Image of the Day Archive
Above: Warning: Bison in rear view mirror may be closer than they appear.
The driver of the car in the above undated photo found this out first-hand when the car was caught in a bison "traffic jam" in Yellowstone National Park.
The bison is the largest land mammal in North America. They can weigh more than half a ton. Despite their size, bison can run up to 30 mph (50 km/h). That's more than fast enough to keep up with traffic on wintery roads in Yellowstone.
This herd was large enough to intimidate, but it's a mere fraction of the Yellowstone bison population, which fluctuates between 2,300 and 4,500 animals. There are two subpopulations within Yellowstone bison, the Northern Range and Hayden Valley herds, which are divided based on their gathering for breeding.
Bison were nearly extinct in the 19th century due to hunting, slaughter and bovine diseases from domestic cattle. Today, Yellowstone is the only place in the lower 48 states where a population of wild bison has persisted since prehistoric times.
Follow OurAmazingPlanet @OAPlanet, Facebook & Google+.
Among the Mangroves
The Everglades are complex system of interdependent ecosystems, including marshes, swamps, mangrove forests and rocklands.
Everglades National Park protects 20 percent of the original Everglades. The national park attracts about a million visitors each year, and is the third-largest national park in the lower 48 states, according to the National Park Service. Everglades National Park, which was established on Dec. 6, 1947, has also been declared an International Biosphere Reserve, a World Heritage Site and a Wetland of International Importance. [Related Photos: Giant Pythons Invade Everglades]
An Astronaut's View
La Malinche is a so-called stratovolcano, located approximately 19 miles (30 kilometers) northeast of Puebla, Mexico. Stratovolcanoes are steep, conical structures that are composed of layers of ash, lava and rocks that were released from previous explosive eruptions.
An examination of volcanic rocks at La Malinche suggests the structure erupted near the end of the 12th century. Researchers have also found evidence of mudflows that indicate an eruption occurred about 3,100 years ago, which would have affected Pre-Columbian settlements in the nearby Puebla basin, according to NASA. [Related: The 10 Biggest Volcanic Eruptions in History]
Postcard From An Expedition
A team of 49 scientists and 44 crewmembers embarked on a three-month expedition to Antarctica in June. The researchers examined properties of Antarctic sea ice and studied changes in the region's ecosystems. [Related: Extreme Living – Scientists at the End of the Earth]
Seal of Approval
The WCS is studying southern elephant seals as part of the organization's Sea and Sky project, which helps protect the Patagonian Sea and its surrounding coastal regions, which make up one of the largest and richest marine ecosystems in the world. [Related Photos: Elephant Seals of the Antarctic]
Sea of Fog Shrouds Grand Canyon
This breathtaking fog filled the Grand Canyon last week, transforming the rocky Arizona landmark into something seemingly coastal. The fog formed during a rare weather event known as a temperature inversion, which happen just a few times each year.
Calm winds, clear skies and long winter nights are ideal conditions for temperature inversions. When these conditions mingle, a layer of cool air at the canyon floor can become trapped underneath warmer air. This is opposite of the usual weather pattern, since temperature generally decreases with altitude. When moisture is trapped in this cool layer of air, fog can form.
Last week, a text-book temperature inversion in the Grand Canyon created a sea of fog across the 18-mile-wide (28.9 kilometers) gap, which was carved by Colorado River and stretches 277 miles (446 km). [Related: 7 Amazing Grand Canyon Facts]
Follow OurAmazingPlanet @OAPlanet, Facebook & Google+.
Eyes Over Antarctica
In five science flights, totaling 43 hours, the researchers collected data over more than 12,000 miles (20,000 kilometers). This photo, taken on Nov. 24, shows a so-called lenticular cloud hovering near Mount Discovery, a volcano located about 44 miles (70 km) southwest of McMurdo Station on Antarctica's Ross Island.
Lenticular clouds form when a layer of air near the surface encounters a topographic barrier, gets forced upward, and flows over it as a series of atmospheric gravity waves. The clouds form at the crest of the waves, where the air is coolest and water vapor can condense into cloud droplets.
The Antarctic flights were part of NASA's Operation IceBridge, a multi-year mission to monitor ice conditions in Antarctica and the Arctic. [Related: Stunning Photos of Antarctic Ice]
Glacier National Park encompasses a 1,500-square-mile (4,000 square kilometers) area, which includes forests, lakes, mountains and alpine meadows. In this photo, Mount Cleveland, the highest mountain in Glacier National Park, can be seen on the left. [Related: All Yours: 10 Least Visited National Parks]
Rock-A-Bye Baby Sloth
Sloths are native to Central America and northern South America, including portions of Peru and central Brazil. These nocturnal animals typically sleep for 15 hours or more each day, and are notoriously slow-moving.
Two-toed sloths have long limbs with two curved claws on its front feet and three on its hind. This enables them to hang upside down from tree limbs, and move deftly through tree tops and canopies. [Related: World's Cutest Baby Animals]
It's the Most Wonderful Times of the Year
If you're in Idaho, Minnesota, Maine or upstate New York, you may be in luck this holiday season. Areas around the Rocky Mountains, Sierra Nevada Mountains and the Allegheny Mountains of Pennsylvania and West Virginia may also be in store for a white Christmas.
The map displays the historic probability of there being at least 1-inch (2.5 centimeters) of snow on the ground in the lower 48 states on Dec. 25. The dark gray patches show places where the probability is less than 10 percent, while the swirls of white on the map indicate places where the probability is greater than 90 percent.
NOAA's National Climatic Data Center used weather data from 1981 to 2010 to build the festive map. To keep track of snowfall across the U.S. on a daily basis, the NCDC also maintains a daily snowfall map. [Related: Top 11 Christmas Gifts for Geeks]
Dreaming of a White Christmas in Arches National Park
The park, in Moab, Utah, is under a winter advisory as many trails are snowy, icy and dangerous, according to the park's website.
Arches National Park is known as a landscape of contrasting colors, and the red rocks and white snow make that even more apparent in winter. In this park, visitors will also find landforms and textures unlike any other in the world.
The most famous feature in Arches National Park is the Delicate Arch, a 65-foot-tall (19.8 meters) freestanding natural arch. Delicate Arch is so famous that it's on Utah's license plates.
The park has over 2,000 natural stone arches, in addition to hundreds of soaring pinnacles, massive fins and giant balanced rocks. This red rock wonderland will amaze hikers with its formations, trails, sunsets ... and snow.
Sunlight and Snow
The volcanic islands visible in this image, Carlisle, Cleveland and Tana. The Carlisle and Herbert are volcanoes are form separate islands, while the Cleveland and Tana volcanoes form the eastern and western ends, respectively, of Chuginadak Island. A layer of low clouds covers the sea surface and much of the lower elevations of the islands, exposing only the snow-covered peaks. [Related: 50 Amazing Volcano Facts]
Majestic Glacier Bay
More than 400,000 people visit Glacier Bay National Park each year. Since no roads lead into the park, it is typically accessed by plane or cruise ship. Visitors to the pristine park share the area with diverse wildlife, including grizzly and black bears, moose, wolves, mountain goats, sea otters, whales, eagles and deer. [Related: One-of-a-Kind Places on Earth]
Twin Tropical Cyclones
Gaia will pinpoint the locations of 1 billion stars in the Milky Way, and will collect information on their brightness and motion. This $1 billion mission will help researchers better understand the history of the universe, according to officials at the European Space Agency.
In about three weeks, Gaia will settle into a gravitationally stable spot known as the sun-Earth Lagrange Point 2 (L2), which is located roughly 930,000 miles (1.5 million kilometers) away from Earth. [Related: Milky Way Quiz: Test Your Galaxy Smarts]
Grand Teton National Park Glistens In the Snow
Located in northwestern Wyoming, Grand Teton National Park protects stunning mountain scenery and a diverse array of wildlife. Rising more than 7,000 feet (2,134 meters) above the valley of Jackson Hole, the Teton Range dominates the park's skyline. Protecting these breathtaking mountains was the impetus for the creation of Grand Teton National Park, where visitors can explore over 200 miles (300 kilometers) of trails, float the Snake River or enjoy the serenity of this remarkable place. The granite and gneiss composing the core of the Teton Range are some of the oldest rocks in North America, but the mountains are among the youngest in the world.
Long, snowy and bitterly cold winters make the climate of Jackson Hole unforgiving. Snow often blankets the landscape from early November to May. Last week’s minus 20 F temperature is not even close to the coldest temperature ever recorded in Grand Teton National Park, which was minus 63 F (minus 53 C).
Follow OurAmazingPlanet @OAPlanet, Facebook Google+.
White House Tradition
A Rainbow of Wavelengths
As SDO gazes at the sun, the telescope can "see" in a wide range of wavelengths that are invisible to the naked eye. These different perspectives help scientists track how particles and heat move through the sun's atmosphere, since each wavelength of light represents solar material at specific temperatures. [Related: Latest HD Photos From the Solar Dynamics Observatory]