Martian Skies - The Big Picture - Boston.comYesterday's announcement by NASA of the discovery of water ice on Mars by its Phoenix Lander probe made big news everywhere. The discovery involved the observation of water ice sublimating into the air - that is, the water went from solid to vapor state without reaching the liquid stage. The Martian atmosphere has perfect conditions for sublimation - extremely thin, dry and cold. How cold? Well, y
