Posts Tagged ‘extraterrestrial life’
Over at the New APPS Blog, Eric Winsberg reacts to the discovery of Kepler-186f–a roughly Earth-sized planet that is in the right location around its red dwarf star to potentially be habitable–by revisiting the Fermi paradox. If there are suitable Earth-like environments where technology-using intelligences like ourselves could develop, where is everyone?
I’ve discussed this topic in the past. I remain intrigued by Keith Wiley’s 2011 paper arguing that, at this stage, we really lack the data necessary to disprove the existence of advanced civilizations. All we can say is that we don’t think that there are any megascale constructions–Dyson spheres, for instance–in our local neighbourhood and that there are no civilizations making loud broadcasts that we’ve picked up. Winberg has come up with six possibilities.
One is that there is any substantial chance at all of life arising at all on a planet with conditions more or less like ours. I admit that it is possible for this premise to be false, but I don’t begin to see how that could be. Given the hundreds of billions of stars in our galaxy alone, let alone our local cluster, the needed probability here would be so tiny.
The second is that there is no substantial chance of life in general evolving into a life form that has the intelligence and other capacities required to create technology. This also strikes me as implausible.
The third is that given enough time, such a life form would eventually be capable of colonizing a nearby planet. This one seems very likely to be true, given that such a capacity does not even seem wildly out of reach for us.
The forth is that such life forms aren’t extremely unlikely to _want_ to colonize nearby planets. Given that life forms tend to grow exponentially in number, and the fact that planets have finite resources and a finite capacity to absorb waste, this also seems like a tough one to deny.
The fifth is that some such life forms would colonize planets exponentially. That is, for example, each colonized planet would go on to colonize two more planets. Or even 1.1 more planets, on average. To make the paradox go away, one would have to deny that a single intelligent life form that had a large head start on us ever did this.
Sadly, it seems to me that the easiest premise to deny is this sixth one: intelligent life forms are never able to develop the technology, cooperative effort, etc. required to colonize a planet BEFORE they either use up all the resources, or capacity to absorb waste, of their home planet.