dunes

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 10, 2013

Rainbow dunes on Mars

A piece of Mars: The dark dune here seems to have a subtle rainbow color across it. Is it a real rainbow? Well, no. Part of it is that I’ve stretched the image to enhance color, so the dark dune […]
February 1, 2013

Dunes. Just dunes.

A piece of Mars: These large dunes are located in Kaiser crater, a big crater in the southern midlatitudes. The scene is 789×592 m across. Imagine standing on one of these monsters, and seeing nothing but pristine ripples criscrossing all […]
January 21, 2013

Circles

A piece of Mars: What are those dark, flat circles and why are there little dunes sitting on top of them? They’re probably old impact craters that got filled in with dark sediment, and were then eroded flat. So you’re […]
January 11, 2013

Bright and dark sand on a dune

A piece of Mars: A lovely little dune is right at the edge of this image, trying its best to migrate into the center of the frame. The bright sickle-shaped part of the dune is its slip face, where sand […]
December 31, 2012

Dune cannibals

A piece of Mars: Dunes often cannibalize each other, with new dunes forming from the sand in older dunes. Here the tan dunes have formed from the sand that made up the grayish blue dunes. Notice the banding on the […]
December 16, 2012

Wisps

A piece of Mars: These wispy dunes look like veins on a leaf, don’t they? The thicker ones are older, and they are slowly being reworked by the younger, thinner ones. If they remain active, then the smaller ones will […]
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 […]
November 25, 2012

And the wind blew on

A piece of Mars: Small dunes (or possibly ripples) are likely no longer moving in today’s winds. Or are they? Dark splotches on their upper (northern) sides suggest some kind of wind scour has recently occurred. Winds blow, create dunes, […]