Click to viewThough NASA has been reporting for years that there is water ice on Mars, today the US space agency held a press conference to announce definitively that the Phoenix Lander has found traces of water ice on the red planet. As Phil Plait over at Bad Astronomy points out, today's announcement was really about the continuation of the Phoenix mission, which was scheduled to sunset in the next few weeks. Now that the cool lander is scooping up hunks of ice in the sticky Martian dirt (plastered into the bottom of Phoenix's scoop, above), NASA has poured enough money into the project to keep it going at least through September. But pretty much every single news source reporting the Martian water story has neglected to tell you the most important thing about this "water ice." It's probably not drinkable.
Nobody seems to be asking the most important question: What exactly is the chemical composition of this so-called water? Partly this is because it was only yesterday that scientists got a big enough chunk of the stuff inside Phoenix's ovens, where it can melt the ice and figure out its molecular composition using a mass spectrometer. So we won't know the exact composition of Martian water for a while. But mostly calling the stuff "water ice" vagues out the truth, which is that this ice is only technically water. No creature on Earth could drink it. In fact, as planetary scientist Andrew Knoll said at the AAAS meeting earlier this year, water on Mars is probably so salty and acidic that it would be essentially poison.