Neverending dust

A Piece of Mars: Some parts of Mars, like this one, are very dusty. This 1.92×1.1 km (1.2×0.67 mi) area has built up a thick deposit of dust that slowly buries the impact craters until they’re mere ghosts of the deep bowls they once were. If you knew the dust fallout rate, you could date

Dune cannibals II

A Piece of Mars: This 0.96×0.54 km (0.60×0.34 mi) scene shows two sets of bedforms (dunes), each aligned in different directions. The more closely-spaced set has sharper crests, and it’s superposed on top of (and it is therefore younger than) the more widely-spaced set. Like a previous post I wrote, the younger set has cannibalized

Wind shadow

A Piece of Mars: There’s a dune field migrating past a 230 m (755 ft) diameter crater, creating a 1.6 km (1 mi) long “shadow” that’s empty of dunes. Why? The rim of the crater pokes up just enough to affect the wind, like pebbles in a stream. Either the sand is diverted around the

Craters and wind

A Piece of Mars: This 90 m (295 ft) crater impacted into a windy, cratered plain. It’s now partly filled with dark sand, but where did that sand come from? Looking closely you’ll see that many of the boulders that were flung out during the impact have little “tails”. These tails show that wind from

Giant “combs” on Mars

A Piece of Mars: This 480×270 m (0.3×0.17 mi) scene shows a herd of 100-300 m fine-toothed combs grazing on the surface of Mars. Wait, what? No, it’s not really combs. This is actually a landscape covered by two sets of windblown bedforms. The larger ones (the “comb” shafts) are very old, now inactive windblown