dunes

February 12, 2018

Where dune fields begin

This is the upwind edge of a dune field (825×625 m, 0.51×0.39 mi). Winds blow down a cliff (offscreen) from the lower right, blowing sand toward the upper left. Elongated dunes have formed parallel to the resultant wind direction, only […]
February 5, 2018

Mars’ “Type A” wind

The busy, busy wind has moved a lot of things to make this 0.6×0.85 km (0.37×0.53 mi) landscape. First it built a big dark dune, covering it and the surrounding surface with ripples. Then it dumped a bunch of bright […]
January 22, 2018

Arnus Vallis, Mars

A Piece of Mars: This is a section of Arnus Vallis (scene is 1.25×1 km, 0.78×0.62 mi). It’s a >300 km long valley that was carved out, not by water, but by lava, long ago. Since then the wind has […]
January 18, 2018

Varying wind directions

A Piece of Mars: This 0.5×0.4 km (0.31×0.25 mi) scene shows two dunes near the north pole. The shape of the dunes indicates two main winds: one blowing left to right (which makes slip faces on the right side, one […]
January 8, 2018

Dunes with comet tails

A Piece of Mars: The north polar dunes in this 575×325 m (0.36×0.2 mi) scene are made of dark sand covered by bright winter frost (which will soon sublimate away, as this image was taken in late spring). To the […]
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 […]
September 5, 2017

Leeward and poleward

A Piece of Mars: The sharp line in this 0.625×0.625 km (0.39×0.39 mi) scene is the crest of a long dune in Mars’ southern hemisphere. The sunlit side is also the lee side: the bright streaks are thin sand avalanches […]
August 7, 2017

Exhumed dunes!

A Piece of Mars: The large dunes in the middle of this 375×450 m (0.23×0.28 mi) scene run along a valley (the small dunes at top and bottom are on high ground). What’s amazing about this is that the ends […]
July 31, 2017

Mars’ giant bubble wrap

A Piece of Mars: This 0.7×0.5 km (0.43x.31 mi) scene shows Mars’ giant yellow bubble wrap, with each “bubble” about 100 m across (seriously, don’t you want to pop them?). These are actually a type of dune called a “dome […]