Gallery | My Favorite Planet Pics | The Moon
I know, the Moon's not a planet, but it's big and close and cool, and I love this picture. It shows the rim of the crater Erlanger, located almost at the Moon's north pole at a latitude of 87°. From that location the Sun is perpetually on the horizon, so the crater floor is never illuminated. The rim, however, sticks out above the rest of the surface, and can be lit up by the low Sun.
The crater is about 10 km (6 miles) across, and is a candidate location for ice frozen under the surface. Scientists have recently discovered that the Moon has quite a bit of water ice trapped under the surface dust, and places like Erlanger -- which never see the warming rays of the Sun, even after billions of years -- may have huge reservoirs of water eternally frozen at their bottoms. This would make Erlanger a good place to have a lunar base: water is abundant, and solar cells along the rim would deliver power 24 hours a day -- sorry, I mean 655 hours a lunar day.
Related post: Lunar Boreal Halo
Credit: NASA/GSFC/Arizona State University
