Why we're on our own in the universe

Why we're on our own in the universe

"The process which led to the creation of humankind on Earth was a fluke - and it is highly unlikely it has been repeated anywhere else in the universe. That is the view of English physicist Professor Brian Cox, who made the assertion in an episode of BBC's Human Universe.

Meanwhile, NASA has offered a more widely accepted prediction; that one hundred million worlds in our galaxy are capable and fit to host alien life."

Those two viewpoints are not contradictory. NASA is talking about life in general. Cox is talking about technological life. The existence of life does not necessarily lead to technological life, and we simply do not know how to calculate the probability that one will lead to the other. The development of large mammals on our plant WAS a fluke caused by a global cataclysm that destroyed the large predators who ruled the planet for more than a 100 million years and developed no technology in all that time. If they had not been extinguished by that cosmic extinction event, they would still be running the show, and our planet would still presumably be free of technology.

Perhaps NASA is correct that 100 million worlds are capable of sustaining life. In fact the number may be 100 times that, and perhaps a large percentage of those bodies do harbor living plants or animals. But because we do not know "X," the probability that life will become technological life, we could be alone in the universe, as Cox speculates, if "X" is something like one in a trillion.

Because of the vastness of the universe, I think it is unlikely that we are the only technological civilization within it, but I also think it is very likely that such civilizations are few and far between, and that very same vastness probably means that the few intelligent civilizations in the universe will never encounter each other (unless the human grasp of physics is simply too primitive to understand how to conquer the light-speed barrier).