Tag Archives: dunes

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 ...

The long, low dune

A piece of Mars: A long, low dune covered in long, linear ripples stretches across the scene (600x450 m; 1969x1476 ft). Dark gray areas on the dune show where sand has most recently moved. A small slip face has formed ...

Aeolian shoreline

A piece of Mars: On the left is a steep slope leading to a hill. On the right are waves - but not waves of water or any other kind of liquid. These are dunes or very large ripples, blown ...

Lumpy bumpy dunes

A piece of Mars: These funny shaped dunes were formed by winds blowing from two directions - one from the top of the frame and one from the upper right. Both winds make steep slopes (slip faces) on the downwind ...

What on Mars?

A piece of Mars: What on Mars is this (the scene is 600x450 m, or 0.37x0.28 mi)? It can be hard to tell. The lines are ridges of windblown dunes or ripples, the dark gray stuff is active sand blowing ...

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 ...