Well, I think the most single important issue today is to make sure that nuclear weapons will not proliferate beyond the eight, or nine, countries that already have nuclear weapons; and absolutely make sure that none of these nuclear weapons or this nuclear material will fall into the hands of any extremist or terrorist group, because if they got hold of this material, they would use it. That would be the beginning of the end for civilisation as we know it.

We have all these interesting challenges now. No one knows whether automation and robotics, nanotechnology, will kill more jobs than it creates. If it does, that presents a serious problem. What are we going to do? Have a few of us work to support everybody else, or shorten the workweek for everybody? If so, how do we get from here to there? No one knows yet how we’re going to stop cyber terrorism from wrecking honest discourse in democracy and maybe putting our very lives at risk.

They have a lot of extreme physics going on inside them and scientists use them to test theories of relativity on a cosmic scale. Einstein’s theories are checking out pretty well so far.

I think most of our major challenges are not going to be in the physical field at all. I think they’re going to be in the field of human relations, of getting on with each other, of contributing. People accepting that they have to contribute something, their thoughts, their ideas, maybe even their money, towards producing a world society that is perhaps a little bit more honest and reasonable than it is now.

Certainly not. As a young child, I remember just dreaming about the Nobel Prize, but that was just a dream. It’s not something I would have ever thought was possible for me.

there are really very many. Again, as a child, it was obviously those scientists which had lived in the past that had made such an important mark in science history.

I have also benefited from teaching; as I try to explain my views to students with critical and open minds, I find myself continually being challenged to go back and rethink ideas. I now see teaching and research as complementary, mutually reinforcing activities.

At first the research did not seem to be particularly interesting – I carried out a systematic search for processes that might destroy the CFCs in the lower atmosphere, but nothing appeared to affect them. We knew, however, that they would eventually drift to sufficiently high altitudes to be destroyed by solar radiation. The question was not only what destroys them, but more importantly, what the consequences are.

It’s easy to try to exaggerate the problems just to get more attention. So for me, it was very clear that the best way to deal with that was to do the best science that I was capable of doing.

So achievement, to me, is something that just comes with this attitude of doing your work the best you can in a passionate way. It’s not something that you have to expect. It’s something that’s a consequence of what you do, but it’s certainly important.