Tag Archives: crater

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 ...

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 ...

Old ripples

A Piece of Mars: In this 480x270 m scene (0.3x0.17 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 ...

Martian lace

A piece of Mars: This 300x300 m (984x984 ft) scene shows bright windblown dunes or ripples arrayed in a lacy pattern (the biggest ones are about 5 m, or 16 ft, across). This is near the landing site of Ares ...

Flow

A piece of Mars: Below this ~550 m (0.3 mi) wide crater lies a ~1.3 km (0.8 mi) long "beard", the wake of an ancient flow around the crater. Based on its location on Mars, I'm guessing the fluid flowing ...

On Mars, the wind wins

A piece of Mars: This scene (600x450 m or 1969x1476 ft) is covered in small craters, formed by the splash of a larger crater nearby. They cover everything, even the bright ripples visible on the right. So the ripples ...

Bearded craters and dunes

A piece of Mars: This 600x450 m (1969x1476 ft) scene has a complex sedimentary history. How are bearded craters and dunes formed? They weren't always bearded. At some point, a deposit of bright material accumulated on this surface, and was ...

Wind, wind, impact(!), and then more wind…

A piece of Mars: Some time ago, something hit the ground on Mars and made this impact crater, right into a field of ripples. Stuff thrown up during the impact fell back down, burying the ripples with the gray ejecta ...

Inverted crater

A piece of Mars: This circular hill is 200 m (~656 ft) across and ~48 m (~160 ft) high. It stands alone on a relatively flat plain. Why is it there? The surface here used to be ~48 m higher ...

Wind within vs. wind without

A piece of Mars: Dunes outside the crater are straight but the ones inside the crater look like a spiderweb. Why? This image shows just how much the topography of a crater wall can affect the wind, which produces a ...