Friday, November 9, 2012

Is SETI Silly?

No, I don't think it's silly.  It remains entirely possible that simply by carefully studying the photons flying at Planet Earth from all directions, we will find clear evidence of an extraterrestrial civilization.  However, as I have taken pains to point out, we really don't know what we're talking about when we use that phrase, so we're going to have quite a long (and I think, healthy) debate about that the evidence should be, and how best to find it.

The Search for Extraterrestrial Intelligence (SETI) is a loose affiliation of scientific institutions funded by private donations, trying to find a way to search for other technological species in our galaxy.  It's just one galaxy - doesn't sound too ambitious - but where to start?

Scientific investigation requires starting with what we know, and then making the smartest testable guesses we can about something we're less sure about.  Any other approach is almost sure to fail.  So, what do we know?  We know that radio wavelengths can find their way through the dust and gas in our galaxy, and that they are relatively simple and cheap to generate.  We think we know (could be wrong, but the arguments see solid), that it isn't possible to transmit information faster than the speed of light, which is what radio waves can do for you.  So, if we're looking for interstellar communications, looking at the radio photons makes sense - based upon what we know.

Of course, what we don't know is likely much vaster.  If we search and search among the radio photons and find nothing, that is a valuable datum, but we are not yet done with that search.  We need to cover more of the electromagnetic spectrum over the entire sky, and search for such transient phenomena as Benford Beacons.

Now any aliens out there probably don't know we have radios and are looking for them, so transmitting to us would be for them a shot in the dark, and I doubt they would do it constantly enough for us to pick them up at a random time.  We have to cover the sky in the time domain as well, and SETI simply doesn't have the resources to do that exhaustively now.  However, the volume of space in which our inadvertent radio transmissions could be detected expands by about 3-4 cubic light years every day, so the odds keep getting better of of a transmission specifically directed to Earth, although they are still small.  Someday a radio source may light up and stay lit that will be unambiguously artificial, and then everything will change.

So, I support SETI, and hope you will throw a few bucks of your own in the direction of the SETI Institute from time to time, so heroic people like Jill Tarter can keep searching.

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