Activity on Mars

I've been surprised that none of the astro-geo blogs I follow have posted this... The Big Picture has a terrific set of 35 Mars landscape images today. It's easy to think of Mars as a dead planet, and historically it has been been described as such. It is very likely (though not certainly) tectonically inactive- i.e. there is most likely no recent volcanism, and the crust is not mobile, as is that of Earth. Nevertheless, there are numerous processes that cause change to the planet's surface: wind, mass movement (for example, the landslide down the cliff face, above), sublimation of CO2 and H2O moving masses of those substances from pole to pole over Mars' year (about 2 Earth years), and the occasional meteorite impact. With few exceptions, the images depict change, however small, in relatively recent time- keep in mind, to a geologist, "relatively recent" may mean thousands to a few million years.

I think one thing that really struck me was how wonderfully abstract and "organic" some of the landscapes appear. And that these beautiful forms actually exist.