Phoning ET

Aliens in Hollywood movies, and in most of the alien-related sci-fi reviewed on this site, are fairly easy to find. They might be trying to eat you for instance, or at least take over the planet, or they might be enemies or allies in some great space-opera war. At worst, very shy aliens might require a package of Reese's Pieces and the faith of a child to lure them out of hiding.

But real aliens are much much harder to find. In fact they're so hard to find that they act like they don't exist at all. Confessions of an Alien Hunter by Seth Shostak, one of the leading scientists for SETI (the Search for Extraterrestrial Intelligence) presents the science behind trying to find another intelligent species out among the cosmos.

So far, Shostak admits, in its search for evidence of aliens, SETI has come up with very little, or, to be more precise, absolutely nothing. Does that mean we should give up trying? Shostak doesn't think so. He describes the search for ET as an ancient one. The ancient Greeks, for instance, believed in intelligent species on distant worlds. The dream to contact a non-human culture is one that runs deep in the species, and the implications of a successful search would be profound.

Besides, Shostak explains, hopeful as they are, SETI scientists haven't really expected to find anything just yet. By most of their figures, given the speed at which they are currently able to process data, it might take 1,000 or 10,000 or 100,000 years before they pick up a distinctly non-natural alien signal. Fortunately, as equipment improves, which it is doing quite rapidly, SETI will be able to search the heavens much more quickly and more thoroughly. If all goes well, some SETI scientists predict, we should be able to find evidence of an alien civilization by 2020. Or, by then, anyway, they'll know that some of their assumptions are wrong.

Because this calculation depends on a lot of assumptions. It assumes that life-supporting planets are not incredibly rare. It assumes that intelligent life develops on these planets fairly often. It assumes that at least some intelligent species develop the technology to broadcast radio waves (or maybe generate laser beam signals). And it assumes that at least some of these species are curious enough about life beyond their planet that they send a signal into space. And while that's a lot of assuming, the cosmos is also extremely vast, so the possibility of discovering an aliens civilization remains quite strong.

Shostak ably guides readers through all the history and math required to make SETI's case. Don't worry, it's not all that dry. Understandably a little defensive, Shostak spends significant space distinguishing the legitimate science of SETI, from the pseudoscience surrounding UFOs and alien abductions. Finally, he outlines the strategies and long range plans of SETI, and conjectures about what might happen should SETI succeed.

What drives the book forward, though, are the many heartbreaking false alarms the SETI faithful have already had to endure. You can feel the tension in the room as scientists seek confirmation that the signal they're hearing or seeing is one that is truly emanating from an alien civilization. And you feel just as strongly the disappointment when, no, it turns out to be a hoax or a just another communications satellite. It made me a fan of SETI. What they're hoping for might be the longest shot in the universe, but I think they should keep trying.