A Martian Crater Torn in Half

Sometimes geologists have it easy. In astronomy, you can have two stars right next to each other, maybe even born in the same cluster, but you can't be sure they're the same age, or which one is older than the other. Differences can be really subtle, and have to be teased out of the data. Geologists, on the other hand, get stuff like this: WOW. That is a scene on Mars, taken by the wonderful HiRISE camera on the Mars Reconnaissance Orbiter. Its shows a small portion of Ganges Chasma, a huge, spr...