Chile Volcano Sunsets
But these diffuse plumes also treated Southern Hemisphere denizens to stunning sunsets and sunrises by scattering and refracting incoming sunlight in a way that favors the transmission of light closer to the red end of the spectrum.
This phenomenon can be seen in this image of sunset from New Zealand's Mt. Wellington. [See more sunset images.]
The colorful phenomenon, known officially as a circumhorizon arc, occurs when sunlight strikes cirrus clouds the kind that typically look like cotton candy and form very high in the sky at a certain angle.
The clouds' ice crystals act the same way crystals in a sparkly bracelet or ring might. When light hits the crystals' facets at a certain angle, it is separated out into all the colors in the spectrum.
Arctic Melt Ponds
The sea ice atop the Arctic Ocean can as shown in this photograph from July 12 look quite varied.
The areas of blue in the image are called melt ponds. As ice melts, the liquid water collects in depressions on the surface of the sea ice and deepens them, forming melt ponds.
Researchers on the NASA-funded ICESCAPE mission (Impacts of Climate on Ecosystems and Chemistry of the Arctic Pacific Environment) examined melt ponds, the ice around them and the waters below this summer.
NYC: An Astronaut's View
Snow in the Atacama
The snow came in early July (winter in the Southern Hemisphere), when a cold front dumped up to 80 centimeters of snow (32 inches) on the driest desert in the world.
A Family Portrait
Gigapan of Hurricane Irene's Damage
Hurricane Irene began its Eastern Seaboard onslaught as it approached landfall in North Carolina on Aug. 27. The winds and rains of the hurricane, then a Category 1, battered the Outer Banks. The damage continued with major inland flooding up through the Mid-Atlantic states as well as a significant storm surge in coastal bays and rivers.
Irene made its final landfall at Coney Island in New York City on the morning of Aug. 28 as a strong tropical storm. Its worst effects spared New York, but the storm caused major flooding in states across the Northeast.
Arctic Camera Traps
In this shot, a grizzly bear is sniffing around close to the camera.
Siberian Snow Leopards Spotted
The cats were spotted at an altitude of about 13,100 feet (4,000 meters) on the Chikhachyova Ridge in the Altai Republic, a semiautonomous region in southern Russia.
In addition to the snow leopards, the cameras caught images of a rarely seen Pallas cat, also called a manul, a thick-furred feline about the size of a domestic cat.
Indian Ocean Clouds
The natural-color image was captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite on November 30, 2011. According to Patrick Minnis, a cloud expert at NASA's Langley Research Center, there are at least three layers of clouds in the image.
Pine Island Glacier Crack
The crack portends the calving of an iceberg from the glacier, which last happened in 2001.
Pine Island Glacier is of particular interest to scientists because it is big and unstable and so is one of the largest sources of uncertainty in global sea level rise projections.
These events yielded images that awe and amaze, that show the scale of the forces that shape our planet and the majesty of the landscapes on its surface. Here, we take a look back at some of the most amazing images of the year.
On the Eve of 2011
The flare triggered northern lights displays for skywatchers living in northern latitudes and graced with clear skies, including Tom Eklund of Finland, who took this photo on Feb. 14. [More aurora images.]
Japan Tsunami Damage
The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite observed dramatic changes at Rikuzentakata, including in this ASTER image taken on March 14. [Video: Before and After the Tsunami]
ASTER combines infrared, red, and green wavelengths of light to make false-color images that distinguish between water and land. In these images, water is blue. Buildings and paved surfaces appear in shades of blue-gray. Agricultural fields range in color from brown to beige to pink. Vegetation is red, and brighter shades of red indicate more robust vegetation.
In the wake of the tsunami, the coastline of Rikuzentakata was totally reshaped. A long barrier island of well-vegetated land, visible in 2007, is almost completely gone from the waterfront. North of that, flood water sits on agricultural fields. East of Rikuzentakata, a large mass of peach-colored floating debris appears in the image from 2011.
East Coast Lights at Night
In contrast to the city lights along the sea coast and interior, the Atlantic Ocean appears as a featureless dark region filling the lower right quarter of the image.
The telescope was shut down when the observatory lost power on April 11, as wildfires knocked out power lines in the area. The observatory's dome was shut and backup generators powered the facility.
The wildfires burned more than a million acres of the state.
The formation is called an undular bore, or gravity wave train, and it appears as rarely as once a month. An undular bore is a disturbance in the Earth's atmosphere that can be seen as clouds move in waves. They normally occur within an area of the atmosphere that is stable in the low levels after a cold front moves through.
In the days after the image was taken, water levels continued to rise in Vicksburg. By 9 a.m. on May 12, the river had reached 54.51 feet and was still rising. The river reached flood stage at 43 feet, and major flood stage at 50 feet. The record is 56.2 feet, reached on May 4, 1927.
This year's flooding was some of the worst on the Mississippi in U.S. history.
Joplin Tornado Track
The storm was three-quarters of a mile wide with a 300-yard-wide (274 meters) hurricane-like eye. Its winds exceeded 200 mph (322 kph). The tornado was on the ground for 6 miles (9.7 kilometers).
Ash-Spewing Eruption in Chile
The spewing volcano emitted ash to a maximum altitude of 45,000 feet (14,000 meters), according to the Buenos Aires Volcanic Ash Advisory Center (VAAC). The ash plume remained at or above 40,000 feet (12,000) for at least the next two days.