Tag Archives: dunes

Whither the wind

A piece of Mars: Which way did the wind blow here? You can tell by looking at the dune and its ripples. The slip face (the avalanching slope of the dune) faces downwind, so the strongest wind here mainly blows ...

When Mars gets weird

A piece of Mars: Mars can be a strange place. This is actually a sand dune on Mars not far from the north pole. Here it's imaged in the springtime when the dunes are still covered inĀ  bright CO2 frost, ...

Lighting effects

A piece of Mars: It's winter in the southern hemisphere, and dunes like these are covered in bright white CO2 frost. The sun is near the horizon (shining from the top of the image), so it creates stark shadows. That ...

Swoosh

A piece of Mars: What is this big swoosh? It's a big dark dune. The dark/light striping across it is found in all of the dunes in this area, but what is it? We're probably seeing the inside of the ...

Yes, this is a bit of windy Mars. Really.

A piece of Mars: Yep, this is really Mars. It's a tiny bit (600x450 m) of the southwestern side of a large dune in the southern midlatitudes. The dark lines are furrows that are thought to be carved by blocks ...

Lines, lines

A piece of Mars: On martian dunes it's all about lines, lines, lines. The prominent wavy ones on the left are thought to be erosional scars left by sliding blocks of dry ice. The little fingerprint-like lines are ripples, like ...

Wintery dune

A piece of Mars: A single dune sits on the surface of Mars, not too far from the north pole. It's early spring, but this far north the dune is still covered in white CO2 frost (as well as a ...

Are you being oblique?

A piece of Mars: Barchan, or crescent dunes, are generally thought to form from winds blowing from a single direction. Reality isn't usually that nice. Here are two barchans with crescent-shaped slip faces on their eastern (right) sides, indicating that ...

Waiting for spring

A piece of Mars: These sharp-tipped hills are dunes near the north pole of Mars. At the height of summer they're lovely dark dunes, but because it's just barely spring here they're still covered in white frost (mostly CO2 ice, ...

Martian sports

A piece of Mars: In the center are two dark dunes, racing one another to jump over hurdles formed of older, now inactive dunes (or maybe those bright things are ripples, we still don't know for sure). The dune in ...