And did it once rain and snow on Mars?
March 24, 2009
Mars Express Finds Rusty Evidence to Red Planet's Wet Past
Written by Ian O'Neill
The picture of Mars' wet history is gradually becoming more comprehensive. This time, new observations by the European Space Agency's Mars Express satellite have revealed concentrations of sulphates and ferric oxides in the 175 mile-wide (280 kilometres) Aram Chaos region, an ancient crater basin.
Although the true nature of these compounds remain elusive, it could reveal past atmospheric precipitation, otherwise known as rain and snow…
http://www.universetoday.com/2009/03/24/mars-express-finds-rusty-evidence-to-red-planets-wet-past/