Whether there's life on Mars could be one of the defining questions of our generation, since a definitive "yes" would suggest that life is significantly more common on places that aren't Earth, which includes the entire rest of the universe. This is why we're scouting out extremophiles, and the latest almost-alien bacteria hail from a lava tube in Oregon.
An extremophile is a form of life that lives in an environment that most other forms of life on Earth would consider utterly suicidal. Think hard radiation, high temperatures, low pH, and even ridiculous gravity (like, supernova shockwave forces). On Mars, we'd be expecting microbial life to have to be able to tolerate freezing temperatures with little or no oxygen and not much in the way of food besides rocks. Doesn't sound particularly pleasant, does it?
Pleasant sounding or not, some researchers from Oregon State University managed to find microbes living in very similar conditions deep inside a lava tube. They're in water ice (which exists on Mars), at just above freezing (slightly warmer than Mars), and in total darkness. The craziest part, though, is that these microbes make a living by eating volcanic rocks: they chow down on the iron that can be found in the mineral olivine (which we know Mars has plenty of), and we've never met bacteria that can do that before.
While this doesn't mean that there are microbes living happily in lava tubes on Mars, it does mean that we're pretty sure that there realistically could be life there. And even if there isn't life there now, this ups the odds that there may once have been life, and we ought to be able to find traces of it even now. So all we have to do is somehow convince NASA to send a giant life-huntin' robot to the surface of Mars, and maybe we'll have a shot at meeting some real live Martians. Tiny ones.
Via Daily Galaxy