Take a Look at the Lawman Beating Up the Wrong Guy

We're finding out more and more about Mars. Who knows--Dan Quayle might've been right a couple of President Bushes ago when he talked about water flowing through the canals. In its year-end roundup, Astrobiology Magazine named this story from December about water apparently having flowed on Mars within the last seven years as its story of the year. Now, at a meeting of the American Astronomical Society in Seattle, it's being theorized that we've already encountered Martian life-forms but didn't recognize it. Unfortunately, the downside of not recognizing life is that it's easy to kill it unintentionally, and that may have happened, as well.

Dirk Schulze-Makuch of Washington State University and Joop Houtkooper of Justus Liebig University in Germany have theorized that scientists looking for water-based life could easily overlook life based on hydrogen peroxide. Hydrogen peroxide has a lower freezing point, so it would make sense if it existed in the frigid environment of Mars. Bacteria and microbes that exist on hydrogen peroxide have been found in extreme environments such as undersea volcanoes on Earth, so there's no reason to think that they couldn't also exist on other planets, as well.

But how do we jump from there to the assumption that Earth exploration killed such Martian microbes? Tom Paulson, science reporter at the Seattle Post-Intelligencer explains:

A previously confusing finding on Mars by the Viking Landers was evidence of chemical oxidation. Scientists at the time assumed this meant the Martian surface was a highly reactive place, but further missions to Mars failed to find any evidence of oxidative chemistry.

Schulze-Makuch and Houtkooper suggest that the hydrogen peroxide detected by Viking could have come from killing Martian microbes that, like some peculiar creatures on Earth, use hydrogen peroxide the same way humans use water.

The Mars landers did all their chemical analyses by mixing samples with water -- a step that would have prompted a powerful chemical reaction in any microbe full of hydrogen peroxide, killing it and releasing the peroxide.

"Something had to oxidize for Viking to get those results," Schulze-Makuch said. Since nothing in Mars' soil or atmosphere appears capable of causing such a reaction, he said it's reasonable to suggest that it could have been a Martian microbe.

Armed with this information, the next mission to Mars can expand the parameters of what it's looking for to find out if there's any substance to this theory. The universe is large enough and we know little enough about it that there's no reason to expect that every possible form of life must be based on water.