Look Out, Aliens!

John got home for the holidays yesterday. It is good to see him. If we don't look out, he might crash the physics club Christmas party again (Thursday at 11:30 - don't forget!).

On a totally unrelated subject, I've been thinking about aliens lately. You may be aware of the SETI (Search for Extraterrestrial Intelligence) project. On my old office computer, I had installed SETI@Home, a program which uses downtime on millions of peoples' computers across the globe to sift through radio waves from space, searching for patterns that might indicate an intentional signal among all the random noise.

So far they haven't found anything, and that almost surprises me. If a million typewriter monkeys can eventually write the works of Shakespeare, how long will it take millions of SETI computers to pick up A Midsummer Night's Dream from the outer reaches of space?

SETI has taken an interesting turn lately. It's gone active. The idea behind active SETI is that you don't just wait around for someone to say hello to you, you strike up a conversation with them. Actually, the first targeted radio message to space was sent way back in 1974. It was aimed at M13, which is 25,000 light-years away, so it will be a LONG time before we know if anyone heard us. The recent signals sent by a Russian scientist were aimed at nearby star systems, so if those systems contain intelligent life, we could conceivably hear back in some of our lifetimes. Wow!

The response of the scientific community to active SETI has not been altogether positive*. Many fear that the only aliens who could pick up and interpret a signal as weak as ours, would be aliens who are much more technologically advanced than we are. If they weren't friendly in their response to our signal, we would likely be outgunned, so to speak. However, if they were friendly, just think how much we could learn from them! Do we avoid making friends for fear that we'll be making an enemy instead?

Back to the question of why passive SETI hasn't picked up any signals from intelligent lifeforms in space: Maybe the universe is filled with scaredy-cats like the Nature editorial staff. Maybe they too are afraid to send out radio signals for fear we will be hostile, or worse yet, logical.

*_{See editorial in Nature 443, 606 (12 October 2006)}