As much as humans have dreamed of spreading life to other planets, and as central as the notion may be to the survival of the human race, is it possible that both our past AND our future lies amid the stars?
I'm not talking about alien astronauts or dread vessels full of monsters descending from the heavens. As awesome as those ideas may be, reputable scientists tend toward the idea of lithopanspermia, or the transfer of simple life from one planet to another by impact-expelled rocks. When large cosmic bodies smash into each other, they expel debris. If hardy-enough bacteria were able to cling to these rocks and survive the expulsion, journey and re-entry, then they could potentially land on another habitable world.
We know of 40 or so Martian meteorites that appear to have traveled to Earth in this manner. As we continue to ponder the possibility of ancient life on Mars, it's hard not to ponder some of Earth's microbes that thrive in the harshest conditions. Might these extremophiles be the descendants of ancient asteroid hop-ons from Mars?
While scientists have performed a number of experiments using bacteria and high explosives, they've never really tested these ideas in space. Luckily, as reported this week by Discovery News, a Russian space probe is headed for the Martian moon of Phobos in October. Scientists plan to attach a canister full of 10 different species, including microbes, seeds and bacteria. If they return to Earth alive, then we'll be one step closer to understanding how life might have emerged or arrived on our planet.
However, according to an NPR story from today, there's always the outside chance that the mission will wind up infecting Phobos or Mars itself with this rugged sampler of Earth life. And then what if these hardy little critters take a liking to their new home? We're still exploring the possibilities of original microbiological life on the red planet. The last thing scientists want to do is contaminate other worlds with Earth life.
Unless the Earth life in question is human civilization, of course. That, after all, is the stuff of dreams.