Tag Archives: dunes

Stealth bomber dunes

A piece of Mars: These dunes look strangely triangular, a little bit like a flock of stealth bombers. Why? They're two-faced barchans. Each flat face is an avalanche slope that faces downwind, formed by one of two distinct wind patterns ...

Dust devils and wind scours on ripples on dunes

A piece of Mars: So much wind. There are dark swirly tracks of dust devils that have passed by, ripples covering dunes, wind scours around rocks, and of course dunes. Dune crests have a different color than other regions: are ...

Frosty dunes

A piece of Mars: In this image (0.96x0.54 km or 0.6x0.33 mi), it's late winter and the sun is barely above the horizon here near the north pole. The dunes are covered in winter frost, most of which is CO2 ...

Small dunes on Mars

A piece of Mars: These dunes are some of the smallest on Mars. The smallest in this frame is ~150 m long (492 ft). But the smallest Earth dunes are ~20 m across. Why are they so much bigger on ...

The looming dune

A piece of Mars: this 0.96x0.54 km (0.6x0.33 mi) scene shows a large, rippled dune that is slowly marching towards the upper right. The smooth striped band running from upper left to lower right is the slip face, where sand ...

Wind stripes

A piece of Mars: Yes, I post a lot of pictures of martian dunes with striped patterns. They're all distinct and beautiful. So here's another one, 480x270 m (0.3x0.17 mi) in size. These beasts moved from right to left across ...

Melty dunes

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 600x450 m (0.37x0.28 mi) ...

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A piece of Mars: Ripples form endless chevrons in this 600x450 m (0.37x0.30 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 ...

The bright barchan

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 ...

Sometimes I just have no idea

A piece of Mars: The smooth areas are eroded dunes, separated by fields of boulders (the scene is 1.51x1.14 km or 0.93x0.71 mi). The largest boulder near the center is 7.5 m (25 ft) across, the size of a small ...