December 26, 2017

Buried by ejecta

A Piece of Mars: To see this one well you’ll have to click on the image. At the lower right, a 240 m (787 ft) diameter crater formed when a bolide hit the surface, throwing out ejecta on the surrounding […]
December 18, 2017

The mysterious bright streaks

A Piece of Mars: Some things just go unexplained (so far, anyway). Here’s a mysterious bright streak (scene is 1.2×1.8 km, 0.75×1.12 mi) concentrated between two sets of ripple-like bedforms. It looks sort of like a river, but it’s on […]
December 11, 2017

Dunes in a row

A Piece of Mars: Look at the alignment of the ~100 m dunes in this 713×750 m (0.44×0.47 mi) scene. How do dunes form in such straight lines? And why don’t they always do that? It’s likely that these dunes […]
December 4, 2017

Ripples of rock

A Piece of Mars: To the upper right of this 0.85×0.6 km (0.53×0.37 mi) scene is a flat-lying plain strewn with large ripples. To the lower left is a rugged hill with gray rock laced with white veins (this might […]
November 27, 2017

The corpse of a dune

A Piece of Mars: The rippled darker patch in this 600×600 m (0.37×0.37 mi) scene is the former site of a sand dune. This is one of a few “dune corpses” found just upwind of a dune field in Holden […]
November 20, 2017

Is it windblown or not (#2)?

A Piece of Mars: This 0.93×1.25 km (0.57×0.78 mi) scene shows what I’m starting to think are windblown features. I posted something similar to this once before, from a location not that far from here. In this one region of […]
November 15, 2017


A Piece of Mars: There’s a fabric of erosion in this 1×1 km (0.62×0.62 mi) scene, with the main wind blowing from lower right to upper left (and if you look carefully you’ll see there’s a second, subtler fabric a […]
November 8, 2017

Island in the stream

A Piece of Mars: In the floor of what might have been an old fluvial channel there are a bunch of really neat dunes (or maybe ripples, they’re TARs and we don’t know yet what they are). One spire pokes […]
November 6, 2017

Black and tan

A Piece of Mars: Dunes in the top row in this 0.73×0.47 km (0.46×0.29 mi) scene are dark but those in the lower row are brighter. Why? They’re all probably made out of the same kind of sand, which is […]