Dust and oddities

A piece of Mars: In the dustier regions of Mars, there are many small dark streaks on steep slopes that we don’t understand well. Because we don’t know much about them we call them “slope streaks”, which is not the most imaginative name. They are actively forming on Mars today, though, and seem to be

Wind and hills

A piece of Mars: Blueish and yellowish ripples wind their way around a bright hill. The yellowish ones are probably not moving anymore, but the blueish ones are likely still active from time to time. (HiRISE ESP_020889_1320)

One perfect barchan on Mars

A piece of Mars: In nature most dunes pile on one another or strongly influence each other. But occasionally, like a perfect flower or crystal, you find a perfectly shaped dune. Here is a crescentic dune, called a “barchan”, formed by winds moving from right to left. (HiRISE PSP_007676_1385, NASA/JPL/Univ. of Arizona)

Sand, wind, and dust

A piece of Mars: This is what dunes look like in the deepest part of Mars, where the air is full of bright dust that constantly settles out onto everything. The wind helps to clear off the sand dunes (blue in this image) in two ways: one is by dust devils that leave crooked tracks


A piece of Mars: Patterns within patterns (metapatterns?).  These small martian dunes shown an unusual complexity in their crossing lines, indicating that they were formed by winds from several directions (and it is likely that those winds changed over time). What do you think, should it be the next thing in tweed fashion after houndstooth

Wind on high

A piece of Mars: We are looking way up high on Arsia Mons, one of the tallest mountains in the Solar System (its summit is ~19 km high — Mt. Everest tops out at 8.848 km; the location of this image is at ~10 km). Up here the winds come screaming down the mountain at

New duties

Today I became the deputy manager of the Planetary Landscapes Facebook page. Looks like it will be fun, and I hope it won’t take up too much time. I do like the idea of sharing all of the beauty of the universe with people out there — that beauty is a major reason why I