The latest news from the ET hunters is that there are 36 extraterrestrial civilisations in the galaxy (advanced enough to communicate). Or is it 211? Or maybe it’s between 100 and 3,000. The article I link to bandies a few numbers around.
The trouble with doing a statistical analysis of this sort of thing is we only have a sample size of one: us. We’re the only intelligent civilisation we know about (and I use the term intelligent in the loosest possible sense).
Such low numbers — and even 3,000 is low amongst 250 billion stars — would explain the Fermi Paradox, which wonders why we haven’t heard from any alien civilisations so far.
The most troubling term in the so-called Drake Equation they use to calculate these things appears to be L, which estimates how long an intelligent civilisation lasts. In fact, Drake himself thought that was they key term.
It took us 4.5 billion years to evolve and we’ve only been intelligent enough to send potentially communicative radio waves out into space for about 100 years. Again, the sample size we’re using couldn’t be any smaller.
I’m quite chuffed the proper scientists’ efforts produced a number so close to one I calculated a couple of years ago myself. I was a bit more pessimistic with my completely unscientific guesswork. I estimated there are 23 civilisations in the galaxy. I chose 420 years for that L number. I based that on someone’s study of Earth civilisations that have risen and fallen to date.
I’m sticking to the idea that alien civilisations are deliberately ignoring us because they’re fed up with the dreadful reality TV we’re broadcasting out into the cosmos. If they came here at all it would be to ask us to shut up.