March 18, 2015
A Piece of Mars: With all due apologies to followers of the show Coupling, I have to call these things “melty dunes”. This link shows what a crisp dune should look like. The dunes in this 600×450 m (0.37×0.28 mi) […]
March 9, 2015
A piece of Mars: Ripples form endless chevrons in this 600×450 m (0.37×0.30 mi) scene. It’s really the crest of a dune that connects all the vertices in the chevrons, making that straight line that runs nearly vertical through the […]
February 17, 2015
A piece of Mars: Most dunes on Mars are dark, like these and these. So why is this one bright? It’s adjacent to a more typical, dark dune. It’s possible that there are two populations of sand here that are […]
February 9, 2015
A piece of Mars: The smooth areas are eroded dunes, separated by fields of boulders (the scene is 1.51×1.14 km or 0.93×0.71 mi). The largest boulder near the center is 7.5 m (25 ft) across, the size of a small […]
February 2, 2015
A piece of Mars: What happens to dunes as they move over rough terrain? This is what a barchan looks like on a relatively flat surface. If the hills are smaller than the dune, then it does its best to […]
January 26, 2015
A piece of Mars: This scene (600×450 m or 1969×1476 ft) is covered in small craters, formed by the splash of a larger crater nearby. They cover everything, even the bright ripples visible on the right. So the ripples were […]
January 21, 2015
A piece of Mars: The curving ridge of a mountain has signs of many small landslides. Mantled on top of these is an older set of landslides that has been partially eroded away. The rippled edge of this older deposit […]
January 12, 2015
A piece of Mars: This 600×450 m (1969×1476 ft) scene has a complex sedimentary history. How are bearded craters and dunes formed? They weren’t always bearded. At some point, a deposit of bright material accumulated on this surface, and was […]
January 5, 2015
A piece of Mars: A long, low dune covered in long, linear ripples stretches across the scene (600×450 m; 1969×1476 ft). Dark gray areas on the dune show where sand has most recently moved. A small slip face has formed […]