The Crater of Eternal Darkness

The Lunar Reconnaissance Orbiter (LRO) continues to return spectacular images.  The one featured today might seem like an odd choice as it is almost totally black.

This is Erlanger Crater near the Moon’s north pole. It’s diameter is about 10km (6 miles)  Unlike Earth, the Moon’s axis is tilted only about 1.5 degrees.  Therefore, the Sun never gets more than a couple of degrees high in the sky near the poles.  If you have a crater with nice high walls, there are places where the Sun never shines.  The bottom of these craters have temperatures that hang out around -375F (or about 50 Kelvin).

Why do we care about dark spots?  In these very dark craters that do not receive Sunlight, water ice can happily sit and wait for oh, say, humans to land nearby and have a ready source of water.  Exploring crater such as this is one of the reasons we launched LRO.