According to research using images from a NASA orbiter, sand dunes in a vast area of northern Mars long thought to be frozen in time are changing with both sudden and gradual motions.

PASADENA, Calif., May 26 /PRNewswire-USNewswire/ -- Data from NASA's Mars Reconnaissance Orbiter (MRO) have helped scientists solve a pair of mysteries dating back four decades and provided new information about climate change on the Red Planet. (Logo: http://www.newscom.com/cgi-bin/prnh/20081007/38461LOGO) The Shallow Radar, or SHARAD, instrument aboard MRO revealed subsurface geology allowing scientists to reconstruct the formation of a large chasm and a series of spiral troughs on the northern ice cap of Mars.

Scientists have reconstructed the formation of two curious features in the northern ice cap of Mars—a chasm larger than the Grand Canyon and a series of spiral troughs—solving a pair of mysteries dating back four decades while finding new evidence of climate change on Mars.

ESA’s Mars Express orbiter imaged the snow-laden region of Rupes Tenuis on the martian north pole on July 29, 2008.

An odd, solitary hill rising part-way down an eroding slope in Mars' north polar layered terrain may be the remnant of a buried impact crater.