As a mountain stream moves into a flat area, it slows down and loses its capacity to carry as much alluvium as it did upstream, depositing the excess in sandbars throughout the channels. Over time, the channel migrates back and forth, creating fan-shaped deposits known as alluvial fans.
Located in southeastern India, Chilika is best known as a mecca for birds, which are attracted by the hundreds of species of fish and other aquatic life. During peak migratory season, the lake hosts more than 1 million birds from more than 200 species. Also, the number of shrimp farms around Chilika has increased dramatically in recent decades.
Lightning flashes occur 4.3 million times a day on Earth. The Firestation, a new instrument aboard the International Space Station, includes photometers to measure lightning flashes, radio antennas to measure the static (a proxy for the strength of the electrical discharge) and a gamma-ray electron detector.
This sector of the Green River canyon in eastern Utah is known as Bowknot Bend because of the way the river doubles back on itself. The loop carries river rafters 14.5 kilometers (9 miles) before bringing them back to nearly the same point they started from—though on the other side of a low, narrow saddle.
An image of the Amazon acquired from NASA’s MESSENGER satellite shows how substituting an infrared sensor for a blue one renders a crisper image of plants and trees from space and offers valuable information about plant health.
A whopping 68 million metric tons of material sliding down the flanks of Alaska’s Mount La Perouse on Feb. 16, 2014, potentially makes this the largest-known natural landslide on Earth since 2010.
A gloomy icon of its depressed population, North Korea is almost completely blacked out at night compared with the bright city lights in neighboring South Korea and China. In this astronaut photo taken from the International Space Station, the darkened country strangely appears as if it is a patch of water connecting the Yellow Sea to the Sea of Japan.
Since its launch on Feb. 11, 2013, scientists have been working to understand Landsat 8 Earth observation satellite data. Some have been calibrating the data—checking them against ground observations and matching them to the rest of the 42-year-long Landsat record. At the same time, the broader science community has been learning to use the new data.
Sochi is a summer resort town with a warm, humid, subtropical climate. But the cold alpine climate of the Caucasus Mountains lies just a short distance inland. Nature helped the Olympic hosts in 2014 with cold weather and some natural snow during the weeks prior to the games.
On Jan. 19, 2014, NASA’s Aqua satellite captured an image of a bloom of microscopic organisms off the southeastern coast of Brazil. Biologists working in the area have identified the bloom as a fast-swimming ciliate protist. Though it is not a true phytoplankter, it is an autotroph, i.e., it makes its own food.