Astronauts have been stuck in low-Earth orbit, boldly going nowhere. American attempts to kick-start a new phase of lunar exploration have stalled amid the realisation that NASA's budget is too small for the job.

When I was a student, the laws of physics were regarded as completely off limits. The job of the scientist, we were told, is to discover the laws and apply them, not inquire into their provenance.

No planet is more earth-like than Earth itself, so if life really does pop up readily in earth-like conditions, then surely it should have arisen many times right here on our home planet? And how do we know it didn't? The truth is, nobody has looked.

Should we find a second form of life right here on our doorstep, we could be confident that life is a truly cosmic phenomenon. If so, there may well be sentient beings somewhere in the galaxy wondering, as do we, if they are not alone in the universe.

I got into physics through pop science and quantum science and ended up being such a quantum groupie.

Educated guesswork’ is what science is. You form hypotheses, test them against the evidence, and if they fit the evidence, you can assume you’ve got close to the truth."

Science never gives up searching for truth, since it never claims to have achieved it. It is civilizing because it puts truth ahead of all else, including personal interests.

We slow the progress of science today for all sorts of ethical reasons. Biomedicine could advance much faster if we abolished our rules on human experimentation in clinical trials, as Nazi researchers did.