Tag Archives: stabilized

June 17, 2013

Hills, boulders, and wind

A piece of Mars: In the lower left of the image, a small hill stands above a plain partly covered by stabilized ripples. Boulders have rolled down the hill as it slowly erodes. If these ripples aren't ever activated by ...

April 22, 2013

Topography and the wind

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 ...

March 15, 2013

Spines

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

Almost a dune

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 ...

February 22, 2013

Those feathery bright dunes on Mars

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 ...

February 19, 2013

Drifting sand

A piece of Mars: Dark sand has been blown into the scene from the upper right. It has piled up against older, brighter dunes that may now be inactive. The sand drifts on and on, piling up where the wind ...

February 3, 2013

Dunes being buried

A piece of Mars: Most dunes on Mars are the freshest, youngest features around. Not so here. The bright dunes near the bottom here are slowly being buried by debris coming down from the gullies on the slope, coming from ...

January 8, 2013

Mysterious textures

A piece of Mars: Dunes don't usually have a rough surface texture like these do. It's not clear what's going on. Are they ancient dunes that are being eroded? What causes this particular texture? It seems unique to high elevations ...

December 11, 2012

The Painted Desert, on Mars

A piece of Mars: Small dunes or ripples in a depression provide a striking contrast with the surrounding bedrock. The sand in the dunes changes color, too, to mark off which regions have more recently been actively moved by the ...

December 6, 2012

Crescents and ripples

A piece of Mars: A lonely dune slowly makes its way (towards the upper right) across a plain. Well, look closer, it's not all that lonely. Surrounding it on the plain are smaller streaks that are ripples, which also once ...