It’s time to add Mercury to the list of worlds where we can go ice-skating! Yesterday a NASA spacecraft spotted vast deposits of water ice on Mercury, the planet closest to the sun, where temperatures can reach 800 degrees Fahrenheit (427 degrees Celsius). Oddly enough, around the north pole, in areas permanently shielded from the sun’s heat, NASA’s Messenger spacecraft found a mix of frozen water and organic materials. Maybe there are little micro-organisms ice-skating on Mercury!
But seriously, the find is so exciting that NASA will direct Messenger’s observation toward that area in the coming months — when the angle of the sun allows — to get a better look at the area. Researchers also think that the south pole has ice, but Messenger’s orbit has not yet allowed them to obtain measurements of that region.
Messenger will spiral closer to the planet in 2014 and 2015 as it runs out of fuel and it’s orbit is degraded by the sun’s and Mercury’s gravity. Happily, this will let researchers peer closer at the water ice as they figure out how much is there.
Speculation about water ice on Mercury dates back more than 20 years.
In 1991, Earth-bound astronomers fired radar signals to Mercury and received results showing there could be ice at both poles. This was reinforced by 1999 measurements using the more powerful Arecibo Observatory microwave beam in Puerto Rico.
Back in 1991 radar pictures beamed back to New Mexico’s Very Large Array showed white areas that researchers suspected was water ice.

A closer view, however, required a spacecraft. Messenger settled into Mercury’s orbit in March 2011, after a few flybys. Almost immediately, NASA used a laser altimeter to probe the poles. And there it was. Little microbes on ice-skates!
Image: NASA/UCLA/JHUAPL/Carnegie Institution of Washington