Dune Mix-up

Credit: NASA/JPL/University of Arizona

Fly over this image of sand dunes in the cen­tral part of Her­schel Crater and you’ll see a jum­bled mix of dune­fields.

Long stream­ers, resem­bling some sort of flame-headed alien with its arms out­stretched, called lin­ear dunes dom­i­nate the cen­ter of the image taken by the HiRISE cam­era aboard the Mars Recon­nais­sance Orbiter. On Earth, lin­ear dunes result when sand is pushed from two pre­vail­ing wind direc­tions and meet at an angle of less than 90 degrees. In some areas, lines of sand com­pletely fill and cross the ancient craters of Mars.

Explore the image a lit­tle more and you’ll find crescent-shaped barchan dunes. The horns of the cres­cent point down­wind. The steeper and tallest part of the dune faces into the wind. In this image, sci­en­tists believe that high winds from the north, or top, formed these dunes. On Earth, we find barchan sand dunes in areas where there is lit­tle sand in rocky areas.

Explor­ing and study­ing wind pat­terns on Mars will help sci­en­tists iden­tify suit­able places to land future space­craft and per­haps estab­lish human out­posts. Her­schel Crater is a large crater on Mars named after the eigh­teenth cen­tury astronomer, William Her­schel. The crater is more than 300 kilo­me­ters across (about 186 miles). It is found in the cratered high­lands of Mars’ south­ern hemisphere.