What If There Are No Extraterrestrial Civilizations?
Remember SETI@Home? A few years ago, the distributed network that enabled analysis of radio signals using the spare resources of home computers gained quite a bit of attention. Supporters of the program claimed that we would know very soon whether there is, indeed, extraterrestrial intelligence in the universe, if only there was adequate computing power to make sense of radio waves reaching the Earth from outer space. The universe should be teaming with beings that use radio waves to communicate, they reasoned, so with some analysis of signals already being gathered by radio telescopes, it shouldn’t take long to hear from ET.
It’s been almost eight years now, and SETI@Home has listened to the entire sky visible from the Arecebo telescope it gets to piggy back space on. Still there has been no signal heard from outer space. There hasn’t even been a hopeful candidate for further examination in over two years.
So, it seems that the time has come for us to ask the question: What if there are no extraterrestrial civilizations? What if no one else in the measurable universe is communicating using radio waves of the sort we’re searching through?
There’s a lot of space out there, and a lot of planets on which alien civilizations could take route. If getting life to the point where communicates using electromagnetic devices like ours is something common, surely we ought to have detected a signal by now.
The idea posited by Star Trek of a universe teeming with advanced civilizations seems less likely than it did back in 1999. Intelligence as we know it on other planets seems more likely to be extremely rare, or not to exist at all. Perhaps the creatures on these planets are intelligent but not technological. Perhaps they aren’t intelligent at all. Perhaps even multicellular life is an oddity.
Perhaps, in spite of the presumption by scientists like Carl Sagan that we ought not to be, we on Earth really are quite special in the universe.
With every day that SETI@Home searches and finds nothing, it becomes more reasonable to assume that we may never know if other civilizations exist in the universe. We can now see planets around other stars, but they are silent planets. Whether that’s by choice or by dearth of anyone to talk is not something any telescope has the resolution to determine.
The distances to other solar systems are far too vast for us to travel without sucking a great deal of energy out of the Earth, so it makes sense to keep on listening. It does not make sense anymore, however, for our popular mythology to rest upon the presumption of aliens in spaceships with galactic empires coming by our planet to say hello.