erosion
June 7, 2013
A piece of Mars: In ancient, wind-carved hills, a bluish ribbon of actively moving sand still winds its way. It is a remnant of a long-lived period of wind scour that shaped this landscape. (And it’s been stretched to look […]
May 24, 2013
A piece of Mars: The source of dune sand on Mars is normally something of a mystery. But here on the interior wall of a small crater it appears that small gullies have eroded sediment from the wall and carried […]
May 2, 2013
A piece of Mars. The dark circle (~170 m across) in the middle of the picture is the interior of what used to be a crater. It’s now almost completely eroded away, probably by the wind. Small dunes have formed […]
March 15, 2013
A piece of Mars: Here are some old dunes that look a little like vertebrae of fossils (if you think they look like dragon spines poking out of the ground then you’re playing too many video games). The white areas […]
March 3, 2013
A piece of Mars: As the wind blows sand over terrain, the grains deepen grooves in weak materials, enhancing the topography in the direction of the strongest wind. Here, over eons, sand marching from right to left has formed dunes […]
February 22, 2013
A piece of Mars: Some of the dunes on Mars are just plain weird. Here are some feather-shaped ones. I’m not sure anybody knows why they form these fractal shapes just yet. I don’t know of anything on Earth that […]
February 12, 2013
A piece of Mars: Sandwiched between hills, a huge stepped amphitheater has been carved out of the rock by the wind. The scene is 770×577 m across, with each giant step about 20 m wide. Just imagine a huge concert […]
January 21, 2013
A piece of Mars: What are those dark, flat circles and why are there little dunes sitting on top of them? They’re probably old impact craters that got filled in with dark sediment, and were then eroded flat. So you’re […]
January 8, 2013
A piece of Mars: Dunes don’t usually have a rough surface texture like these do. It’s not clear what’s going on. Are they ancient dunes that are being eroded? What causes this particular texture? It seems unique to high elevations […]