Mars Is Even Less Hospitable Than We Thought

In the hunt for extraterrestrial life, one of the best places to look is Mars. Science fiction authors have been imagining life on Mars for generations, and scientists have been looking for signs of life on the red planet for decades. But new research suggests that life on Mars might be closer to science fiction than science after all.

Mars is not a hospitable place. It's always cold, there's almost no liquid water, and ultraviolet light constantly bombards the surface of the planet. Just based on those facts alone, the case for life, at least on anything that's currently alive, does not look good. But there's another factor that makes life on the surface of Mars next to impossible: perchlorates.

Perchlorates are chemicals often used in rocket fuels, but several of the orbiters and landers sent to Mars have spotted the chemicals occurring naturally in the Martian soil. A pair of researchers at the University of Edinburgh found that when perchlorates are exposed to ultraviolet light they kill bacteria twice as fast as UV light alone.

But it gets worse. Mars soil also contains chemicals like hydrogen peroxide and rust. When these chemicals are combined with the perchlorates and blasted with UV light, they kill bacteria 11 times faster than UV light alone.

This is bad news for any potential life on Mars. The surface chemicals and UV light make Mars an inhospitable place for any earth bacteria, which means it's likely inhospitable for any potential Mars bacteria as well.

But there's still reason to hope. The deadly Mars chemical cocktail requires ultraviolet light to kill bacteria, so there's a chance that bacteria may be able to survive a few feet beneath the surface. The European Space Agency's upcoming ExoMars rover, set to launch in 2020, has a drill capable of reaching several feet below the surface, where we might finally get some answers.