ripples

April 25, 2016

Old ripples

A Piece of Mars: In this 480×270 m scene (0.3×0.17 mi), there are a bunch of “ripples” spaced by 5-20 m (the quotes are because we don’t know yet if these are ripples, dunes, or some other new kind of […]
April 19, 2016

Stripes by wind and gravity

A Piece of Mars: This scene (800×450 m or 0.5×0.28 mi) is a steep slope, with high rocky outcrops on the upper right and both gullies and ripples heading downslope to the lower left. The wider, brighter stripes are gullies […]
March 28, 2016

Three types of windblown piles of stuff

A Piece of Mars: The wind blows different sorts of sediment in different ways. Ultimately they pile up because some oddity in nature makes one spot accumulate more sediment than other spots, allowing that windblown pile of stuff to grow. […]
March 7, 2016

How far does the wind blow stuff?

A Piece of Mars: Hargrave crater has an amazing array of colorful surfaces, each of which reflects a different type of rock (this scene is 480×270 m or 0.3×0.17 mi). I like the ripples sitting on top of it all; […]
January 25, 2016

Remnants of erosion

A Piece of Mars: The gray area in the center of the 480×270 m (0.3×0.17 mi) area is an erosional remnant: once, more of this area was covered by the gray stuff, but some of it has eroded away (most […]
December 21, 2015

Curiosity about sand dunes (part 2/2)

Today is December 21, 2015 (northern winter and southern summer solstice on Earth). On Mars it is Ls = 84º, Mars Year 33 (about 12 sols from northern summer and southern winter solstice on Mars). It is sol 1200 of […]
December 14, 2015

Curiosity about sand dunes (part 1/2)

Sorry for the pun in the title there, but NASA asked for it by naming their rover like that. And you’ve seen it done a hundred times, so let’s grit our teeth, smile, and carry on. Anyway. So I’m more […]
November 24, 2015

Too steep for ripples

A piece of Mars: This 480×270 m (0.3×0.17 mi) area is a steep slope that plunges down to the upper left. A pile of dark sand, covered by brighter tan dust, clings to the hillside. Usually the martian wind blows […]
November 17, 2015

Windy windows

A Piece of Mars: This 0.96×0.54 km (0.6×0.33 mi) area shows ripples forming on a layer of dark gray material. In a few spots, the gray layer has been eroded away (probably by wind scour), revealing the lighter, tan-colored terrain […]