cases progress to the central nervous system, those numbers likely represent a dramatic underreporting of milder cases, which can cause months of fatigue in some people, in addition to acute flu-like symptoms, such as fever, headache and body aches.

Mosquito-borne illnesses like West Nile are expected to spread more quickly in warming temperatures. Heat helps mosquitoes stick around longer during the year, much like it does for ticks. It also speeds up the transmission and replication of the virus inside the mosquito, since the insects are cold-blooded and thus their metabolism is ruled by the weather.

"Except for places that are already really, really warm, we should expect that the replication rate of the virus inside the mosquito will speed up," said John Drake, director of the Center for the Ecology of Infectious Diseases at the University of Georgia. "That shortens the generation time, and that means we expect there to be more transmission."

Even though mosquitos love water, climate-related drought could ironically nearly triple the number of human West Nile cases in the U.S. over the next 30 years from around 2,000 reported cases (according to CDC data) to between 5,000 and 6,000. That's likely because in drier conditions, more mosquitoes are infected, possibly because birds, the intermediate host of the virus, either congregate more closely with mosquitoes around water sources or breed less readily in drought, meaning the fraction of birds that carry the virus is higher than in more water-abundant times.

Mosquito-borne diseases long ago eradicated from the U.S. could also resurge with warming temperatures. The southeastern United States will become more prone to malaria and dengue fever transmission under all levels of warming; summer 2026 saw more than 40 locally-acquired cases of dengue fever in Florida. Public health surveillance and disease-control measures have largely stopped those transmission chains, but the likelihood is that society will have to pour more money into beating these diseases back again in future decades. For example, there are malaria vaccines approved for children, but currently, they are recommended only in areas where the illnesses are endemic. If malaria were commonly found in the southern U.S., millions of Americans might need vaccines, including susceptible adults.

"If we were to get endemic diseases like those in the U.S. again, it could become a huge burden and it could be quite costly," Drake said.

Disaster and disease

Flooding is another factor that's exacerbating vector-borne disease under climate change. As climate change worsens, extreme weather events will, too. Because warm air can hold more moisture, many areas will see increased episodes of heavy rainfall and hurricanes will become more intense.

"Flooding creates habitat for these mosquitoes," Drake said.

Disasters also spur the spread of other diseases that are usually quite rare in the U.S., such as leptospirosis, a bacterial infection that spreads from animals to humans via animal urine. Floodwaters may be contaminated by the bodies of drowned animals; in 2022, after Hurricane Fiora hit Puerto Rico, leptospirosis cases leapt by a factor of 3.6 to over 10 cases a week.

After Hurricanes Matthew and Florence in 2016 and 2018, respectively, North Carolina saw an 11% increase in emergency department visits for gastrointestinal illnesses. Black and American Indian residents were the most affected, likely because discrimination over generations has disproportionately pushed Black Americans and Native Americans to less desirable, more flood-prone land, the researchers found.

Cycles of precipitation, drought and subsequent dust storms can spur the spread of Valley fever, a fungal respiratory disease that causes an estimated 700 to 1,100 deaths per year, mostly in the U.S. Southwest. Valley fever is already on the rise, with cases in Arizona, one of the hotspots for the disease, doubling from about 64 cases per 100,000 people in 2005 to 145 cases per 100,000 people in 2022. As the West warms and dries, Valley fever is likely to spread from its stronghold in the Southwest and become endemic in Idaho, Wyoming, Montana, Nebraska, South Dakota and North Dakota, putting millions more people at risk.

The infectious disease risk from natural disasters tends to stack on top of other health problems stemming from these catastrophes. Flooded buildings can harbor mold that can worsen allergies, asthma and other respiratory illnesses. When major storms cause power loss, people turn to generators for electricity, which release pollutants linked to asthma. Though it's often hard to track the effects of these disasters, one study found that flooded regions after Tropical Storm Imelda in Texas in 2019 saw 10% more emergency department visits for asthma than nonflooded regions did.

Moreover, the threat to life and livelihood from these disasters can cause mental health conditions, such as post-traumatic stress disorder, Romanello said. The problems compound on each other, she said; already, she has heard reports from Africa about malaria outbreaks, fed by warming, and health workers struggling to reach the affected regions because flooding, also exacerbated by warming, has washed out roads.

"What is the most concerning aspect is that all of that is happening together, so we're seeing all of this risk being exacerbated at once," she said.

Antibiotic resistance on the rise

As Newman and Shan's work shows, as spots around the U.S. face new infection risks, existing treatments may become less effective. Their work showed that drought concentrated the natural antibiotics that bacteria make in the soil, making it harder for bacteria susceptible to the compounds to survive. As a result, the microbes with genes for antibiotic resistance did better. The problem for human health is that bacteria are very good at gene swapping, so these soil microbes can easily pass their antibiotic resistance superpowers to bacteria that infect people, their research showed.

"Gardening, breathing dust ‪—‬ that's how it happens," Newman said of human and soil bacteria coming into contact. "We are constantly encountering bacteria in our environment."

The researchers found an association between drought and antibiotic resistance reported by hospitals.

They aren't the only ones. A recent study on Salmonella, a bacterium that causes about 1.35 million cases of food poisoning each year in the U.S. alone, found that temperature and rainfall promote antibiotic resistance in this microbe. "Globally, climate change was linked to about a 10% increase in Salmonella resistance gene abundance," said study first author Zhen-Chao Zhou, an ecology researcher at the Chinese Academy of Sciences in Beijing. Other microbes show similar effects.

Meanwhile, warmer conditions help bacteria grow faster, adapt to stress and swap resistance genes, Zhou said, while drought concentrates them in limited water sources where they mingle freely. Climate-change-induced flooding can then, in theory, spread the resistant genes far and wide.

Combating the compounding risks requires both public health and climate mitigation approaches, experts say. Not only does the world need to cut greenhouse gas emissions, but people also need to use antibiotics more carefully, Zhou said; improve sanitation practices, such as sewage management, around the world so that antibiotic-resistant strains don't spread as easily; strengthen food safety; and expand disease surveillance. The public also needs to understand that climate change is a health issue, Romanello said.

"When we talk about tackling greenhouse gas emissions," she said, "what we're talking about is a sustainable livable future with healthy economies."

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The patient: A 55-year-old man in Bangladesh

The symptoms: The man went to the emergency room with severe abdominal pain that he said began five hours prior to his visit.

What happened next: During a physical examination, doctors noted that the patient's temperature and blood pressure were normal. His heartbeat was slightly elevated, at 110 beats per minute (bpm). (A typical resting heart rate for adults is 60 to 100 bpm.)

The man explained that one day earlier, an eel had "entered through his rectum accidentally," his doctors wrote in a report of the case. At the time of the encounter, the man was wearing a lungi — a type of long skirt often worn by Bangladeshi men — and he explained that the eel entered his lungi through the opening at the bottom and then wriggled into his anal canal.

He did not seek medical attention immediately after this happened, as he had hoped the fish would exit on its own.

When the doctors kneaded the patient's abdomen, it was rigid and tender. They ordered an X-ray, which revealed a dark, eel-shaped shadow on the right side of the abdomen.

The diagnosis: The X-ray showed a crescent-shaped gas shadow under the right part of the man's diaphragm and hinted that he had developed peritonitis — inflammation of a membrane called the peritoneum, which covers the abdominal organs. Peritonitis is usually caused by a bacterial or fungal infection, but it can also develop if fluids from other organs leak into the peritoneum.

If the condition is not treated quickly, it can lead to a life-threatening infection that can spread rapidly through the body.

The treatment: Doctors administered IV antibiotics, as well as fluids and anti-ulcer medications, which help repair injuries to organs' outer mucosal layers and prevent deeper tissue damage.

Due to the peritonitis, the doctors determined that the patient was at risk of septicemia, or "blood poisoning," in which pathogens invade the bloodstream. They decided to operate on the patient immediately and remove the eel via a laparotomy, a surgical technique that creates an opening in the abdominal wall and provides access to the pelvic organs.

After making an incision in the man's sigmoid colon — the S-shaped section of the large intestine adjacent to the rectum — the surgeons extracted the eel from the peritoneal cavity, the space surrounding the abdominal organs and encased by the peritoneum.

The eel measured nearly 2.2 feet (0.6 meters) long and was still alive. Perhaps, the doctors hypothesized, the eel was able to continue breathing by punching through the wall of the man's colon and squeezing into the peritoneal cavity, which contains a pale-yellow fluid that reduces friction between organs. This peritoneal fluid is mostly water, but it also contains glucose, electrolytes, proteins, enzymes, white blood cells and urea, a compound found in urine.

The surgeons then performed a sigmoid colostomy, creating an opening in the abdomen as an exit point for contents of the man's large intestine. In this way, they bypassed the damaged section of sigmoid colon to prevent leakage of fecal matter that could lead to further infection. Four days later, the man was symptom-free and was discharged from the hospital. The report did not document any follow-up visits.

What makes the case unique: Traumatic perforation of the intestine by foreign objects is uncommon, and cases involving live animals are "exceedingly rare," the authors wrote in the report. However, foreign objects often find their way into the human body through accidental ingestion or deliberate insertion into the rectum. Some deliberately inserted objects, such as vibrators, are designed for this purpose. Others are not; these have included chicken bones, light bulbs, metal rods, glass bottles and kitchen whisks.

Penetration of the colon by a live fish is an "unusual and scarcely documented event," the man's doctors added in the report. They noted one reference to such a case that appeared previously in scientific literature and involved a 50-year-old male patient in Hong Kong. In that case, the man knowingly inserted the eel — which measured more than 1.6 feet (0.5 m) long — into his rectum, allegedly in an attempt to relieve his constipation.

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

Can you guess the diagnosis in these strange medical cases? Find out with our diagnostic dilemma quiz!

In this excerpt from "The Carbon Wave" (MIT Press, 2026), author Leah Stokes, an associate professor of environmental politics at the University of California, Santa Barbara, looks at a hopeful moment in U.S. politics when climate change took center stage: when Rep. Alexandria Ocasio-Cortez and Sen. Ed Markey ramped up calls for a "Green New Deal."

In September 2017, a still­-unknown Alexandria Ocasio-­Cortez watched as Hurricane Maria devastated Puerto Rico. Electricity went down for months. Like thousands of Puerto Ricans, her grandfather died in the storm's aftermath. She could see how climate change was hitting her community harder than others.

And it wasn't just Ocasio-­Cortez's community: the year before, she'd traveled to Standing Rock, North Dakota, to see firsthand how the fossil fuel industry was harming Indigenous people. It was mere weeks after the 2016 election, and the resistance to Trump had found its center in a makeshift camp along the Missouri River. People had united to oppose an oil pipeline.

Serendipitously, the day after Ocasio-­Cortez left the protest, a progressive organization reached out to ask her to run for Congress. Moved by the activists at Standing Rock, she said yes. In 2018, she ran a long-­shot primary campaign in a Bronx district occupied by a ten-­term congressman in House leadership. Her platform included an idea that some had bandied about before, but no one had developed in earnest: a Green New Deal. As she told journalists that summer, "The Green New Deal we are proposing will be similar in scale to the mobilization efforts seen in World War II or the Marshall Plan. We must again invest in the development, manufacturing, deployment, and distribution of energy, but this time green energy." In June, she won the primary. Her election signaled the beginning of a broader shift: climate change was back on the political agenda.

That fall, the world's leading climate science organization, the Intergovernmental Panel on Climate Change —­ often called the IPCC —­ released a short report concluding that limiting warming to 1.5°C would require emissions to fall by almost half by 2030. The news ricocheted around the world, with headlines like "We Have 12 Years to Limit Climate Catastrophe." In my own neighborhood, someone printed a copy and stuck it in the free lending library, labeling it "important reading." The report changed how many people thought about the problem: it wasn't something we could deal with in 50 years; it was something we had to deal with today.

In the November 2018 midterm elections, two years into the first Trump administration, Democrats won big, paving the way for Nancy Pelosi to return as Speaker of the House after eight years as the minority leader. Days later, a group of young activists from the Sunrise Movement staged a sit-in at her office. Their bright yellow and­ black signs read "We have 12 years. What’s your plan?" referencing that scientific report.

Newly elected Representative Ocasio-­Cortez joined the action that day. She told the organizers they needed a clear ask and encouraged them to call for a Green New Deal. The idea broke through, sparking widespread coverage across the country. It was a new, hopeful vision for climate policy. These young people were not just talking about the climate disasters we needed to avoid —­ they were explaining how investments in clean energy could create good jobs. They were showing us the better world we could build together. If we only tried.

I watched these developments unfold in DC from my office by the Pacific Ocean and wanted to be a part of it. I wouldn't have to wait long. The Green New Deal held a force like gravity, pulling people into its orbit. By chance, I met some of the people tied to Ocasio-­Cortez at a conference and was invited to an early gathering to develop the idea into more detailed policy. By then, she'd released a framework for the plan with Senator Ed Markey of Massachusetts.

The meeting was held in March 2019, at a hip hotel in DC's Adams Morgan neighborhood, miles away from the Capitol. A wide swath of people were invited: youth activists, environmental justice leaders, political organizers, think tank wonks, and a few academics like me. It was a contentious meeting that opened with a protest, revealing fissures in the movement that would eventually grow into large cracks. Some people believed that frontline communities facing the greatest pollution burdens were not being adequately consulted or invited to participate in the event. At the time, I didn't understand these dynamics between the climate and environmental justice movements. I was just a political science professor trying to understand how I could make my work more practical and help get a climate law passed if we got the chance.

It was at that event that I met Varshini Prakash, the executive director of the Sunrise Movement. I’d seen her photo many times, standing in the middle of Pelosi's office with her dark red jacket over a black­ and yellow T-­shirt, surrounded by young people sitting on the floor. Four months had passed since the sit-­in, and Varshini had ricocheted to the center of the climate movement. But she was also a recent college grad in her mid-­twenties, feeling a heavy burden from the climate crisis and the work involved in fighting it. At one point during the meeting, she spoke frankly about the stress that was on her and other young activists and cried. I found her vulnerability moving.

The fact was, Varshini had already changed history. She'd given me, and millions of others, a sense of hope and possibility. It was her actions, alongside all the other organizers in the Sunrise Movement, that brought us together in that first DC convening, and in countless other meetings to come. She inspired me to believe that I could do something bigger if I tried.

Too often, the way we think about cause and effect is simplistic. We're fed a linear model that favors the immediate. One person is responsible for their own carbon footprint. One person only has one vote. One person can only do so much. From this perspective, standing against more than a century of fossil fuels running through the heart of our society, it can feel like there's nothing we could do to shake the system loose. We're too small. Mere drops. But drops in the ocean can make waves.

Excerpted from The Carbon Wave: A Story of Democracy, Parenthood, and the Race to Protect Our Planet by Leah C. Stokes. Reprinted with permission from The MIT Press. Copyright 2026.

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This iconic photo, captured by an American astronaut on board the International Space Station (ISS), shows a lengthy trail of thick smoke pouring across New York City in the immediate aftermath of the 9/11 attacks. A quarter of a century later, the image is as haunting as ever.

On the morning of Sept. 11, 2001, members of the terrorist group al-Qaeda hijacked four passenger airliners and crashed two of them into the twin towers — a pair of 110-story skyscrapers at the heart of the World Trade Center in lower Manhattan. The impact of these collisions, which occurred roughly 17 minutes apart, eventually caused both buildings to collapse.

Shortly after the second tower was hit, the third hijacked plane crashed into the Pentagon, the headquarters of the Department of Defense in Arlington, Virginia. Another attack — likely intended for Washington, D.C. — was thwarted when the passengers of a fourth plane fought back against their hijackers, causing the aircraft to crash near Shanksville, Pennsylvania. In total, 2,977 people were killed across the different attacks, according to the 9/11 Memorial and Museum.

NASA astronaut and ISS commander Frank Culbertson — the only American not on Earth at the time of the attacks — passed over New York City shortly after being told about what was happening back home. He photographed the thick plume of smoke blowing away from Manhattan, at an altitude of roughly 250 miles (400 kilometers) above Earth's surface.

If you look closely, you may be able to see what Culbertson described as an "odd bloom" around the base of the column of smoke rising from the towers. This is likely a sign that the image was captured "around the time of, or shortly after, the collapse of the second tower," Culbertson said.

Culbertson wrote several letters in the days following the attacks, sharing his unique perspective of the events. "It's horrible to see smoke pouring from wounds in your own country from such a fantastic vantage point," Culbertson wrote on Sept. 13. "The dichotomy of being on a spacecraft dedicated to improving life on the earth and watching life being destroyed by such willful, terrible acts is jolting to the psyche."

While in space, Culbertson learned that the pilot of the plane that was later hijacked and crashed into the Pentagon was his former flight school classmate Charles "Chic" Burlingame. When the ISS later passed over the Pentagon, the astronauts could see the large gash in the side of the building where the third plane had crashed. "Tears don't flow the same in space," Culbertson wrote while discussing his friend.

In 2017, Culbertson revealed that there was another striking thing he and the rest of his crew noticed in the wake of the attacks, according to Live Science's sister site Space.com. "One of the most startling effects was that within about two orbits, all of the contrails that are normally crisscrossing the United States had disappeared because they had grounded all the airplanes," he said.

However, there was one exception. The astronauts noticed a single contrail moving eastward across the Midwest. "That was Air Force One headed back to D.C. with President Bush," Culbertson said. It was a "very sobering" sight, he added.

See more Earth from space

When archaeologists with the National Museum of Denmark excavated a burial mound called Guldhøj (Gold Hill) in southern Jutland in 1891, they were surprised to find a well-preserved wooden folding chair similar to those known from ancient Egypt and Greece. But the Guldhøj folding chair was made in Denmark around 3,400 years ago and is the only completely preserved chair from the Bronze Age in Europe, according to the National Museum of Denmark.

The chair was discovered in the grave of a chieftain, who was buried in a hollowed-out oak tree trunk and wrapped in a cowhide. The man had been dressed in a wool cloak secured with a bronze brooch, two wool hats, woolen mittens and leather shoes. Among the offerings his loved ones left in the grave were a bronze ax and a bronze dagger, along with two ornate wooden bowls and a wooden box. But the folding chair was an unusual addition to the grave and was likely a marker of the man's extremely high status.

The frame of the Guldhøj folding chair was crafted from ash wood, while the seat was made from otter skin, only a fragment of which was preserved over the millennia. Patterns incised into the top of the wooden frame were inlaid with a black, tar-like substance to create a band of geometric decoration.

In a 1999 study led by archaeologist Kirsten Prangsgaard, researchers who examined the chair determined that it was made from two frames of wood, each about 13 inches (33 centimeters) tall. When the frames were put together at a 45-degree angle, the low chair or stool would have been around 9.5 inches (24 cm) off the ground. Originally, the chair frame was likely held together with bronze nails, which may have been removed before the seat was placed in the grave, according to the researchers.

Folding chairs may seem simple, but they were important pieces of furniture that signified the seated person was of high rank, and they were likely used in rituals or ceremonies, according to the National Museum of Denmark.

Archaeologists have found ancient folding chairs in this style in Bronze Age Egypt and Greece, where weather conditions are better for preserving organic material such as wood. The Guldhøj folding chair is not unique in Nordic countries; pieces of chairs have been found in other chieftain graves in Denmark and northern Germany, and a rare metal folding chair was even found in an early medieval woman's grave in Germany. However, it is the only completely preserved wooden folding chair from Bronze Age Europe, Prangsgaard and colleagues noted in the study. "The folding chairs thus seem to belong to the warrior graves of the Early Bronze Age," they wrote.

The similarity of the Guldhøj chair, which was made in Denmark, to chairs found in far-flung civilizations means that Bronze Age people were exchanging ideas through trade and gift giving, the researchers wrote. The chairs show a clear artistic connection between Bronze Age Nordic and Mediterranean groups. Another connection is the four-spoked wheel on the famous Sun Chariot from Trundholm, which mimics designs seen in the Aegean region.

Both the unusual folding chair and the wooden bowls buried with the Bronze Age chieftain in the Guldhøj mound "can only be described as rare objects of high prestige," according to the National Museum of Denmark.

For more stunning archaeological discoveries, check out our Astonishing Artifacts archives.

Can you put together last week's Astonishing Artifact?

It looks like a gigantic treasure chest left open among the stars — but instead of gold and jewels, this strange cosmic structure contains dozens of newborn suns. This new image from the James Webb Space Telescope (JWST) reveals the aptly named Treasure Chest, a colorful cloud of gas and dust in the Carina Nebula, one of the Milky Way's richest star-forming regions.

Located about 7,500 light-years away in the Southern Hemisphere constellation Carina, the nebula stretches roughly 260 light-years across and contains some of the most massive stars in our galaxy, as well as tens of thousands of young protostars. It's also home to the "Cosmic Cliffs," which appeared in JWST's first collection of science images, released in 2022.

The Treasure Chest is a cometary globule, an isolated cloud with a dense, dark head and a sweeping tail. Although such objects are named for their resemblance to comets, this one looks more like a wooden chest with its lid propped open and light spilling from inside.

JWST's Near-Infrared Camera reveals the source of that glow: a compact cluster of about 70 young stars embedded in the dust. The most massive one is a rare O-type star — extremely large, bright, and short-lived stars — measuring roughly 19 times as massive as the sun.

Astronomers estimate that the cluster is around 1.3 million years old, although earlier estimates suggested it could be as young as 100,000 years. Many of its stars are still surrounded by the gas and dust from which they were born. Over time, radiation from the cluster's stars will disperse that material, exposing stars that are currently hidden.

The Treasure Chest's unusual shape is also influenced by something outside the JWST image. About 39 light-years away, as measured across the sky, is Eta Carinae, the most luminous object in the Carina Nebula. Eta Carinae famously underwent its "Great Eruption" in the 19th century, when it briefly became one of the brightest stars in Earth's night sky. The system contains at least two stars, including one about 100 times as massive as the sun and roughly 5 million times as luminous. Together with the nearby Trumpler 16 star cluster, its intense radiation and stellar winds are blasting away the Treasure Chest's less-dense gas and helping to sculpt the cloud into its distinctive shape.

The Treasure Chest won't always look like this. Radiation and winds from the young stars inside it, combined with the assault from massive stars nearby, will gradually erode the remaining gas and dust. Eventually, the cosmic chest will disappear, revealing its true jewels — the stars within it.

For decades, engineers have been working to create smaller and smaller transistors to fit ever-larger numbers of them onto computer chips, all in the name of greater processing power. Now, in the age of artificial intelligence (AI), that effort has turned into an all-out race.

So how small can a transistor actually get? And is smaller even still the goal?

To understand the answer, first you need to know what a transistor is.

"If you take a computer or your mobile phone and you were to pry it open, you will see that there is a printed circuit board," Suman Datta, a professor of electrical and computer engineering at Georgia Tech, told Live Science.

On that circuit board are small, rectangular objects called chips, and inside each chip is a tiny piece of silicon. "And in that silicon, if you zoom in like a million times … maybe, if you're lucky, you will start seeing these tiny switches or transistors sitting etched into that piece of silicon," Datta said.

Each transistor is effectively a switch that turns on and off in response to jolts of electricity pulsing 4 billion times per second. Modern devices contain billions of transistors, and each one turning on and off in a precise orchestration to move and store 1s and 0s powers everything from Google searches and AI data centers to the device you're using to read these words.

The smaller the transistors are, the more can fit on each chip and the greater the chip's speed and functionality. So how small have they gotten so far?

"Researchers have built proof-of-concept devices in which a single atom controls the flow of electrons, although the rest of the device is still much larger," Anton Persson, an assistant professor at Chalmers University of Technology in Sweden, and Tara Peña, an incoming assistant professor at UCLA, told Live Science via a jointly written email. That means the switching part of a transistor has been made at the smallest scale physically possible, even though a complete device that small doesn't exist yet. New materials and approaches could make these devices even smaller. In a study published in June in the journal Nature Nanotechnology, Persson, Peña and colleagues used two-dimensional semiconductors made of tungsten disulfide, among other materials, to shrink nanoribbon transistors down to a channel width of 25 nanometers ‪—‬ about 0.00025 the width of a human hair.

Two-dimensional semiconductors are electrically active materials that are only one or a few atoms thick, and because electrical current can be controlled more precisely in such a thin layer, they allow for smaller transistors than traditional silicon does.

Over the next decade, they still expect silicon transistors to shrink, but more slowly than they did in the past, they said. "To go considerably smaller, we may eventually need to move beyond silicon to atomically thin materials, such as the two-dimensional semiconductors we study."

A host of considerations

Size isn't the only consideration; cost is important, too. It's enormously expensive up front to design and build a new chip. "We are as R&D-intensive as drug companies that spend billions of dollars developing one drug," Datta said. "It's a very similar business model."

There are also manufacturing factors to consider. "The often much harder step is producing billions of those transistors reliably, at scale and at a price that makes sense commercially," Persson and Peña said. "Something that works once in a laboratory does not necessarily work in a factory."

Another consideration is energy efficiency. "If I'm adding more and more transistors onto that little piece of silicon, and at the individual transistor level, they don't become more energy efficient … then when I go from, let's say, 10 transistors to 20 transistors, my power budget has to be doubled, all things being equal," Datta said.

For example, the latest Nvidia data center GPUs consume 1.4 kilowatts of electricity, and Nvidia's upcoming release is estimated to consume nearly a kilowatt more than that. Half of that is given up as waste heat, Datta said.

"So it's not just smaller, faster, cheaper, but also more energy efficient," Datta said. "You have to work on all the four vectors."

Is smaller still the goal in the age of AI?

Still, there is a limit to the physical space available for additional transistors, which is why engineers are turning to 3D designs — think taller instead of smaller.

"Instead of only making each transistor smaller, the idea is increasingly to stack transistors on top of one another so that more of them fit within the same chip area," Persson and Peña said. "That way, we can still make our electronics considerably more powerful, even if each transistor shrinks only modestly."

The quest for faster, more efficient chips is only getting more urgent with the explosive growth of AI. But smaller transistors and more powerful chips aren't just important for AI data centers; they also mean smaller, potentially cheaper consumer electronics.

"People certainly notice the consequences of smaller transistors," Persson and Peña said. "They can use less power and allow more computing power to fit on the same chip. That can mean faster electronics, longer battery life and lower costs. Historically, that combination has enabled today's smartphones to outperform room-sized supercomputers from decades ago."

So how small can transistors get? "We will do everything to make it as small as possible as long as we can control the physics," Datta said. "And as long as we can, we will find a way to make the economics work."

The Romans are well known for their aqueducts, which brought water to their cities and settlements.

These aqueducts sometimes ran for very long distances. For instance, the aqueduct of Valens, which brought water to the city of Constantinople (modern-day Istanbul), was 250 miles (400 kilometers) long, according to a statement from Johannes Gutenberg University Mainz.

The aqueducts also lasted a long time; their remains are some of the most prominent Roman architectural finds visible today. All of this demonstrates the Romans' engineering prowess. So how did the Romans build such large and long-lasting aqueducts?

Preparing the route

First, the Romans would select a source of water for the aqueduct, with springs being a popular choice. The aqueducts had to be designed so water would flow toward the city or settlement. The successful building of the aqueducts "was accomplished by an ever slight incline downwards from the spring to its end source," such as Rome, Ann Olga Koloski-Ostrow, a classics professor and chair emerita at Brandeis University in Massachusetts, told Live Science in an email.

Roman surveyors had to design a route carefully. "To choose a route with the necessary gradient, Roman surveyors would have either used the libra or the dioptra," Joseph Lewis, an archaeologist at the University of Cambridge, told Live Science in an email.

The dioptra was shaped like a disc with a sighting bar in the middle. It could be suspended from a stand, and the surveyor could look through the sighting bar at rods in the ground to help determine their elevations. "Surveyors would sight through the sighting bar toward surveying staves to measure differences to elevation," Lewis said.

The exact design of the libra is unclear, but we know that it had a plumb bob that was suspended in the air and the surveyor could compare it to rods in the ground to help determine differences in ground height. "Surveyors would set the libra up along proposed routes for the aqueduct and look forward and backward against calibrated staves," Lewis explained, noting that this allowed them to determine differences in ground height.

Building a long-lasting aqueduct

The Romans used a form of concrete that tended to last much longer than modern-day concrete. Roman concrete used pozzolan, an ashy substance, that was combined with lime and water to form a durable concrete that hardened when exposed to water.

"Roman concrete certainly played an important role, especially in bridges, arcades, and other structural elements," Giovanni De Feo, a professor of industrial engineering at the University of Salerno in Italy, said in an email.

But this wasn't the only factor that allowed Roman aqueducts to last such a long time.

"I believe their remarkable preservation results from a combination of factors," De Feo said. For example, the Romans were careful to select routes that followed stable geological formations.

Regular maintenance that, in many cases, continued into the Middle Ages also helped Roman aqueducts survive the test of time, De Feo noted. This means that they tried to avoid volcanoes and other landscapes that were unstable.

Aqueducts did not always run aboveground; sometimes, they had lengthy underground portions in areas where the landscapes made it difficult to place it aboveground. Some "aqueducts had hardly any stretches above ground outside the city, while others ran on arches for a considerable distance," Gerda de Kleijn, a researcher at Radboud University in the Netherlands, wrote in her book "The Water Supply of Ancient Rome" (J.C. Gieben, 2001).

As the water neared the city, it would sometimes go into pools that helped remove dirt and other visible pollutants. "Water would pool into the basin, sediment would sink to the bottom, then the water would continue from there on its course to the distribution tank," Harry Evans, a professor emeritus of classics at Fordham University, said in an email.

The number of workers required to build an aqueduct depended on its size and timeline for completion. The Hadrianic aqueduct at Athens, which runs for about 12.4 miles (20 km), could have been completed in 15 years by a team of around 500 workers, researchers estimated in a 2022 paper.

Maintaining the aqueduct

After an aqueduct was built, regular maintenance kept it in good shape. Cees Passchier, head of tectonophysics at Johannes Gutenberg University Mainz in Germany, has studied a Roman aqueduct at Divona in France. In a 2023 study, Passchier and colleagues found that carbonate would have built up on the aqueduct over time. Maintenance workers "partly scraped away" the carbonate before replastering the aqueduct, Passchier told Live Science in an email. At some other aqueducts, they wouldn't bother scraping but would "simply plaster over the carbonate without ever cleaning anything," he said.

A sizable number of workers would have been needed to keep aqueducts functional, but it varied based on the aqueduct's size. For "a small place like Divona, a workforce of a dozen people would probably have been enough," Passchier said. "We know that in Rome, there was a staff of a few hundred people to keep the aqueducts working."

Even after the Roman Empire collapsed, many of its aqueducts survived, as some were used and maintained into the Middle Ages and even into modern times. One of the aqueducts, the Aqua Virgo, built in 19 B.C., is still bringing water to Rome today.

From Augustus to Nero, see how much you know about ancient Rome's famous leaders with our Roman emperor quiz!

With only a couple of months to go before the harvest season for winter wheat in Colorado, the crop faced a whiplash: After a warm, dry winter, a cold snap plunged the plants into freezing weather for 12 hours, and temperatures soared to nearly 90 degrees Fahrenheit (32.2 degrees Celsius) two days later. When the final harvest numbers were tallied in July, 73% of the crops were in poor or very poor condition. According to early estimates by Colorado Wheat, 2026's winter wheat crop was the smallest in the state since 1965.

Pick a crop, any crop, and you'll hear a similar story: Extreme weather and climate change are rocking the food supply. The warming climate makes food less nutritious, threatens crop survival, and triggers tipping points that would upend farming as we know it.

The impacts will be felt most intensely in less-developed regions of the world, where many people can't afford imported food and climate-related famines and nutritional scarcity are already happening.

But the U.S. is facing big changes to its food systems too, and no one is immune. Humans have overcome looming agricultural disasters before, but experts say the challenge should not be underestimated.

"There are real food security and nutrition concerns," said Andrew Hultgren, an environmental economist at the University of Illinois, Urbana-Champaign, "especially under these high-warming futures."

Food is becoming less nutritious

As the planet warms, food crops are expected to become less nutritious. That's because, due to plant biology that's not yet fully understood, crops grown under higher levels of carbon dioxide are deficient in zinc, protein, magnesium, iron and other micronutrients. Crops are already less nutritious than they were in the 1950s, but this is partly due to breeding decisions that prioritize yield over nutrition. The carbon dioxide deficiencies will exacerbate this nutrition decline.

The global monthly average concentration of carbon dioxide in the atmosphere is now over 420 parts per million (ppm), well over the preindustrial average of 280 ppm. By the end of the century, those levels will increase to at least 550 ppm in all but the most optimistic scenarios.

That will mean an additional 175 million people will be zinc deficient and an additional 122 million people will be protein deficient by 2050, a 2018 study found. Zinc deficiency has consequences for immune and skin health and may lead to poor growth in childhood; protein deficiency can also cause stunted growth as well as fatigue, muscle weakness and stress fractures. Those figures account only for the effects of carbon dioxide. A cascade of climate shifts and extreme weather may also affect the number of nutrients (and calories) available to the world.

The threats are myriad: Rising sea levels may inundate farmland and lead to saltier soil in coastal regions where, for example, rice farming is common. Soil salinity can make it impossible to grow crops in some regions. Droughts, heat waves, storms or temperature swings like those seen in Colorado this year might take out certain crops in particular places, leading to year-by-year price spikes or shortages. In the U.S., the results might look a lot like the recent egg shortages triggered by bird flu; temporarily empty shelves, price spikes, or even restrictions on the amount a customer can purchase in a visit for an affected food.

Climate shifts that harm pollinators and fuel the spread and introduction of plant pathogens such as harmful fungi will also likely reduce crop yields.

Areas that depend on the ocean for food are also facing steep challenges, due to both ocean acidification and the degradation of coral reef ecosystems, which are sources of food for many coastal communities and form much of the base of food chains for the larger fish people eat.

Hotter weather also affects food safety, said Christopher Golden, a professor of nutrition and public health at the Harvard T.H. Chan School of Public Health.

"Increasing sea temperature and increasing sedimentation within seas could lead to harmful algal blooms or increasing food poisoning events from temperature-related food spoilage," Golden said. Algal blooms can contaminate shellfish like oysters or scallops with neurotoxins that can sicken and kill people who eat them. Food spoilage is a concern in regions such as Madagascar, where catches are brought ashore and readied for consumption in the open air.

Meanwhile, fish may move poleward to avoid the hottest sea temperatures, leaving the most vulnerable regions ‪—‬ such as Southeast Asia, the Caribbean, Africa, Central America and the Pacific ‪—‬ with fewer fish in their waters. How bad this looks depends on the extent of the climate swings, with research suggesting that without any mitigation, fishers could see their catches decline by 58% to 92% off small islands in the Pacific and by 70% to 86% in Southeast Asia. This would drive food insecurity and malnutrition in those regions. The U.S. will likely face impacts too, as most of its seafood is imported from subtropical or tropical waters elsewhere.

There may be shifts in trade networks that lessen the blow for U.S. consumers, Golden said, but it's hard to predict. Some possibilities include "price shifts or trade shifts that lead to changing dietary patterns or more shelf-stable and heavily processed items that we know aren't good for your health," he said. In other words, less fresh-caught snapper and more potted meats.

Changing foods on the table

Individual producers are adapting, sometimes in ways that may not be immediately obvious to consumers. "Climate change is bad in that it's a slow-moving wave," said Elizabeth Wolkovich, a professor of forestry at the University of British Columbia. "You don't really notice that it's shifting underneath you and that the apple you eat isn't the apple your granddaughter will eat."

On that note, growers in the Pacific Northwest and U.S. Northeast will face challenges getting apples to lunch boxes around the world. Fewer cold days and more extreme-heat days will likely reduce apple yields by affecting how and when trees go dormant and bloom. Because it takes five or more years to establish fruiting trees in new regions, this could mean a reduced apple supply and higher prices.

Today's smooth arabica coffee (Coffea arabica) varieties may get harder to find and more expensive as climate change forces coffee growers out of many of the places they used to farm and droughts reduce supply. Earthier, more bitter robusta coffee beans (Coffea canephora) do better in warming temperatures, but even those beans could struggle with increasing seasonal variability caused by climate change.

Climate has already shifted wines in favor of less-acidic and higher-alcohol varieties, Wolkovich said, but it's happened slowly enough that, unless you're a connoisseur, you may not have noticed. Wine lovers can expect more changes: Wolkovich has found that the varieties of wine grapes that growers can produce will shift with climate change. Wildfires in grape-growing regions like California can also produce an unpleasant acrid and smoky flavor in wine.

And it's not just flavors that will be affected. U.S. dairy cattle breeds originated in cool and cloudy Northern Europe, and their milk output goes down as temperatures climb. Such heat stress reduced annual milk yield by an average of 1% a year between 2012 and 2016 alone, and heat-related losses are expected to balloon by 30% by 2050.

Americans have long been drinking less milk from the glass, but their demand for yogurt and cheese is rising, said Jared Hutchins, an assistant professor of agricultural and consumer economics at the University of Illinois Urbana-Champaign and first author of the study on milk yield. Those products depend heavily on the fat and protein content in milk, which is the first thing to drop when cattle are hot. "Fat and protein are what deliver the cultured dairy products that are in high demand," Hutchins told Live Science.

The story repeats itself across agricultural products, Hultgren said. "For each degree of that global temperature rise, caloric output [from crops] drops by 120 kilocalories or U.S. calories per person per day," he said, "which is about 4.5% of a person's daily recommended caloric intake."

That calculation, published by Hultgren and his colleagues in the journal Nature in 2025, already accounted for adaptations that farmers can make to reduce crop losses. Without those adaptations, the number would be over 30% higher, he said.

Reductions in available calories will translate to food shortages in vulnerable places, such as the Horn of Africa or India, said Marina Romanello, executive director of a multinational research project that tracks the impacts of climate on health at University College London. In North America, "it would feel like inflation," Hultgren said ‪—‬ yet another factor driving up grocery prices.

Worst-case scenarios

For farmers, the year-by-year uncertainty of climate change is a problem. Will this year bring drought? Will there be a sudden storm or flood that will wash away the spring crop? Should they take a risk on a new heat-resistant plant or agricultural technique?

Similar uncertainty haunts the long-term forecast. Climate tipping points can lead to sudden, irreversible changes in the system. For agriculture, one of the scariest tipping points is the potential collapse of the Atlantic Meridional Overturning Circulation (AMOC). This pattern of ocean currents brings warm surface water north from the equator and circulates cold water south, warming Northern Europe and the northern parts of North America and cooling the Southern Hemisphere.

If this current were to collapse, northwestern Europe would cool dramatically, with studies suggesting that London could see temperature lows of minus 4 F (minus 20 C) ‪— ‬colder than the city's lowest temperatures on record. Precipitation would decline across Europe, leading to drought. Meanwhile, in the Amazon, the wet season could become the dry season and vice versa, said René van Westen, a climate researcher at Utrecht University in the Netherlands who has studied the impacts of an AMOC collapse.

On the other hand, if the AMOC doesn't collapse, London is expected to warm by 4.9 F (2.7 C) and see 15% to 18% more precipitation, depending on the season. The uncertainty in these predictions makes preparations difficult. There is still a lot of controversy over whether the AMOC will collapse and, if so, when. Should farmers plan for England to become increasingly toasty, or should they expect it to be plunged into a little ice age?

AMOC-related changes will take decades to centuries to unfold, even with a total collapse, van Westen told Live Science. But even so, they would require a total rewriting of agriculture in Europe and the northeastern U.S. "It will be very challenging to adapt to such a scenario," he said.

That doesn't mean a collapse of the world food system is inevitable. Farmers are already adapting to the early impacts of climate change by scaling back water-hungry crops in drought years and, in some places, testing new, heat-resistant varieties of crops in an attempt to stem the losses.

And humans have overcome looming disaster in agriculture before: In the 1950s and 1960s, new varieties of rice and wheat, along with the availability of synthetic nitrogen fertilizers, spurred the "Green Revolution," tripling the world's yield of cereal crops while expanding farmland by only 30%. Similar innovations could limit hunger even as the world warms.

But the biggest way to mitigate these impacts is the most obvious one. While Hultgren and his colleagues found that adaptation could cut caloric losses under climate change by 30%, mitigating warming by reducing emissions today could slash them by half. Similarly, the AMOC is on a path toward weakening, van Westen said, but as long as humans slow the pace of climate change, the current can recover.

"If you are cutting your emissions," van Westen said, "you can lower your risk."

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Do you know where pumpkins and blueberries come from? Find out with our fruits and vegetables quiz!

The patient: A 47-year-old woman in Canada

The symptoms: The woman underwent a lung transplant to treat interstitial lung disease, which involves harmful inflammation and scarring of lung tissue. While recovering in the hospital, she ate a bowl of breakfast cereal, which activated a nearly two-hour episode of flushing, itching, shortness of breath and low blood pressure.

This severe, life-threatening allergic reaction is known as anaphylaxis. A report of the woman's case does not mention specific treatment she received for this reaction, but it notes that it resolved after two hours.

(Treatment for anaphylaxis involves epinephrine (also called adrenaline), and it can also require antihistamines, cortisone, oxygen and beta-agonists, such as albuterol, which help improve breathing.)

What happened next: The woman experienced the same symptoms in the weeks after being discharged from the hospital — after eating a coconut cream pie and after having an almond candy bar.

The diagnosis: Two months after her lung transplant, the woman underwent a skin-prick allergy test, which revealed a sensitivity to peanut and pine nut allergens. She did not have an allergic response to tree nuts, such as the almonds in the candy bar, nor to coconut. None of the foods that triggered her symptoms were known to contain peanuts, but none were certified as peanut-free, either.

Notably, the woman's lung donor had been a 12-year-old boy with a known peanut allergy but no history of anaphylaxis. Her doctors theorized that the transplanted lung tissue contained immune cells from the donor that were sensitized to nut allergens.

The treatment: The woman did not receive a specific treatment to get rid of this new allergic response. However, the sensitivity subsided in follow-up skin-prick tests, and they had disappeared completely by a year after her surgery. She ate peanuts in a supervised setting a few months after the one-year mark and had no reaction.

The doctors reasoned that the sensitized immune cells from the donor must have cleared from her body.

What makes the case unique: Only one other case of peanut allergy following a lung transplant had been documented before the woman's case was published in 2011.

Scientists had only recognized the risk of allergies being passed from organ donors to recipients a little over a decade before the report, according to a 2025 review of such instances. Doctors had previously reported allergy transfer linked to bone marrow transplants, which makes sense given that bone marrow produces immune cells. But the first known donor-acquired allergy from a solid-organ transplant was observed in 1997 following a combined kidney-liver transplant from a donor who was allergic to peanuts.

The authors of the 2025 review noted that donor-acquired allergies are more commonly associated with lung and liver transplants than with transplants of other solid organs. That could be because these organs are rich in a type of immune cell that produces allergen-specific antibodies, called B lymphocytes.

Other potential culprits for donor-acquired allergies are mast cells and basophils, two types of immune cell that bind to those allergen-specific antibodies. The cells hold onto the antibodies, and when they encounter an allergen, they release the inflammatory compounds responsible for anaphylaxis.

In the woman's case, a blood test for peanut-specific antibodies came back negative. This suggested that her body was not continually generating the antibodies. That could serve as possible evidence that her reaction was caused by antibodies bound to mast cells or basophils within the donor tissue, rather than antibodies produced by lymphocytes.

That said, the woman's reaction to the skin-prick test could imply that lymphocytes were still involved in the allergic reaction, the doctors added, as they did not know whether mast cells or basophils could migrate to the skin the way circulating antibodies could.

Regardless of the cell type behind the woman's peanut allergy, the sensitivity faded after a year, consistent with other cases described in the 2025 review. Still, the review authors called for better donor allergy labels to inform allergy testing and treatment for organ recipients. The doctors in the case report came to a similar conclusion, noting that detailed donor allergy histories and skin-prick testing after organ transplant could help identify donor-acquired allergies.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

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

This striking satellite snap shows a series of ghostly green lakes that merged into a single murky entity after several years of unusual weather in the Australian outback.

The entwined lakes are located in Barkly Tableland, an area within Australia's Northern Territory, which lies between the states of Queensland, South Australia and Western Australia. The largest section of the conglomerate is Tarrabool Lake (on the left side of the photo), which stretches around 55 miles (90 kilometers) across at its widest point. It is dark green due to the dense vegetation and algae in the water.

The smaller half of the merged lakes (on the right side of the image) is made up of three lakes: Lake Sylvester, Lake Corella and Lake Deburgh. This section has a paler and chalkier hue due to high levels of suspended sediment. This is likely because the lakes have overflowed and mixed together, whipping up the dust and topsoil that once surrounded them. (Several other, smaller lakes of various sizes and shades of green can also be seen throughout the image.)

All of these lakes are ephemeral, meaning they have no constant inflow or outflow of water, much like most of Australia's other lakes. As a result, they almost completely dry out during prolonged periods of sunny weather, as high temperatures cause the water inside them to evaporate, and then reappear as heavy rainfall refills the basins.

However, across the two years prior to this image, there was so much rain that the lakes never dried out. Instead, they continued to grow year over year, as you can see from additional satellite imagery (see below), which shows the same area between 2022 and 2024.

The Northern Territory's rainy season lasts between October and April. Both the 2022-2023 and 2023-2024 rainy seasons, which preceded the 2024 satellite photos, were ranked among the top 10 wettest since 1990, according to NASA's Earth Observatory, which released these images.

Although this is extreme, it is not that surprising, considering that annual rainfall in the Barkly Tableland rose by around 14% between 1989 and 2018, according to a report from the Australian Bureau of Meteorology. This is likely due to the effects of human-caused climate change.

On top of the general increase in rainfall, Tropical Cyclone Megan dumped a massive amount of rain on the region in March 2024. The resulting flash flooding was so great that fish were seen swimming across a nearby road, Australia's ABC News previously reported.

In the winter, Tarrabool Lake and Lake Sylvester are important breeding sites for birds, including the straw-necked ibis (Threskiornis spinicollis) and the Australian pelican (Pelecanus conspicillatus), and BirdLife International lists both lakes as important bird areas. At its fullest, Tarrabool Lake also floods the surrounding Eva Downs Swamp system, creating Australia's largest wooded swamp.

See more Earth from space

At the beginning of the 20th century, a German art collector acquired dozens of artifacts from a Russian-led excavation of an ancient Hun settlement in Crimea. The most spectacular piece of the collection was the Crown of Kerch ‪—‬ a garnet-studded, gold diadem featuring stylized birds of prey.

The artifact, which is now on display at the Neues Museum in Berlin, is made up of three gold-covered, bronze plaques and more than 250 gem-studded cells. According to the museum, the crown was discovered in the grave of a high-status woman buried in the ancient city of Pantikapaion on what is now the Kerch Peninsula of Crimea.

The band of the rare gold diadem is roughly 1.7 inches (4.4 centimeters) tall and is associated with the fearsome nomadic warriors known as the Huns, who moved west from the Don River in what is now Russia in the late fourth century A.D.

Pantikapaion was founded as a Greek colony in the sixth century B.C. but was conquered by the Huns in the late fourth century A.D. A large necropolis with as many as 2,000 burials was excavated at Pantikapaion in the early 20th century, but only a handful of artifacts and skulls were saved from the excavation. Pantikapaion was incorporated into the Byzantine Empire in the sixth century by Emperor Justinian I.

The Crown of Kerch features two stylized heads of birds of prey, likely eagles, flanking a central floral motif. Round, green gems mark the birds' eyes. These birds likely represented power and authority among the Huns and other groups, according to the museum, and they were a popular symbol on jewelry and accessories of the time. Similar birds of prey have been found on Visigoth women's jewelry in Spain from the sixth century, for example.

German archaeologist Joachim Werner wrote in a 1956 study that the Crown of Kerch was found in a burial chamber near the skeleton of a woman with an artificially modified skull. Although the woman was buried with the diadem, Werner believed that these items were not just used for grave goods, and that high-status Hun women regularly wore the accessory during life, possibly with a cloth cap or veil attached.

Around two dozen examples of similar gold diadems have been discovered to date. This suggests that the Crown of Kerch is not technically the royal insignia of a queen but rather a diadem worn 1,600 years ago by a member of the ruling Hun elite.

For more stunning archaeological discoveries, check out our Astonishing Artifacts archives.

Can you put together last week's Astonishing Artifact?

In this single Hubble Space Telescope image, tens of thousands — possibly millions — of stars bound tightly by gravity sparkle as one. This is NGC 6723, a glittering globular cluster about 27,000 light-years away, in the constellation Sagittarius.

Also known as the Chandelier Cluster, this swarm of stars is one of about 150 known globular clusters that orbit in the halo of the Milky Way, though others may remain hidden behind thick cosmic dust or crowded star fields at the galaxy's bright core.

Globular clusters like NGC 6723 are among the most ancient structures in our galaxy. What baffles astronomers most is the age of the stars within them. These clusters often contain stars older than 10 billion years, with some dating back almost to the beginning of the universe itself 13.8 billion years ago. They likely formed early in the history of the Milky Way, billions of years before the thin disk of stars where the sun now orbits took shape.

It was once thought that all stars inside a globular cluster formed at the same time, from the same material, during a single burst of star formation. If that were true, the stars would have the same age and chemical composition.

However, Hubble's view demonstrates that this is not the case. The cluster is densely packed at the center, where many bright-blue stars appear concentrated, while orange stars are more prominent toward the edges. Blue stars are younger than orange stars, suggesting that globular clusters can have complex histories, with different populations of stars and subtle chemical differences among them.

Hubble first observed NGC 6723 in visible and near-infrared light as part of a major survey of 65 globular clusters in 2013. It found that massive stars sink toward the center of a cluster, while lower-mass stars drift outward. In 2013 and 2014, Hubble studied NGC 6723 to search for small chemical differences between stars and to measure the spread of ages of stars within the cluster. Two epochs were found, with the second burst of stars happening about 634 million years after the first.

One leading idea is that globular clusters formed when enormous gas clouds collapsed rapidly in the early universe. However, recent simulations also suggest that some globular clusters may be the surviving cores of ancient dwarf galaxies that were stripped of their outer stars by larger galaxies. Either way, they're a fossil remnant hinting at how galaxies evolve.

Globular clusters are not unique to the Milky Way. They are found around many kinds of galaxies, including spirals, giant ellipticals and dwarfs. The Andromeda galaxy, the nearest large spiral galaxy to the Milky Way, is estimated to host about 460 globular clusters, while the giant elliptical galaxy M87 contains roughly 15,000 globular clusters, according to NASA.

Every second of every day, Earth is bombarded by particles from outer space. Some of these particles are obstructed by our planet's atmosphere but can spray down other particles, while others can zoom through the atmosphere and easily pass through anything, including us.

You won't feel these particles darting through you, but it raises a question: How many cosmic particles are actually passing through your body at any moment?

The most common particles that stream through us from outer space are ghostly specks known as neutrinos. "An estimated 100 trillion neutrinos pass through each of us every second," Michael Pravica, a professor of physics at the University of Nevada, Las Vegas, told Live Science.

Neutrinos barely interact with regular matter. Nearly all of them pass through us and the rest of the planet without leaving a trace. "The fact that most of these particles never interact with us demonstrates that there is an underlying reality to our existence, much of which we are not even aware of," Pravica said.

Neutrinos originate from nuclear activity. Nearly all of the neutrinos zipping through us come from the nuclear fusion reactions that power the sun, although some neutrinos originate much farther away, even other galaxies, Lu Lu, an assistant professor of physics at the University of Wisconsin-Madison, told Live Science.

Other extraterrestrial particles that continually strike Earth are cosmic rays — electrically charged, highly energetic particles that travel at nearly the speed of light from all directions, according to the University of Chicago. Although the sun's nuclear reactions produce very-low-energy cosmic rays, the vast majority of cosmic rays come from beyond the solar system. These may be created when faraway stars explode as supernovas, matter falls into supermassive black holes, or galaxies collide, per the University of Chicago.

Cosmic rays are mostly either protons, which are the nuclei of hydrogen atoms, or the atomic nuclei of heavier elements (which contain both protons and neutrons), such as helium or iron. Electrons and positrons (the antimatter counterparts of electrons) also make up a tiny fraction of cosmic rays.

When cosmic rays hit Earth, they are generally blocked by molecules of air high in our planet's atmosphere, Lu said. However, these collisions can generate showers of secondary particles that make it to the ground. These include muons, which are negatively charged subatomic particles that are much like electrons except more than 200 times more massive.

At sea level on Earth, about one muon passes through per 0.15 square inch (1 square centimeter) per minute, Lu said. "For a person, the number ranges from tens to hundreds per second," she noted. "Roughly one or two pass through a hand each second."

Because muons are electrically charged, they can interact with matter they encounter. "Their paths can be made visible in a cloud chamber," a box of vapor in which a trail of mist can be seen when a charged particle streaks through the vapor, Lu said.

In contrast, neutrinos are not electrically charged. They also have almost no mass. These two qualities make it very difficult to detect neutrinos, which is why they're often dubbed "ghost particles."

Detecting cosmic particles

Scientists estimate the number of neutrinos that pass through our bodies by recording "the tiny fraction that happen to collide with matter inside or close to a detector," Lu said. "Everything else follows by working backward from those few."

For instance, the IceCube Neutrino Observatory in Antarctica surrounds 0.24 cubic mile (1 cubic kilometer) of ice with thousands of light sensors. "When a neutrino interacts with an atomic nucleus in the ice, it produces fast-moving charged particles, and those particles emit a faint flash of blue Cherenkov light, which the sensors record," Lu said. "From the pattern and brightness of that light, we can reconstruct the neutrino's energy and direction."

To estimate how many neutrinos pass through Earth based on these recorded interactions, "we account for the size of the detector, how long it operated, its detection efficiency, and the probability that a neutrino of a given energy interacts at all," Lu said. "It is a bit like estimating the number of fish in a river from the few caught in a very coarse net. If you know the size of the net, how long it was in the water, and how easily fish slip through it, you can work backward to the whole river."

When it comes to the neutrinos that IceCube studies, although trillions pass through each of our bodies every second, nearly none of them interact with our atoms. "You would expect no more than roughly one interaction in your body, perhaps a few, over an entire lifetime," Lu said.

These rare interactions would have virtually no effect on us. Given how little energy such an interaction would deposit, such neutrinos "pose no health risk at all," Lu said.

In contrast, the showers of particles resulting from cosmic ray impacts can potentially affect human biology. "At ground level, muons dominate the penetrating charged particles reaching us from cosmic-ray showers," Lu said. "At higher altitudes, and especially during air travel, other secondary particles, particularly neutrons, contribute a significant share of the biologically relevant dose."

Still, any effects from these cosmic-ray showers are generally small. "For an average person, cosmic radiation contributes roughly 0.4 millisieverts per year, about the same as a few chest X-rays spread across the year, out of a total natural background of about 2.4 millisieverts from all sources," Lu said. "The dose varies with altitude, latitude and shielding. At typical ground level, muons and other cosmic-ray particles are not considered a significant health hazard. Life on Earth has been bathed in them from the beginning."

So, every second, there are about 100 trillion neutrinos and tens to hundreds of muons passing through your body per second, and maybe a tiny scattering of neutrons and other cosmic particles or debris from cosmic particles impacting the atmosphere.

These cosmic particles may lead to a variety of discoveries. For instance, scientists have used muon detectors to identify hidden passageways in pyramids. And "high-energy neutrinos allow us to study some of the most violent and otherwise hidden environments in the universe, such as the regions surrounding black holes, exploding stars and other powerful cosmic accelerators," Lu said.

"Because neutrinos interact so weakly, they can escape from dense regions that light may not be able to penetrate," she explained. "They therefore carry information directly from the places where some of nature's most energetic particles are produced."

All in all, "the particles streaming through us are a constant reminder that we are not separate from the universe," Lu said. "We are part of a cosmic story stretching back 13.8 billion years."

See how much you know about black holes with our black hole quiz!

There's a commonly cited idea that water in a drain swirls in opposite directions in the Northern and Southern hemispheres. But is there any truth to it? When you pull the plug from a bathtub, does the water circle one way in New York and the other way in Sydney?

Although the idea is based on a real scientific principle, you probably won't see it play out in a small drain in your house, experts told Live Science.

The Coriolis effect

The idea that water spins in opposite directions in the Northern and Southern hemispheres stems from a phenomenon known as the Coriolis effect. When something, including air or water, moves across Earth as it rotates on its axis, that substance appears to curve because the ground beneath it is rotating at different speeds in different places. Points close to the equator move faster than points near the poles because they have a bigger circle to travel in the same 24 hours.

Over the immense distances covered by weather systems and ocean currents, that small deflection can accumulate and become important. The key words here are "immense distances." The Coriolis effect is weak, so it needs enough time and space to produce a noticeable change. Storms and weather patterns can persist for days and stretch across hundreds of miles. But water in a sink, bathtub or toilet has only seconds to move before disappearing down the drain.

"You always need to think about the right timescales and length scales," Susanne Horn, a professor of numerical and mathematical fluid dynamics at Coventry University in the U.K., told Live Science.

At your bathroom's scale, seemingly trivial details take control. The water may already be rotating slightly because of how it entered the basin, how somebody moved in the bath or how the plug was removed. The sink and drain are unlikely to be perfectly symmetrical, which can also play a part, and the design of a toilet deliberately guides its water. All of these factors are more influential on your basin than the Coriolis effect is. (In other words, that episode of "The Simpsons", which features Bart investigating drainage direction in Australia versus the U.S., got it wrong.)

Consequently, the same sink can drain clockwise on one occasion and counterclockwise on another, depending on the variation of these variables on any given day; the direction depends principally on how the water was introduced and the geometry of the container and drain, according to the Library of Congress.

So, although the Coriolis effect behind the claim is real, the water in a bathroom drain is normally overwhelmed by much stronger influences.

How to see the Coriolis effect in action

To make Earth's rotation ‪—‬ and, thus, the Coriolis effect ‪—‬ matter in a drainage experiment, Horn said, "there are essentially two tricks: let it drain very slowly, or make it much bigger."

Fluid dynamicists describe this using the Rossby number, which compares a flow's inertia with the influence of the planet's rotation. A small Rossby number indicates the Coriolis effect is important; a large one means the flow is moving too quickly or across too short of a distance, for Earth's rotation to have much influence. A typical household drain falls firmly into the latter category. In Horn's words, it "doesn't feel rotation."

Still, there are ways to see the Coriolis effect in action. In a meticulously designed experiment researchers suppressed those larger disturbances to give the Coriolis effect enough time to emerge.

In the 1962 experiment, described in the journal Nature, an MIT researcher used a large, carefully prepared tank that removed residual movements in the water before it drained. The water eventually developed the counterclockwise rotation predicted for the Northern Hemisphere.

Three years later, in another study published in Nature, researchers at the University of Sydney published a Southern Hemisphere counterpart. After taking similarly stringent precautions against outside disturbances, they observed the predicted clockwise rotation. The two experiments demonstrated that Earth's rotation could select the direction of a draining vortex — but only under extremely well-controlled conditions. In other words, the Coriolis effect appears only once you've removed practically every other variable.

That is very different from saying every sink or toilet flows in the same direction according to which hemisphere they're in. In normal plumbing, the drain's shape, the water's starting motion and the way it is released are all far more influential.

"Just ask yourself whether what you're looking at happens slower than Earth's rotation and for long enough, only then does the Coriolis force really start to matter," Horn said.

As wildfires raged through Ontario, Canada in mid-July, millions of people in the Midwest and on the East Coast found themselves under a shroud of yellow skies, darkened by smoke from the infernos. The air quality index in Grand Rapids, Michigan hit 616 on July 16, breaking the previous record for the city of 350; any number over 301 indicates hazardous, emergency conditions.

Smoke events like this are only likely to worsen in the coming decades: Wildfires are one of the most imminent impacts of climate change.

Not only do the flames themselves directly threaten lives, but the smoke can trigger heart attacks, asthma attacks and premature births, as well as worsen heart disease or lung ailments such as chronic obstructive pulmonary disease (COPD). And those effects can spread as insidiously as smoke travels.

A 2025 study found that the record-breaking 2023 Canadian wildfire season may have shortened the lives of 87,000 people exposed to the smoke plumes worldwide. Another 2025 study found that wildfire smoke contributed to 41,380 excess deaths per year in the U.S. between 2011 and 2020 and that the number will rise to 71,420 excess deaths by 2050 if global temperatures rise 5 to 8.3 degrees Fahrenheit (2.8 to 4.6 degrees Celsius) by the end of the century.

In North America, the health impacts of this extra fire are likely to be significant. Wildfire season is getting longer and more intense in the West and Southwest, while regions not historically prone to wildfires will need to deal with the impacts of smoke plumes that can travel thousands of miles.

"Wildfire smoke is the fastest-growing environmental threat [to health] in the U.S.," said Marshall Burke, a professor of global environmental policy at Stanford University who was the senior author of the study predicting the grim rise in excess deaths. "It's just changing so rapidly."

Longer fire season, bigger blazes

Even a rapid drop in greenhouse gas emissions wouldn't fully mitigate the growing risk of wildfires. Because these gases persist in the atmosphere for decades, a more fire-friendly future is already locked in.

"No one foresees changes in the near future, at least, that are going to result in decreases in wildfire," said Mary M. Johnson, a principal research scientist in environmental health at the Harvard T.H. Chan School of Public Health. Wildfires are "predicted to increase in size, intensity and frequency."

Global data suggests that without climate change mitigation, fires will increase in all vegetation types by the end of the 21st century. Even if warming is held to 2.2 F (1.5 C) over pre-industrial temperatures ‪—‬ an increasingly challenging goal to meet ‪—‬ fires outside of tropical latitudes will become more frequent.

In the U.S., the picture is bleak. Between 1984 and 2015, the number of large wildfires in the U.S. West doubled, according to the National Oceanic and Atmospheric Administration (NOAA). The seasonality of fire is also shifting. A February 2026 study published in the journal Geophysical Research Letters found that climate change is nudging fire season in the boreal forests of Alaska and Canada forward as winter snow vanishes earlier, leaving spring vegetation dry and ripe to burn. In the U.S. West, on the other hand, fire season is stretching later because of summer drought.

"It's about dryness," GRL study senior author Hongliang Zhang, an air quality researcher at China's Fudan University, told Live Science.

Climate change warms the atmosphere, and a warmer atmosphere can hold more water. But changes in precipitation patterns can still lead to increased dryness and drought, Zhang said. With climate change weighing the scales toward more intense bouts of rainfall, a particular location could see more precipitation but still experience a simultaneous increase in dry or drought periods, he added.

Zhang and his colleagues found that under a scenario in which temperatures rise by about 7.9 F (4.4 C) by 2100 — a high-emission scenario in which we do little to curb carbon output — fire season would move forward by about a week in Canadian and Alaskan forests, with some of the northernmost regions of Canada and Alaska seeing shifts of up to 23 days. California, with its Mediterranean-like climate, would experience a peak burning shift later in the season. In the Southwest, fire season under this scenario would start a week later but end more than a month later than it does now.

How wildfire smoke is poisoning the air

All of this spells bad news for human health in the U.S. More frequent and intense fires will fuel dramatic increases in air pollution. For instance, a 2020 study suggests that particulate smoke pollution levels will double or triple in the Pacific Northwest and Northern California under unmitigated warming by the end of the century. And even though the West is the U.S. region most prone to fire, wildfire smoke pollution won't stay there. Instead, it will travel across the country, worsening air quality on the East Coast and in the Midwest, Burke and his colleagues found. Depending on the level of warming, smoke emissions will increase 262% to 482% between 2046 and 2055 compared to 2011 to 2020, the researchers found.

Climate change also brings an uptick in severe weather, including winds, Johnson told Live Science. More wind means smoke can travel many thousands of miles. For example, the smoke from the 2023 Canadian wildfires reached Europe and Asia, and that trend is likely to worsen.

"There really isn't any place in the world now where you can say, 'I'm not going to be exposed to smoke,'" she said.

When wildlands burn, they produce PM2.5, a fine particulate matter that is small enough to slip into the bloodstream. Epidemiological studies have linked exposure to PM2.5 to a range of health issues, including dementia, kidney disease and lung cancer. The particles increase oxidative stress on cells in lab dishes, induce cell death, and cause DNA damage that can lead to cancerous mutations, among other impacts.

The damage is evident during big fires. For instance, exposure to wildfire smoke raises the risk of heart attack, stroke and other cardiovascular emergencies, according to a study of California emergency department visits during the 2015 wildfire season. Cumulative exposure over time, however, is how wildfire smoke causes the most deaths. Between 2006 and 2020, PM2.5 from wildfire smoke exposure was responsible for an average of 24,100 deaths per year in the United States, a study published in the journal Science Advances in February found. Smoke exposure worsened the death rate for every health condition studied, with neurological disease deaths rising most significantly.

Wildfire smoke may also fuel premature births. Just a week of wildfire smoke exposure raised the risk of preterm birth by 3.4%, a 2022 study found — and in a world where smoke exposure could span weeks, that could translate to a significant uptick in the rate of premature birth. Other studies tell a similar story: a 2024 study found risk of premature birth rises with every incremental increase in exposure to PM2.5 from wildfires during pregnancy. And a 2025 study found that preterm birth risk increased in the U.S. West with smoke exposure, regardless of whether that exposure was measured by high-smoke days, exposure to 4-day waves of smoke, or by the concentration of particulate matter in the air.

Wildfire smoke may also affect cognition: A 2022 study found that cumulative exposure to wildfire smoke over the school year was linked to slightly lower test scores for elementary and middle schoolers. And research using data from cognitive brain-training apps has also shown that performance on a cognitive task declines on high smoke days in adults. Over the long term, PM2.5 exposure from wildfires is linked to dementia risk.

Toxic cocktail

Researchers are still working to understand why wildfire smoke is so dangerous to the body. Smoke can contain a toxic stew of ingredients, especially when homes and buildings burn. Air testing after the 2025 Palisades fire in Los Angeles found high levels of silver and chromium-6 nanoparticles, the latter of which are carcinogenic.

Johnson and her team have found that smoke exposure leads to epigenetic changes associated with the immune system.‪‬ In other words, the person's DNA doesn't change, but the way it's translated into building proteins and cells in the immune system shifts. And epigenetic shifts can be passed along to the next generation. One shift is a decline in regulatory T cells, immune cells that help the body tolerate itself and harmless allergens. The immune changes probably play a role in why wildfire smoke exacerbates chronic diseases, Johnson said.

More smoke days can also affect health indirectly, by keeping people from going outdoors. In California, the heaviest smoke days actually have fewer emergency department visits overall, Burke said. On the smokiest days, when the air is noticeably hazy and may even smell like a campfire, emergency department visits for asthma-related reasons rise, but visits related to injuries or car accidents decline even more, probably because everyone is staying home. That may sound like a net benefit, but if forced quarantines happen repeatedly, they can worsen physical and mental health over time, making people more sedentary or less able to socialize.

"It's keeping people from doing things they would otherwise love to do," Burke said.

On the flip side, emergency department visits rise on days when the Air Quality Index indicates a moderate risk or a risk to sensitive groups.On these days, the air may not seem noticeably bad, and people may go out without realizing the amount of pollution they are inhaling until they start to feel ill.

"That's really consistent with this broader air pollution literature that, especially recently, has shown there is no safe exposure level to air pollution," Burke said.

With an increasingly wildfire-friendly climate in its future, Americans will be less healthy. There are ways to reduce the impact, however. Burke and his team have found that controlled burns put off less pollution than wildfires, while reducing the fuel load that turns wildland fires into smoke-churning infernos. An investment in managing fuels could ultimately be an investment in improving the country's health.

"It is within our power to correct that problem," Burke said.

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

The patient: A 41-year old man in Iran

The symptoms: The man visited an outpatient clinic after a week of experiencing extreme discomfort during urination and pain above his pubic bone. His urine stream was weak, and he was unable to empty his bladder.

What happened next: The patient told the doctors that about a month earlier, he had begun to develop incontinence. He self-treated for two weeks by inserting superglue into his urethra.

At first, the superglue seemed to help. But after four days, he began to produce less and less urine and urination became painful. By the time of his clinic visit — two weeks after he stopped applying the superglue — he was barely able to urinate at all and was in constant pain, his doctors wrote in a report of the case.

The diagnosis: During a physical examination, the doctors noted that the man's penis was erect and that they felt a solid foreign body in the penile urethra. They also observed "brittle fragments of superglue" on the opening at the tip of his penis, they wrote in the report.

The doctors attempted to perform a cystoscopy, a procedure in which a tube fitted with a lens enables doctors to look inside the urethra. But the obstruction prevented them from inserting the tube far enough to see anything, and they decided to perform emergency surgery to remove the mass of hardened glue.

The treatment: Surgeons made an 0.8-inch (2 centimeters) incision in the glans, the bulb at the end of the penis. For 15 minutes, they bathed the urethra with 0.8 gallons (3 liters) of saline solution to saturate the glue plug and thus separate it from the walls of the urethra ‪—‬ a feat they eventually accomplished through "certain maneuvers," they wrote.

Finally, the glue broke loose. The doctors extracted a rod-shaped solid glue block measuring nearly 4 inches (10 cm) long.

After the patient recovered from surgery, his urination and urine analysis were normal. He was discharged five days later with a catheter that remained in place for 10 days, and he received prescriptions for antibiotics to prevent infection. At a follow-up visit in the sixth week after surgery, his urination was normal and he had no further complications.

The doctors did not identify the cause of the patient's prior incontinence.

What makes the case unique: Application of superglue in body cavities typically occurs in the ear or nose, according to past case reports. Usually, the glue can be dissolved with solvents, such as acetone. However, three other case reports in the medical literature describe patients intentionally inserting superglue into their urethras, and all of those cases required removal with endoscopy or surgery, the doctors in Iran reported.

Urethra tissue is very delicate, and inserting anything into this sensitive tube risks damaging it, which can lead to serious infection. The insertion of foreign bodies into the urethra can also be painful, making the practice "relatively rare," the report's authors wrote.

If a person chooses to do this, they added, it may be to satisfy curiosity or as a result of intoxication or mental illness, but the most common motivation is sexual stimulation. Despite the risks, numerous case reports describe people pursuing pleasure by introducing a wide range of diverse objects into their urethras, including magnets, pencils, earphones, a dining fork, a thermometer, the ink chamber from a ballpoint pen, the metal tip of a screwdriver, a USB cable, a tree branch and three AAA batteries.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

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

Can you guess the diagnosis in these strange medical cases? Find out with our diagnostic dilemma quiz!

This eye-catching astronaut snap shows a rare phenomenon known as a "sunglint," which transformed a Pacific island into a pseudo-magnifying glass with a shining silver lens.

The uniquely shaped landmass is Rennell Island (also known as Mugaba or Mu Nggava), one of the southernmost of the Solomon Islands — an archipelago nation of nearly 1,000 islands, atolls and reefs that lies between Australia, Papua New Guinea and Fiji. It is up to 50 miles (80 kilometers) long and 8 miles (13 km) across at its widest point.

At the southeastern end of the island (right side of this photo) lies Lake Tegano (also known as Lake Te Nggano), a roughly 60-square-mile (155 square kilometers) body of brackish water, which is surrounded by a jagged ring of coral topped with dense forest. It is the largest lake on any Pacific island, according to Britannica.

In this photo, sunlight reflects off the surface of both the Pacific Ocean and Lake Tegano directly into the astronaut's camera, making the water appear metallic. This sunglint effect is the strongest on the lake's left side and a horseshoe-shaped bay on the island's bottom edge, because these areas are most sheltered from the wind and therefore have the stillest and most reflective surfaces, according to NASA's Earth Observatory.

Shadows from clouds are peppered across the sea's silver surface, adding an element of depth to the scene.

Sunglints are useful to scientists because they can help reveal hidden oceanographic features, such as subsurface currents, oil slicks and internal waves, which look like marks on a mirror when this phenomenon is ongoing. Sunglints can also occur on land when sunlight reflects off rivers or illuminates large lakes.

However, the reflected sunlight can obscure parts of aerial images, making them a nuisance in certain tasks, such as hurricane tracking. As a result, sunglints are digitally removed from most satellite images, according to the National Oceanic and Atmospheric Administration (NOAA).

Rennell Island is an atoll, meaning it is built on top of the remains of an ancient coral reef, most likely left behind when another island sank into the sea long ago. Its highest point sits around 500 feet (150 meters) above the ocean surface, making it the tallest atoll in the world, according to Britannica.

The landmass is surrounded by a fringing coral reef, which can usually be seen in aerial photos as a light-blue or turquoise band around the atoll's edge. However, because of the sunglint, the reefs have disappeared from view in this image. Similarly, Lake Tegano has several small islands that can't be seen here due to the reflected sunlight.

The region surrounding Lake Tegano is a biodiversity hotspot and has been listed as a UNESCO World Heritage Site. This area, dubbed East Rennell, is home to more than 20 endemic bird species, as well as the Crocker's sea snake (Laticauda crockeri), which is vulnerable to extinction, according to the Earth Observatory.

See more Earth from space

This massive limestone carving depicts a Maya queen known as Lady K'abel (meaning Water Lily Hand) and Na Kan Ajaw (meaning Divine Woman of the Snake Polity). The stela, or carved stone slab, was likely erected in A.D. 692 to mark the end of a k'atun, a 20-year period in the Maya calendar.

The stela is in the collection of the Cleveland Museum of Art (CMA). It has been reconstructed from more than 40 fragments of carved limestone but is only the front part of the original freestanding monument. The enormous carving is roughly 9 feet (2.74 meters) tall and weighs about 2,500 pounds (1,134 kilograms). It was found in a provincial Maya town called El Perú-Waka' in the Petén region of northern Guatemala.

In Petén, this carved portrait of Lady K'abel stood next to a similar one of her husband, K'inich Bahlam II, a man of lower rank. As a member of the powerful Kaanul or Snake dynasty, Lady K'abel ruled El Perú-Waka' as the military governor, according to the CMA. The stela also describes her as Ix Kaloomte', meaning Lady Supreme Warlord, and experts think Lady K'abel may have led an army from the city of Calakmul against the city of Tikal.

On the stela, Lady K'abel is "smothered in finery," Susan E. Bergh, then curator of Pre-Columbian and Native North American art at the CMA, wrote in 2014, which "allies her with a Maya supernatural being, either the maize god or the moon goddess." Her headdress is a fan of green quetzal (Pharomachrus mocinno) feathers, and she wears a netted garment and necklace, both made of jade beads. The net dress is belted with the head of a fish-like creature, and Lady K'abel carries a scepter and a circular shield, alluding to her role as Lady Supreme Warlord. In the lower-left corner is a person with dwarfism, likely an attendant or courtier.

The stela was created to celebrate 20 years of Lady K'abel's rule. Portraying her as the maize god conveys themes of creation and renewal, archaeologist Phil Wanyerka wrote in a 1996 study. "By wearing the attire of a god, a mortal being becomes divine, and here a woman is transfigured into the maize god to summon the associated powers of renewal and rebirth for the passage of the old k'atun and the inauguration of the new," Wanyerka wrote.

Although Lady K'abel's stela was acquired in 1967, her tomb was not discovered until 2012, when archaeologists excavating at El Perú-Waka' stumbled across it when digging at the bottom of a previously unknown staircase near where the stela was found.

According to archaeologist Olivia Navarro-Farr, who led the excavation, the royal tomb was full of artifacts made from jade, obsidian and shells, including a bivalve shell placed on the skeleton's pelvis. The shell exactly matches one depicted on Lady K'abel's pelvis on the stela. In the tomb, the archaeologists also found a small alabaster carving with hieroglyphs that named Lady K'abel as its owner, almost certainly linking the occupant of the tomb with the imposing limestone stela that was discovered outside.

"It's not rare to find royal tombs," Navarro-Farr said. "But it is rare to have the perfect confluence of evidence that leads one to be able to make that kind of historical identification."

Editor's Note: This story was updated on Aug. 25 at 9:35 EDT to correct the headline. The stela is 1 ton, not 2 tons.

For more stunning archaeological discoveries, check out our Astonishing Artifacts archives.

Can you put together last week's Astonishing Artifact?

In a scene reminiscent of Vincent van Gogh's "The Starry Night," scientists have captured swirling nebulae, dark dust lanes and sparkling star clusters in remarkable detail.

This spectacular new image from the Dark Energy Camera (DECam) on the National Science Foundation's Victor M. Blanco 4-meter Telescope in Chile shows the Corona Australis Molecular Cloud, one of the closest active star-forming regions to our solar system. It's a place where temperatures fall to around minus 440 degrees Fahrenheit (minus 260 degrees Celsius), allowing dense pockets of gas and dust to collapse and form new stars.

The portrait also combines star-forming regions with an ancient globular cluster far beyond them, all within a single field of view. The 570-megapixel DECam's 74 detectors and 3-foot-wide (1 meter) lens make it one of the world's most powerful wide-field astronomical instruments.

On the left side of the image is the glowing nebula NGC 6729, nestled within the molecular cloud. The blue is a reflection nebula, which is caused by dust reflecting starlight, while the orange shows an emission nebula, which forms when ultraviolet radiation from a young star ionizes gas with its youthful radiation. At the heart of NGC 6729 is R Coronae Australis, a binary star system whose stars complete an orbit of each other every 43 to 47 years.

Glittering like a firework on the upper right is NGC 6723, a globular cluster approximately 29,000 light-years from Earth. Also called the Chandelier Cluster, it contains hundreds of thousands of stars that formed billions of years ago, with some almost as old as the universe itself. However, astronomers suspect that there are several populations of similarly aged stars within the cluster, indicating a complex evolutionary history.NGC 6729 and NGC 6723 are favorite targets for astronomers and astrophotographers because of their relatively close proximity to Earth. However, because they're found below the constellation Sagittarius, they're best seen from the Southern Hemisphere. If you’ve got the right vantage point, a good backyard telescope will help you see this chaotic cradle of star formation.

Every person you know has a name, and you've likely given one to your pets, too. But are names a uniquely human feature, or do other animals also call each other by name?

Research suggests that some mammals and birds use vocal labels for other individuals, but not all scientists agree on how to interpret the evidence.

In the 1960s, scientists discovered that young bottlenose dolphins (Tursiops) create individually distinctive whistles, called signature whistles. Researchers in the years since have conducted experiments in which they played the whistles through an underwater speaker and observed how the dolphins responded. Dolphins copy the signature whistles of other dolphins to initiate contact, similarly to how we use names, and can recognize other individual dolphins based on the frequency and "shape" of the whistle, regardless of the voice of the dolphin whistling.

Dolphins do seem to assign these whistles to other individuals and to match the whistles to others in a more symbolic way, Kelly Jaakkola, a cognitive psychologist at the Dolphin Research Center in Florida, told Live Science. Research shows that dolphins whistle to identify each other within complex social systems and while cooperating on tasks.

Through playback experiments, researchers also found that wild African elephants (Loxodonta) address one another with specific vocalizations ‪—‬ low rumbling sounds that are unique to each individual. The team published their findings in 2024 in the journal Nature Ecology & Evolution.

"They sound a little bit like a giant cat purring," Michael Pardo, a behavioral ecologist at Colorado State University and first author of the study, told Live Science. Elephants tended to approach speakers more quickly, and vocalize more in response, when their "name" was played.

Playback experiments have also suggested that spectacled parrotlets (Forpus conspicillatus), small parrots native to parts of South and Central America, use vocal labels for other parrotlets.

Studies of birds in captivity can shed light on their capacity to learn vocal labels. In a survey of parrot owners, about half of the 800 birds used vocal labels for individual people and animals that they had learned from the people around them.

"Parrots certainly pick up a lot of things from humans — they don't necessarily know what it means in a human linguistic context, but they know when to say it," Lauryn Benedict, a biologist at the University of Northern Colorado and first author of the study that surveyed parrot owners, told Live Science.

One survey participant said their parrot corrects people when called by the wrong name; others said their parrots correctly used the names of all humans and dogs in the household. However, these behaviors look different from those in wild parrots, and further research is needed to dig into whether spectacled parrotlets understand the concept of names and actually give names to their fellow birds.

How do you define a name?

Claiming an animal noise is a name, as humans define it –– a specific, symbolic vocal label attached to an individual –– is complicated.

One study in marmosets suggests that they use vocal labels. Using playback experiments, the researchers discovered that the marmosets directed certain vocalizations at specific individuals and that they learned these vocalizations from family members. However, in a published response to that study, Jaakkola argued that the calls may not be name-like, since they were correctly identified only 16% to 61% of the time. Jaakkola proposed that the marmosets may have been imitating each other's vocalizations.

However, she noted that we can't generalize any one interpretation to all species.

"The elephant case is very different from the marmoset case and the spectacled parrotlet case," Jaakkola said. "It can be really hard to have a cohesive discussion [across species] ... to all talk about the same thing."

In a July 2026 paper, Jaakkola and colleagues proposed three minimum criteria to apply across species: individual reference, meaning the call is designated for one particular individual; symbolic representation, meaning the name stands for a specific individual in the user's mind; and shared meaning, where at least two individuals associate the name with that individual.

When applying these criteria to the current evidence, Jaakkola said bottlenose dolphins show the strongest evidence for the use of animal names. Elephants, parrots and marmosets, on the other hand, require more research about symbolic representation to prove naming behavior.

"It is a big claim when you call something a name," Jaakkola said. "Our goal here was to create a unified framework … to start looking at this question more systematically."

Why are names useful?

Species that may use name-like calls have a couple traits in common: They can learn new sounds, and they're extremely social. Names might be useful in animal groups in which the community breaks into smaller subgroups and individuals are often out of their companions' sight, Pardo said.

The behavior seems present in very different lineages, so it may have evolved separately multiple times, which can tell scientists about the evolution of language among complex social pressures, Pardo said.

By studying whether animals use names, scientists can learn about the cognitive abilities necessary for abstract mental representation of other individuals. "For humans, names are such a part of our individuality and our sense of self, that if animals have names and respond to those names, that suggests they could have a sense of self … and of other individuals and their individuality," Benedict said.

Jaakkola clarified that although it's difficult to demonstrate naming behavior in nature, she's not ruling out that nonhuman animals have name-like calls. Rather, the evidence is not yet sufficient to say they do, she said.

Pardo agrees that more evidence would confirm these behaviors in more species, but he suspects a lot of animals may be calling each other by name.

A lot of other animals, such as baboons, giraffes, and crows, have communities that break into smaller groups. While there isn't evidence for names in species like these, and this social structure would need to be paired with vocal learning abilities, "I think it might be more common than we currently realize," Pardo said.

What do you know about the animal kingdom? Test your knowledge with our animal quiz!

In the early hours of July 16, 1945, in a remote part of the New Mexico desert, a group of scientists, engineers and military personnel attended an event that would define the course of history and change a war that had ravaged much of the world for years. Moments after a giant fireball rose high into the sky, a huge shock wave thundered toward the onlooking crowd. The Trinity nuclear test had been a success.

The story of the Manhattan Project is well known. But one area that may be overlooked is the human effort involved in bringing the mission to life. In her new book "Trinity: An Illustrated History of the World’s First Atomic Test" (The University of Chicago Press, 2026), author Emily Seyl, a science writer and editor at the Los Alamos National Laboratory's National Security Research Center, uses never-before-seen photography from the laboratory’s legacy collections to highlight the physical and mental effort that went into the project.

In this excerpt, Seyl examines one of the key elements of any scientific experiment — how to successfully measure the results. She looks at how experiments were decided upon and the ways in which success would be measured, beyond the visual spectacle of a successful detonation of "the Gadget."

T‌he most rudimentary measure of success would, of course, be the eye test: Did the Gadget produce a nuclear explosion? Beyond the answer to this simple question, however, the detonation was also a monumental and complicated science experiment — one that naturally gave rise to as many smaller experiments as could be squeezed, sometimes impractically, into the test plans.

Alongside a crowd of Trinity contributors, a robust collection of electronic and mechanical observers was stationed carefully throughout the desert to bear witness to the shot. Although deceptively rugged and nondescript, these devices were highly sophisticated, often employing first-of-their-kind technologies — invented and built by some of the world's preeminent researchers to study a first-of-its-kind event.

After two years of leapfrogging basic nuclear studies in their rush to produce a workable device, the pioneering scientists now "yielded to temptation and conceived experiment after experiment" in anticipation of the Trinity test — much to Kenneth Bainbridge's [director of the Manhattan Project's Trinity nuclear test] alarm. In December of 1944, with base camp still under construction at the test site, a selection committee, headed by Bainbridge, had been established to evaluate what was quickly becoming a deluge of ideas.

The committee implemented a detailed submission process, requiring scientists to scrupulously outline the personnel and material needs associated with carrying out each idea. Proposed subtests were triaged into three categories: essential experiments, which were fully greenlit no matter the required effort or resources; desirable experiments, which were approved only if they did not interfere with work on the Gadget itself; and unnecessary (i.e., nonessential) experiments, of which only the simplest were allowed.

Completing the Gadget remained the top priority. But while most of the lab continued to work feverishly on readying the test device, a significant battery of physicists, photographers, chemists, engineers, and other specialists began coming and going between Los Alamos and the Trinity site in March, as Jumbo [a containment vessel for use in case the nuclear explosion failed] faded into the background. With confidence increasing and a clear emphasis on learning everything possible about the performance of the test device, they were consumed from dawn to dusk with readying cameras and other diagnostic instrumentation to track the effects of the blast from detonation to dissipation.

The greatest unknown was how much energy would be released by the weapon. This value — also known as the yield — would depend on how much of the plutonium fuel underwent fission. The aim was to get as much energy from the explosion as possible.To quantify whatever success or failure awaited, scientists made plans to observe three manifestations of that energy: the amount of radiation emitted from the core (including neutrons, gamma rays, and fission fragments); the pressures and speeds of the air and ground shock waves; and the size and temperature of the fireball, which would indicate the amount of energy released as heat.

With the right combination of approaches and protections, they hoped to record in several ways all effects of the explosion. If the experiments were to have any chance of capturing the various expected phenomena, however, they had to be set up close enough to absorb and record the effects while simultaneously far enough away to withstand them. Difficult decisions about siting and fortification were made harder by the fact that only rough and frequently changing estimates of the Gadget's capacity for destruction were available to serve as guideposts.

Nevertheless, scientists brought the rigor of the laboratory to the desert in dozens of clever ways. Some of the myriad devices relied on communication lines to quickly carry data back to recording instruments in bunkers. Others were programmed to send up visual signals that would be filmed by timestamped cameras placed at safer distances.

Still others were purely mechanical, installed dangerously close to the blast but made of resilient materials or buried underground, the plan being to recover them in the aftermath to harvest data. Not knowing which approaches to the balancing act would turn out to be successful, they relied on overlap and redundancy to account for failure.

Although the cameras and instruments ultimately, and not unexpectedly, varied in their performance, the experimental program altogether would succeed in committing to history a comprehensive visual record and a trove of data, built upon the talents and toils of many.

We all know that a dropped or shaken soda can comes with the risk of a fizzy eruption. People use different techniques to prevent these bubbly blasts, including tapping the top of the can. This advice has been passed around for years, but does it actually work?

The answer lies in the physics of what's happening inside the can.

Building the bubbles

To make a carbonated drink, carbon dioxide is injected into the liquid — such as soda, beer or Champagne — at a high pressure and cold temperature.

"[Bubbles] are formed as a result of what is called supersaturation of carbon dioxide," Roberto Zenit, a professor of engineering at Brown University who studies fluid mechanics, told Live Science.

Supersaturation is an unstable state where a liquid or gas can hold more dissolved materials than normal conditions allow. Thanks to its instability, there are some actions, like shaking a can, that can encourage more bubble production.

"The mechanical action (tapping or shaking) generates violent pressure waves inside the liquid; these waves rebound at the walls, creating low-pressure zones where tiny bubbles form," Javier Rodríguez Rodríguez, an associate professor of fluid mechanics at Carlos III University of Madrid, told Live Science in an email. "If given enough time (minutes to tens of minutes, depending on the drink and container), these bubbles dissolve again and the can 'forgets' that it has been perturbed."

However, if the soda can is open while the bubbles are suspended in the liquid, the sudden pressure drop from opening the can encourages more bubble production, resulting in more spillover, Rodríguez Rodríguez said.

In some rare cases, like spraying Champagne after a NASCAR victory, creating a geyser of foam is exactly the goal, which the drivers accomplish by vigorously shaking the bottles beforehand.

Does tapping actually work?

Unlike NASCAR drivers, most people are looking to save their drink‬, so they may try tapping the top of the can.

The idea behind this strategy has some merit. According to Zenit, carbon dioxide bubbles can expand out of tiny imperfections called nucleation sites, which can include dust particles or rough spots on the can.

"The reason why you tap is basically to remove possible bubbles or dust particles within the soda can," Zenit said. If you remove those, you can reduce the rate of bubble formation, he added.

In theory, a few gentle taps could knock loose some bubbles clinging to the walls of the can, allowing them to float into the pocket of air above the soft drink before it's opened. With fewer nucleation sites left in the liquid, there would be fewer places for bubbles to rapidly grow once the can was opened and the pressure dropped.

But that explanation comes with an important caveat: While gentle tapping might dislodge a handful of bubbles, tapping too hard, or tapping repeatedly, could create more bubbles, Rodríguez Rodríguez said. The same principle applies to carbonated drinks in glass or plastic bottles, as tapping down on a beer bottle can encourage foam to fizz over.

Those competing effects make it difficult to determine whether tapping actually helps, and some experiments suggest that overall, it probably doesn't.

In one preprint study from 2019, researchers tested 1,031 cans of beer by dividing them into four groups: shaken and tapped, shaken and untapped, unshaken and tapped, and unshaken and untapped. The tapped cans were flicked three times on the side with a finger before being opened. The researchers found no statistically significant difference in the amount of beer lost between the tapped and untapped cans, regardless of whether they had been shaken. They concluded that tapping "does not prevent beer loss" and that the practice isn't supported by their observations.

That doesn't necessarily settle the question for soda, but it hints that tapping is not an effective method.

"Beer and soda differ in composition and foaming behavior, but the study provides relevant experimental evidence that tapping is not a demonstrated solution," Kit Yam, a food scientist at Rutgers University, told Live Science in an email.

How do you prevent a soda can from fizzing?

If tapping isn't the answer, time probably is. Letting a shaken can sit upright for several minutes gives the bubbles time to dissolve or rise into the air pocket at the top of the can. Keeping the drink cold can also help, because carbon dioxide stays dissolved more easily at lower temperatures.

"Put the can you accidentally dropped or hit in the fridge for half an hour and open another one in the meantime!" Rodríguez Rodríguez said.

If you don't have another can or you don't want to wait, Rodríguez Rodríguez suggested another option: opening the can slowly.

"In this way, the gas can escape, but I only leave a tiny slit for foam to fizz out," he explained. "Then, when you hear the gas is no longer escaping, you can safely open the can completely."

You can use the same process to reduce the amount of foam that spills over when you pour a carbonated drink into a glass.

"If you pour it slowly," Zenit said, "then you reduce this agitation."

In 2010, researchers at Purdue University and the University of New South Wales began an investigation into a macabre question: What's the upper temperature limit at which humans can survive? The answer, according to their calculations, was 95 degrees Fahrenheit (35 degrees Celsius) at 100% humidity — a "wet bulb" temperature that sets an absolute "unsurvivable" threshold for the human body.

Beyond this temperature, a cascade of irreversible physiological processes begins, sending organs into shock, causing blood to clot and ending in inevitable death.

As the climate warms and heat waves multiply, more places across the globe are creeping towards this threshold, with climate models projecting the first 35 C wet bulb temperatures by the middle of the century.

But conditions don't have to be this hot or humid to be unlivable in a practical sense for wide swaths of the population. The threshold is lower for those who are older, for women, and those with certain medical conditions. Any kind of physical activity also raises the risk of heat stress.

In some parts of Asia, South America and Australia, the hottest days are already "unlivable," meaning a healthy adult sitting in the shade in a slight breeze could be at risk from heat illness, a recent study found.

In North America, the hottest days in parts of the Southwest and Southeast pose that same risk, the study found. And more heat is coming: Under projected warming, the country will see tens of thousands more heat-related deaths by 2100.

Nearly 20,000 people could die from extreme heat each year by the middle of the century in the United States. The U.S. and Mexico could see an additional 9,000 suicides each year.

Heat can kill directly, via heat stroke, but it can also worsen underlying cardiovascular health, turning chronic, manageable heart conditions deadly. Heat waves often occur hand in hand with droughts or other extreme weather and may lead to food and water price hikes or shortages, said Marina Romanello, a senior research fellow at the University College London Institute for Global Health who tracks how the climate affects health. In that sense, climate change acts as a stress multiplier.

And heat could erode health in other, subtler ways, making nights more sleepless and our cognition a bit cloudier.

"No individual metric really does justice to the overall risk to health and well-being of these multiple stressors being exacerbated all at once and compounding each other," she told Live Science.

Heat wave deaths

Heat kills most immediately through heat stroke, which occurs when the core body temperature soars over 104 F (40 C) and doesn't cool down. Dangerous heat waves — and resulting deaths — have already increased over the past several decades. In 2023, heat was described as the main cause or a major underlying cause of death on 2,325 U.S. death certificates, an increase from 1,069 in 1999, research shows. When adjusted for age of the population, that represented a 63% rise in heat-related deaths.

But scientists think heat already contributes to many more deaths than that, because heat isn't always listed as a contributor to death on official records, even if it may have played a role in exacerbating an underlying health condition.

Heat is particularly hard on people with cardiovascular issues, with the risk of a heart attack more than doubling on extreme heat days. The risk of stroke, too, nearly doubles on the hottest days. Some early evidence hints that heat's impact on the immune system may play a role in these cardiac cases. Deaths related to extreme heat days for all reasons are projected to more than double by the mid-century in the U.S., leading to up to nearly 20,000 deaths if temperatures warm 8.1 degrees F (4.5 degrees C).

And rates of hyponatremia, or low sodium levels — which can cause seizures and coma — are also projected to increase as climate change worsens.

Most at risk are older adults, kids and teens, and people who work outside. The heart pumps less efficiently as people age, so older people struggle to pump blood to the skin to cool down. Children produce more heat than adults, given differing fat makeup and a lower skin surface area, and sweat less, making them more prone to developing heat stroke. Outdoor workers often have to exert themselves on hot days and may struggle to hydrate enough to compensate for extreme heat.

People with certain medical conditions are also at high risk. Diabetes can impair sweating and the dilation of the blood vessels that helps cool the body in hot temperatures, making people with diabetes more susceptible to heat stroke. Some medications, including diuretics often taken by people with heart disease, beta blockers for people with heart conditions, and selective Serotonin Reuptake Inhibitors (SSRIs) taken for mood disorders, also increase the risk of heat-related illness because their side effects make it harder for the body to cool itself.

Mental illness itself is also a risk factor. Higher temperatures have been linked to an increase in suicides, with 0.7% more instances of suicides in the U.S. per for every 1.8 F (1 degree C) increase in monthly average temperature. Were temperatures to rise more than 5 degrees C (9 degrees F), that rise could translate to between 9,000 and 40,000 additional suicides in the U.S. and Mexico by 2050, the researchers wrote ‪—‬ similar to the increase in the suicide rate expected in a serious economic recession. (Fortunately, that temperature rise is now considered unlikely due to the world moving away from coal as an energy source.)

It's not clear exactly why hotter days fuel more suicide, but one possibility is that feeling hot and uncomfortable can increase the impulsivity that may underlie the behavior.

And impulsivity rises in people who struggle to stay comfortably cool in their homes, Kim Meidenbauer, a neuroscientist at Washington State University who studies the effect of heat on emotion and behavior, has found.

The effects may be hardest on those who have preexisting mental health conditions, ranging from schizophrenia to anxiety: Mental-health-related emergency department visits have been shown to rise with the temperature.

Perhaps the most universal way heat may compromise health in the U.S. is through sleep. Heat reduces both sleep quality and sleep quantity. For every degree-Celsius increase in nighttime temperature, there is a loss of 3 good nights of sleep per month per 100 people, according to one large-scale sleep-tracking study.

Those sleep disruptions may be the major reason heat has a corrosive effect on mood and mental health, even for those without existing mental health conditions, Meidenbauer noted.

"We see worsened emotional state," she told Live Science. "We see increases in impulsivity." And underslept people struggle to stay on an even keel, perhaps explaining both E.R. visits and a heightened risk of suicide.

"Emotion regulation is a lot harder if you've had poor sleep quality," Meidenbauer told Live Science.

Daily health in a hotter world

Heat affects the mind in other ways, too. People have trouble thinking clearly once temperatures reach 89.6 F (32 C), a study that administered math and verbal reasoning tests to 50,000 people in China found.

The number of days in the U.S. with heat indices over 100 F (37.8 C) is expected to double as soon as a decade from now, while the number of days with heat indices over 105 F (40 C) is expected to triple. The heat index is a measure of what the temperature feels when taking into account air temperature and relative humidity. The more humid the air, the harder it is for the body to cool off by sweating.

Nearly nine in 10 U.S. households have air conditioning, but that doesn't mean Americans are immune to heat waves. The 2024 study in China found that even short-term exposure to extreme heat — on the order of an hour in a couple of days — can cause small declines in math and verbal test scores, indicating some degree of mental sluggishness in hot weather.

Hotter days may drive people indoors, potentially worsening physical and mental health. Exercising outdoors may provide a mental health boost above and beyond exercising indoors. The data is limited by research designs that don't always follow rigorous methods, but losing outdoor exercise opportunities could mean a slide in physical fitness even if people switch to indoor workouts. For example, cancer survivors randomly assigned to indoor and outdoor exercise worked harder when exercising outside, according to one 2020 study. Likewise, teen boys with obesity prescribed playful exercise outside lost more weight and saw greater increases in a molecule that regulates appetite and wakefulness than those who were assigned to use a treadmill indoors, a 2019 study found. People also reported more satisfaction with outdoor exercise versus indoor exercise, which might influence their willingness to keep working out.

Hot days could also curtail kids' sports, which are often played outdoors. In Japan, summer outdoor youth sports in much of the country might need to be restricted for one to four months a year, even under lower-warming scenarios; similar issues could crop up in much of the U.S., which sits at approximately the same latitude as Japan.

Overall, studies find a U-shaped relationship between obesity and temperature, with higher body mass index (BMI) in the coldest and hottest places. One study in Australia found that regular exposure to temperatures above 86 degrees F (30 degrees C) was associated with increases in BMI and obesity.

Adapting to extreme heat

People do adapt to warmer temperatures over weeks or months through physiological changes, as their sweat glands become more efficient and their water retention increases. The cognition study conducted in China found that people who lived in climates that were warmer on average were more resistant to declining test scores in the face of warmer temperatures, perhaps indicating that these physiological changes have practical impacts.

However, extreme heat — and short-term spikes — outpace the human body's ability to adjust, as the increases in heat-related deaths already measured between 1999 and 2023 attest. Likewise, kids are already suffering, especially those in the South where temperatures are highest. A study of two major hospitals in Texas found a 170% increase in pediatric emergency department visits for heat-releated illness between 2012 and 2023.

What works to reduce the impacts of extreme heat is an open question, said Marshall Burke, a professor of global environmental policy at Stanford University. Cities often open cooling centers during heat waves, which may save lives, but whether they do enough hasn't been well studied, he told Live Science.

To try to answer that question, Burke and his colleagues have put together a website, the Environmental Hazard Adaptation Atlas, to pull together data on temperature, heat-related illness and death, and what adaptations might help.

"We need good case studies of what things have worked," he said. "We need good systematic evidence."

The patient: A 65-year-old woman in Qatar

The symptoms: The woman had been dealing with unexplained chest pain for several months, although earlier tests of her heart health had come back normal. She had stopped attending follow-up appointments regarding the chest pain.

But then, she experienced three days of chest pain and shortness of breath that got worse with activity. The symptoms, which began shortly after she attended her daughter’s wedding, initially brought her to a clinic, according to a report of the case.

An electrocardiogram (ECG or EKG) showed changes in her heart's electrical activity. This is a sign doctors look for when diagnosing a heart attack, because during the event, blood flow to the heart is impaired and that can injure or kill heart-muscle cells. So, the patient was rushed to a hospital emergency department.

What happened next: By the time the patient reached the emergency room, her chest pain had eased, but a repeat ECG showed different electrical abnormalities from the local clinic.

Blood tests showed an elevated level of troponin, a protein that leaks into blood when heart muscle is damaged. An ultrasound of her heart showed that its main pumping chamber, the left ventricle, wasn't squeezing properly; its pumping strength, known as ejection fraction, had dropped from 58% five months earlier to just 35%. (The healthy range is 50% to 70%.) The left ventricle had also ballooned out of shape at the tip.

Doctors performed an angiogram, a test that uses a thin tube and dye to check for blocked arteries, and found that her arteries were clear.

An X-ray of her heart confirmed the same ballooning shape that was seen on the ultrasound, and an MRI ruled out permanent damage from a silent heart attack or scarring of the tissue.

The diagnosis: Doctors diagnosed the patient with takotsubo cardiomyopathy, also known as stress cardiomyopathy or "broken heart syndrome." The condition temporarily weakens the heart muscle and causes it to balloon, producing symptoms that closely resemble a heart attack.

The condition is thought to be triggered by a sudden surge of stress hormones, such as adrenaline (also called epinephrine), that temporarily stun the heart. The diagnosis was confirmed using the Mayo Clinic's diagnostic criteria, which require ruling out other potential causes, such as heart inflammation (myocarditis), and confirming that there are no significant artery blockages.

The criteria also require that the affected part of the heart extend beyond the area supplied by just one artery — different from a typical heart attack, which usually damages only the region fed by a single blocked vessel. Doctors also look for new ECG changes with modest troponin elevation.

The treatment: The woman was treated with standard medications for heart failure medical therapy, such as beta blockers, and discharged once she was stable, with a follow-up scheduled at a heart-failure clinic. She resumed her usual daily activities without limitations, and a follow-up ECG showed that her heart's pumping function had recovered to 56%, close to her original baseline.

What makes the case unique: According to the report, takotsubo cardiomyopathy is most often triggered by distressing events, such as the death of a loved one or a serious diagnosis. In this case, though, the trigger was a happy one, which made it an example of "happy heart syndrome," a rare subtype of the condition first described by researchers in 2016. Intense positive emotions can activate some of the same stress pathways in the body that negative ones do, as these cases demonstrate.

Takotsubo cardiomyopathy accounts for an estimated 1% to 3% of cases of acute coronary syndromes, an umbrella term for conditions that involve sudden reduced blood flow to the heart. Within that group, the happy heart variant is rarer still. An analysis of the International Takotsubo Registry, which has data from more than 1,700 broken-heart patients around the world, found that positive emotional triggers were behind about 4.1% of emotionally triggered cases. The large majority were tied to grief, fear or other distressing events.

Compared with the classic symptoms of broken heart syndrome, happy heart syndrome tends to produce a different pattern of heart muscle ballooning that more often affects the middle or base of the heart in addition to the tip. That alternate pattern was not seen in this case, though.

Some research suggests happy heart patients may have milder symptoms and better outcomes than broken heart patients; they have a lower chance of severe heart failure during their hospital stay, for instance. That said, the authors noted that further data is needed to confirm this difference.

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

Can you guess the diagnosis in these strange medical cases? Find out with our diagnostic dilemma quiz!

This picturesque satellite snap shows a "street" of swirling clouds alongside a giant, multicolor plume in the waters between three countries in Asia.

The swirling clouds, known as a Kármán vortex street or von Kármán vortices, were carved out by winds that whipped around a 6,400-foot-tall (1,950 meters) shield volcano, known as Hallasan, on South Korea's oval-shaped Jeju Island. The lofty peak sits in the East China Sea around 60 miles (100 kilometers) south of the Korean Peninsula (top right of the photo) and between China's Jiangsu province (on the left) and Japan's Kyushu island (on the right).

When the winds are just right — between 11 and 34 mph (18 and 55 km/h) — air streams around the elevated peak, creating counterrotating vortices on the leeward side that can sculpt nearby clouds into the swirling patterns we see in this image, according to NASA's Earth Observatory. The three largest swirls collectively stretch roughly 230 miles (370 km) from end to end.

The photo also reveals a thick curtain of brownish sediment stretching beneath the waves along China's eastern coastline, including off Shanghai (located around halfway along the landmass in the image). Most of this sediment was discharged by the Yangtze River, the third-longest waterway on Earth, and similar scenes are visible from space for most of the year.

However, a more distinct plume of yellow and green sediment extends up to 270 miles (430 km) from the coast, appearing to almost touch the von Kármán vortices.

The elongated, pale plume is likely the result of increased turbulence in the Yangtze ‪—‬ caused by high rainfall ‪—‬ coupled with stronger seasonal currents and vertical ocean mixing in the winter, according to the Earth Observatory.

It is not unusual to see von Kármán vortices swirling in the cloudy skies near islands with large peaks, such as Mexico's Guadalupe Island or Spain's Canary Islands. Similarly, large sediment plumes are often photographed by satellites. However, it is much rarer to see such oceanographic and atmospheric phenomena occur side by side.

Jeju Island was created by a submarine volcanic eruption around 2 million years ago and has been inhabited by the Indigenous Jeju people for at least 8,000 years. A 2025 study found that people on the island today have unique genetic mutations leftover from this group, which may help the local Jeju Haenyeo ("women of the sea") free dive for food in deep and cold waters without specialized equipment.

Hallasan (also known as Mount Halla) is the tallest mountain in Korea. It is technically an active volcano, although it has not erupted since A.D. 1007, according to the Smithsonian Institution's Global Volcanism Program. It is renowned for its extensive system of subsurface lava tubes, which are among the "finest" in the world, according to UNESCO.

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