superposition

November 17, 2014

Textured gullies

A piece of Mars. These are gullies on a martian hillside (upslope is to the upper right). Water may be what forms the channels, carrying soil and rocks downslope. The textured pattern of the lower slope is caused by the […]
September 22, 2014

Changing winds

A piece of Mars: There are two sets of ripples here: tan ones and gray ones, each oriented to a different wind (scene is 300×225 m, or 984×738 ft). The gray ones sit on top of the tan ones, so […]
August 25, 2014

Which wind came first?

A piece of Mars: This scene (3.9×2.5 km or 2.4×1.6 mi) shows a surface carved by two different winds: one blowing from the right and one blowing from the bottom right. They’ve formed overlapping sets of streamlined rocks called yardangs. […]
March 24, 2014

The millipede, rewritten

A piece of Mars: Looks like a millipede, doesn’t it? It’s something much larger and much less poisonous. It’s an ancient dune (or maybe a ripple) on Mars, that once stretched ~285 m (935 ft) from lower left to middle […]