Seth Shostak, "E.T., where are you?"

Here's an excellent lecture Princeton's Seth Shostak delivered at ASU last year discussing, among other things, how long we'll have to wait until E.T. comes calling. Specifically, he mentions Carl Sagan's, Isaac Asimov's, and Frank Drake's estimates of the number of intelligent civilizations in the galaxy, 1,000,000, 670,000, and 10,000, respectively. Applying Moore's Law to SETI's listening capabilities and these estimates, we could expect to detect the first extraterrestrial civilization by 2015, 2022, or 2027, respectively. He doesn't mention this, but even pessimistically assuming that N=100 civilizations, the date of first detection would only be pushed to 2039. And if we are the only one, we should know by 2051. So within my lifetime, it is almost certain that there will be a definitive answer to this question.

Weird coincidence: I blogged about watching David Bowie's The Man who Fell to Earth just a few days ago. About nine minutes into this lecture, Dr. Shostak mentions this movie, and that Bowie made a big mistake coming to earth for water, when there are in the same solar system moons with 60-mile-deep oceans and several trillion comets. This points out one of the central flaws of many fears people have about aliens: That extraterrestrials would show up to enslave us, to eat us, or to steal some essential resources (all of our water, our atmosphere, etc.). These are all very unlikely to occur; the galaxy is filled with all of these resources in much higher abundances, more easily obtainable, in shallower gravity wells, and without several billion sentient beings protesting. And as far as enslaving or eating, we can barely hurl a few tons out of low earth orbit, and we're already on the verge of artificial meat, so it's very unlikely they'd come all this way to eat us when, if they have a taste for humans, they could easily grow their own tasty human flesh (that's the first time that phrase has appeared in this blog). And the technology to bring them all the way here would be easily able to do anything human slave labor might accomplish.

Other interesting factoids he points out: We (well, not me) are currently trying to spectroscopically detect methane in the atmospheres of extrasolar planets. Methane cannot exist for long periods in a warm oxygen atmosphere; it relatively quickly breaks down into CO2 and water. Distant civilizations should be able to detect us (well, the presence of life) by the above-equilibrium level of methane in our atmosphere. A large amount of this methane comes from the . . . posterior eructations of livestock. Thus, if we detect methane in a distant atmosphere, we may very well have discovered pigs in space.

Final interesting fact: The human brain runs on about 25 watts. That's just amazing--the most complicated structure in the known universe uses the same power as a lightbulb.