Colors and waves

A piece of Mars: Here are some lovely ripples on Mars. In the same field of ripples, there are large wavy white ones and small complex blue ones. Why are there two different types, made distinct by their color, size, and shape? Nobody knows, but it’s a good bet the sand grains that they’re made

Mars’ moving dunes

A piece of Mars: Today’s image comes courtesy of my postdoc, Simone Silvestro. He’s studying migrating dunes and has made a 3 image movie of a dune moving across the surface of Mars. This one crawls at a rate of ~0.5 m/year, and it isn’t far from where the Curiosity rover will pass when it

Of sandy lanes

A piece of Mars: Of Sandy Lanes. The yellowish-tan rocks are tall high-standing hills that have been scoured by the wind. Dark sand slowly cuts down the whiter rocks in the valleys, slowly creating majestic lanes bordered by steep, sharp hills. My guess is the sand is moving from top to bottom in this image.

Echoes of the past

These dunes are quite unusual for Mars, and difficult to interpret. The thick blue and white stripes are dunes in their current location, but subtle stripes above them seem to indicate former positions of dunes, small pieces that got left behind as the dunes marched toward the bottom of the image. (HiRISE ESP_022645_1505)