But of course, one of the fascinating issues for us as astronomers, and indeed for biologists, is to ask, “Is there life out there already?” One of the things we are doing now is understanding the likelihood of life.  And also, can we detect it?

There are some projects now to actually look for any evidence for something artificial out there.  Some artifacts, or some kind of transmission in radio or optical light, which is not natural, which is either something beeping away or some very narrow band signal which can’t be explained naturally.  Because if we could find any evidence for something which was artificial like that, that would be a huge discovery because it would show that concepts of logic and physics weren’t limited to the hardware in human skulls but had emerged somewhere else.  Of course, what is out there, it may not be anything like us. It could be some machine made by some long-dead civilization, which is beeping away or malfunctioning in some way.

I think, even if we detect something which is artificial, it’s most unlikely it’s a message and aimed for us, et cetera, as some science-fiction stories say.  But nonetheless, if we could find anything manifestly artificial out in the cosmos, that would tell us that the cosmos is even more interesting than we think it is because complex evolution would have happened somewhere else.  So that’s why I’m extremely in favor of using all the techniques we now have to look for evidence for something artificial out there, as well as, of course, trying to understand the natural environments, not just on Earth but in the cosmos.