In the latest science news, a planet has been discovered which could potentially support life. A neighborly 20.3 light years away, Gliese 581g has liquid water and enough gravity to maintain an atmosphere -- making it a fairly good imitation of earth.
Great news, right? Homo sapiens now has the potential to spread across the galaxy, leaving the barren rock of Terra behind as we forge into the great empty unknown. Unfortunately, the actual "getting there" part is still a ways off. Even worse, this discovery may not bode well for the future of humanity.
What could be so ominous about discovering a distant, earth-like planet? It all boils down to the Fermi paradox. From Wikipedia, the Fermi paradox "is the apparent contradiction between high estimates of the probability of the existence of extraterrestrial civilizations and the lack of evidence for, or contact with, such civilizations." In other words, if they're out there, why haven't we seen them yet? Given the extremely long lifespan of the universe and the enormous number of galaxies and stars, the laws of probability would indicate that any space-faring life form should have colonized the entire universe by now.
The lack of evidence for extra-terrestrial life, in spite of the enormous opportunity for its growth, requires some serious explaining. One possible cause - the lack of earth-like planets which could support life - has just been ruled out completely. What reasons are left to account for the apparent barrenness of the universe?
A recent paper by Nick Bostrom of Oxford University postulates that some 'Great Filter' might exist, which causes lifeforms to go extinct before they can spread across the cosmos. This could be a cataclysmic event, or just a mundane limitation that stops most organisms from evolving into something complicated enough for space travel. Bostrom argues that this filter is either behind us - humanity has passed the test - or somewhere in our future - bad news. His conclusion: discovering evidence of a complex extra-terrestrial lifeform would indicate the Great Filter is waiting for us ahead, and we are as dead certain to fail at perpetuating our species as the billions of other races that must have existed throughout the galaxy before us.
The discovery of Gliese 581g is a great step in astronomy, physics, and potential science fiction topics. However, the Fermi paradox implies that if we ever go there, and discover even so much as an amoeba, it's a dismal sign for humanity's ultimate prospects of survival.