There’s rarely any middle ground on the topic of life in space. You either believe the untold trillions of stars and planets out there make it anthropocentric folly to think that biology emerged nowhere else, or you believe that nope, life is particular to the nonreproducible conditions on our uniquely verdant, uniquely organic world. Either way, science agrees with you. Paul Davies, physicist and cosmologist at Arizona State University and author of the book The Eerie Silence argues that the vast number of other worlds is actually misleading, that the statistical improbability of organic molecules lining up just as they did to create life as we know it is greater than even so large a sample group could overcome. (Of course, Davies does not rule out the possibility that so-called shadow life — so very different from our own that we wouldn’t recognize it even if it sidled right up to us — could exist.) Other exobiologists, particularly those at NASA say nope, life as we know it is easy. All you need is water, an energy source, some hydrocarbons and time and you can easily cook something up—perhaps even in our own solar system on worlds like Jupiter’s watery moon Europa or in the deep, ice deposits on Mars.
PHOTOS: The Earth As Seen From Above
The debate will be settled — epochally, transformatively — only when life actually is found out there. Until it is, exobiologists will continue to look, theorists will continue to theorize, and the rest of us will continue to wonder about a question that has intrigued us from the moment our species learned what it meant to wonder at all.