If we're looking for intelligence in the universe I think everybody assumes that this has to start with life and so the question is: "How likely is it that there will be life elsewhere in the universe?"

We know that within the solar system is very unlikely there will be anything more advanced than microbial life, but if we think outside the solar system and then, the distances are, of course, immense, then there could be Earth-like planets with more advanced form of life.

Cancer is not something confined to human beings. It's found in all multi cellular organisms where the adult cells proliferate, so it's widespread in the biosphere. It's a phenomenon that is deeply related to the history of life itself, so by studying cancer I think we can illuminate the history of life itself and vice versa.

I suppose my interest in looking for life elsewhere in the universe really dates back to my teens. What teenager doesn't look up at the sky at night and think am I alone in the universe? Well most people get over it, but I never did and though I made a career more in physics and cosmology than astrobiology I've always had a soft spot for the subject of life because it does seem so mysterious.

I think if we're going to send messages to the stars then it needs a great deal of thought that it's something that should involve the entire not only scientific community, but the entire world community. We need to think very carefully indeed.