The search for life....

Various colleagues have been muttering about the Fermi Paradox in recent days. I'm not sure what's brought this on, but it made me think a little more about the problem of finding life in the universe in general. Fermi's puzzler was of course to ask that if intelligent live exists in the universe then why hasn't it already shown up on our doorstep ? There are many pro and counter discussions.

I thought I'd pose a simpler question. Let's imagine that we were in possession of a master list of all star systems in the visible universe (estimated to total about 10-to-the-power-of-22), and that each system had a 1 or 0 assigned to it to indicate whether life existed in that system or not. Sounds great, somehow we've just been handed the answer to whether or not we're alone in the universe, right ? Well, the hurdle is the size of the list. This is about 11.25 million Petabytes (and a Petabyte is a million Gigabytes). How long would it take to search this list to find all the 1's - assuming there were any ?

Ten years ago the answer would have reasonably accurately been 'forever', but today we have some pretty impressive global computing power. Google, for example, processes about 24 petabytes a day at the last count. So it would take all the computing might of Google about 140 years to search our list of stars. What's so very interesting about this is that it's not a crazy number - sure it's a long time, but computing power continues to grow, and this is using just Google, add in governments, telecoms, and you could bring this down to a couple of decades.

The problem of course is where to get that list from.....