Avalanches On Mars: Spring Thaw Erodes Sand Dunes (PICTURES)
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The surface of Mars is constantly changing due to the planet's seasonal patterns.
High resolution images captured by NASA's Mars Reconnaissance Orbiter show the effects of the passage of time on the basalt sand dunes located near the red planet's north pole. According to the images, these dunes shift and reform--just like those on Earth.
It was previously though that this dune sea, which covers an area about the size of Texas, was a fairly static region. But new research shows that wind and seasonal erosion can physically transform the area from year to year. According to Discovery News, "The research includes tracking climate and environmental processes active on Mars today, so scientists can figure out what might have been different in the past, when Mars was warmer, wetter and more hospitable for life as we know it."
Take a look through the slideshow (below) to see changes in the dunes near Mars's north pole. Then, check out our slideshow of more extraordinary images of Mars, as well as NASA's most stunning images from 2010.
These images show the gradual erosion of a single Martian sand dune. The top image was captured on June 17, 2008 and the bottom was captured on July 2, 2010 (a period of time equal to roughly one Martian year). Both images were captured during the warm period of the year, when the dune's winter coating of carbon-dioxide ice has thawed. New alcoves, seen on the dune in the bottom image, were formed when melting ice loosened the sand and caused small <a href="http://www.huffingtonpost.com/2008/03/04/spacecraft-photographs-ma_n_89725.html" target="_hplink">avalanches</a>, changing the face of the dune.
Winter Freeze Evaporating
This image (captured Feb. 23, 2010) shows the same dune during the early stages of the springtime thaw. The dune's layer of carbon-dioxide ice has only just begun to melt. The dark streaks show fresh avalanches on the dune's slipface.
Dune Field With Ice
The same ongoing process can be observed on various dunes throughout the planet's northern dune field. This false-color image, acquired in Janauary 2010, shows the dunes covered in winter ice.
Dune Field Without Ice
The dark streaks show where melting ice caused avalanches that changed the shape of some dunes. Wind sometimes sweeps through the region and erases the evidence of avalanches.