Rest easy: SETI's Seth Shostak explains why extraterrestrials won't snatch you from your bed.
There's plenty to fret about in this world: the economic downturn, environmental degradation, or snails in the bougainvillea. Reasons for anxiety abound.Well, let me lighten your load by stating that you can strike the fear of alien abduction from your stack.This is not a trivial solace. A controversial 1992 Roper poll claimed that 2 percent of Americans were possibly victims of alien hijacking. If that percentage is true, and applies world-wide, then there are as many abductees walking the streets as there are natural blondes. What's unclear, however, is whether they have as much fun.Probably they don't. Most abduction reports involve being involuntarily hauled out of one's home or auto, followed by a short session of meddlesome experiments at the smooth-and-cool hands of a gray-skinned extraterrestrial. Frequently, the aliens play doctor, removing sperm or eggs from their victims without so much as a consent form or the slightest romantic gesture.The usual explanation for such brutish behavior is that the extraterrestrials have come to our world because of reproductive problems on their own. They want hybrid babies (for some reason). But the idea that any species would resort to interstellar travel for breeding purposes seems ludicrous. Salmon will swim a few hundred miles to spawn, but the nearest stars are a lot farther than that-tens of trillions of miles, at a minimum.In addition, I note that the salmon have the good sense to reproduce with other salmon. We can't breed with another species, despite the occasional barnyard attempt. That's true even though every living thing on this planet has the same biochemistry as you. We all share DNA, and for the more familiar life forms, quite a lot of DNA. Anything you're likely to see at the zoo has DNA that's at least 75 percent identical to your own. There's no reason to assume that the aliens have DNA at all.Breeding won't work. But there's another point: the aliens don't know we're here. Evidence for the existence of Homo sapiens-in the form of FM radio, television, and radar signals-has only been leaking off this planet for about 70 years. No aliens farther than half that number (in light-years) have had time enough to sense our presence, and rocket to Earth to snatch you from the bedroom. Just so you know, the number of star systems within 35 light-years is only about a thousand. Astronomically speaking, that's a trivial sample. It's highly unlikely that we have randy, cosmic company so close by.Then there's the lack of compelling evidence. If 2 percent of Americans are abducted, that's 7 million victims in the current generation, just in the United States. You'd expect some good, physical evidence for that, beyond stories told by the abductees.Indeed, world-wide the number of supposed alien abductees exceeds the number of Africans who were taken from their homes for the slave trade. No one doubts that the forcible abduction of slaves took place. There are the descendants of the abductees of course, but also physical evidence of the abductors. As example, in 2004 a slave ship was found in the waters off the Turks and Caicos Islands. So, given that a larger number of people seem to have been abducted by aliens, why are there no spacecraft parts to examine?People like to believe that extraterrestrials have come to Earth to probe and prod. It's flattering, after all, to think that these esoteric beings are showing some personal interest. But the evidence for alien abduction is weaker than last quarter's housing starts. Drop it from your list of torments.Guest blogger Seth Shostak is a Senior Astronomer at the SETI Institute. He is the author of Confessions of an Alien Hunter: A Scientist's Search for Extraterrestrial Intelligence, and hosts SETI's radio show Are We Alone?