April 22, 2013
A piece of Mars: Everybody else loves this image because it shows an inverted channel — the remains of a stream that once flowed through this area. But I love it because the little dunes were also formed by a […]
April 16, 2013
A piece of Mars: Is it modern art? Well maybe it looks like it from a distance. Up close, this is reality on Mars. These are dark dunes in the southern hemisphere, awaking from a long hibernation beneath bright winter […]
March 27, 2013
A piece of Mars: There are vast plains on Mars that display criss-crossing streaks like this. These are ~5 m (~16 feet) across, give or take. Did an alien drive a dune buggy all over, leaving behind tracks? Nope. These […]
March 22, 2013
A piece of Mars: Dunes near the north and south poles get cold in the winter, just like they do on Earth. Except on Mars instead of H2O ice, it’s a mix of CO2 and H2O ice (mostly CO2). In […]
March 19, 2013
A piece of Mars: Nili Patera on Mars is an ancient volcano. Some of the old volcanic material has been blown into rather striking sand dunes. It is the first place where dunes were conclusively identified as actively moving. Here’s […]
March 15, 2013
A piece of Mars: Here are some old dunes that look a little like vertebrae of fossils (if you think they look like dragon spines poking out of the ground then you’re playing too many video games). The white areas […]
March 7, 2013
A piece of Mars: Not all piles of windblown sand are able to form proper dunes, with a fully developed avalanche on the downwind side. Here, bluish sand tries to make its way through hilly terrain, which both traps the […]
March 3, 2013
A piece of Mars: As the wind blows sand over terrain, the grains deepen grooves in weak materials, enhancing the topography in the direction of the strongest wind. Here, over eons, sand marching from right to left has formed dunes […]
February 22, 2013
A piece of Mars: Some of the dunes on Mars are just plain weird. Here are some feather-shaped ones. I’m not sure anybody knows why they form these fractal shapes just yet. I don’t know of anything on Earth that […]