“There are 200 billion stars in our galaxy and at least half of them probably have planets,” ponders Dr Seth Shostack, chief astronomer at Seti, the Search for Extraterrestrial Intelligence.”How many planets in a system? Well we’ve got eight in ours, so let’s say five.”All right, that’s a half a trillion, 500 billion planets out there; and keep in mind there are a hundred million other galaxies,” he relates.”So to think ‘hey, look man, this is the only place where there’s anything interesting happening’; I mean you’ve gotta be really audacious to take that point of view.”

Stick that in your Drake Equation and, err, compute it.

Interestingly, these numbers are so massive my — insofar as I previously knew — non-believer Fiancee told me that her religious teachings state that extra-terrestrial life exists and that it was a perfectly rational belief to hold… and no, she isn’t a Scientologist.

Full article at BBC News here. The quote is from the most recent Horizon episode, UK readers can watch it on iPlayer here.