mars
July 14, 2012
A piece of Mars: What makes a dune different from a random pile of sand? Usually the requirement is that it has a “slipface”, a steep avalanching slope. The central dune in the image here has a small one, making […]
July 11, 2012
A piece of Mars: Dunes near the north pole of Mars form in a very cold environment. Winter ice continually tries to stop them in their tracks, which makes for unusually rounded dunes like these. (HiRISE ESP_027451_2635)
July 10, 2012
A piece of Mars: What an intriguing mess this is. These are dunes or ripples, oriented every which way, and mottled with white spots. The different orientations tell us that the winds blow from several different directions, on timescales long […]
June 4, 2012
A piece of Mars: You can’t easily tell here, but you’re looking at a steep slope that is high at the bottom of the image and flattens out at the top of the image (the small dunes at the top […]
May 30, 2012
A piece of Mars: I know, I keep showing ripples. But they’re all so different. This one has a distinct swirl appearance, like it’s stretched and twisted taffy. The complexities of the winds that create these things are not at […]
May 29, 2012
A piece of Mars: Back in 2007, the Mars Exploration Rover Opportunity spent a great deal of time investigating the rim of Victoria crater. Here is the northern rim of the crater, showing three dark (bluish) sandy streaks formed by […]
May 28, 2012
A piece of Mars: My brain keeps seeing it as stuffed pillows, but it’s the other way around — the sun is coming from the upper left, so the centers of the little polygons are low and their edges are […]
May 27, 2012
A piece of Mars: Small, dark ripples have overridden larger, bright ones. The larger ones have some interesting shapes — arcs, splits that resemble tuning forks, and even circles. Their shape is accentuated by the smaller, very regular ripples between […]
May 24, 2012
A piece of Mars: Is it the latest in patterns for ties, or is it Mars? (Can it be both?) These are some unusually regular dunes on Mars, separated by a bouldered surface. The dunes have interesting pale bands common […]