NASA's First Pictures of Mercury Taken From Orbit

Mercury's Frozen North?

Image courtesy NASA/Johns Hopkins/Carnegie

Angled sunlight accentuates the craters of Mercury's north pole in a newly released picture from NASA's MESSENGER spacecraft. This particular section of the planet had never before been seen by scientists.

Although sunlit surface temperatures on Mercury can reach 800 degrees F (427 degrees C), at the poles Mercury has craters deep enough—that is, shady enough—to be perpetually cold.

Radar observations show that something in a few of those craters is oddly bright. One theory MESSENGER will investigate is whether the craters are filled with water ice—a very unexpected possibility for the planet closest to the sun.

(Related: "Moon Has a Hundred Times More Water Than Thought.")

Published March 30, 2011