December 19, 2012
A piece of Mars: On Earth, it’s typically water that erodes a landscape, as rivers cut down rocks, storms trigger landslides, and ocean waves eat away at shorelines. On Mars, it’s usually the wind that slowly grinds down a landscape. […]
December 16, 2012
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 11, 2012
A piece of Mars: Small dunes or ripples in a depression provide a striking contrast with the surrounding bedrock. The sand in the dunes changes color, too, to mark off which regions have more recently been actively moved by the […]
December 6, 2012
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
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, […]
November 20, 2012
A piece of Mars: Some places on Mars highlight just how effective the wind is at sculpting the surface. This is a good example. Dark and light stripes on the right show not one but two successive influxes of sand: […]
November 12, 2012
A Piece of Mars: A large dune (on the right, bluish) rests on a surface covered in much smaller dunes or ripples (on the left, cream). This is part of my favorite dune field on Mars. Can you spot the […]
November 1, 2012
A piece of Mars: When the wind blows sand up against obstacles like this bright little hill, the sand is swept around to the sides. This leaves a wind shadow in the wake of the hill. It’s one of the […]
October 9, 2012
A piece of Mars: I just adore that the wind can do this to a landscape. Over a long period of time, two different winds have scratched deep grooves in a rocky surface. Wind-carved rocks like this are called “yardangs”. […]