Today’s Image of the Day from NASA Earth Observatory features part of the Altai Mountains of central Asia. The photo was captured by an astronaut onboard the International Space Station (ISS).

“In this photo, the late afternoon sunlight casts long shadows onto surrounding snow-covered plains in Mongolia,” says NASA. “The shadows project the general shapes of the mountains, their heights relative to each other, and some details of the ridge crests. Several peaks in this range rise to elevations greater than 3,000 meters (10,000 feet) above sea level; they stand approximately 1,700 meters (5,600 feet) above the plains.”

“The flat plains were formed by sediment that was carried down by the rivers flowing out of the mountains; these are known as alluvial fans. Water from these rivers ultimately flows into Lake Uvs (just outside the right margin of the image), a saline, endorheic lake in this semi-arid region.”

Water from the mountain rivers usually flows underground through the alluvial fans. When the water comes to the surface, it forms a line of springs that is visible from space, explains NASA.

“This spring water also supplies local populations. One of the darker patches along the spring line is the town of Ulaangom (population 31,000), the capital of the Uvs province of Mongolia.”

Image Credit: NASA Earth Observatory 

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By Chrissy Sexton, Earth.com Staff Writer