17 December 2007

Planet Finder

Geoff Marcy gives a great show as a lecturer on the discovery of planets outside our solar system (extrasolar planets). He presented it on 14 Dec 2007 at Goddard Space Flight Center's Science Colloquium. This was a special colloquium in celebration of the life of John Bahcall, one of the pioneering supporters of the Hubble Space Telescope. Marcy had a bona fide letter from Bahcall, encouraging his astronomical studies. Pretty neat!

Marcy presented many of the nitty gritty details that have been learned about over 200 extrasolar planets and nearly put me and a number of others to sleep, though a few were fascinated by every nuance. Then he got down to business, which he labeled as "speculations". That's fair, but he did attempt to make an inference from what is now a statistically meaningful collection of nearby stars that have planets. Even if one is as generous as can be, there is no way that any of the planets we have found could have life on them. And that sets a limit on how many worlds could be populated in our galaxy, or any other. Given the number of stars in our galaxy, the bottom line is that intelligent civilizations, if they exist anywhere in our galaxy, must be short lived phenomena, just a few million years at most. If that is the case, we have already reached what is apparently the typical lifetime of such civilizations. We have reached the point where they die out. And Marcy's take away lesson was that the supreme challenge faced by humanity is simply to survive for longer than the typical civilization does, assuming that they exist at all outside our solar system.

Or are we happy to have a short fling with the universe, on the way to our eventual demise? For myself, I prefer to aspire to Todd Brennan's challenge: "A truly intelligent species will outlive its home star." What about you?

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