Ian, Muswell Hill in London asked:
How does SETI get around the problem of radio noise? How do you make sure that your signals arenít contaminated by all the stuff weíre splurging out here on Earth?
Well in fact, our signals are contaminated and that's why, at the SETI Institute, using the Allen Telescope Array, we do our signal processing in near real-time and we keep very good databases of all of the signals that we found and have seen recently. And we do a lot of comparison, a lot of reclassification, and then if we think itís something we havenít seen before, we actually immediately go back and look again. And we look on source, we look off source while the signal is likely to still be persistent, we chase it down.