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.

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.

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.

The mystery of summoning up words. Where are they in the mind, in the brain? They appear to be an agency from nowhere. They exist somewhere in our ground or in our air. They come from unknown darkness. From a place we normally don't think about.

Tony was cautious. He suspected I’d wired the radio telescope up wrong. So we checked on another radio telescope on the site. The thing was pulsing nicely on mine but as we stood by the pen recorder of this other telescope, nothing happened. It was a horrible moment. And suddenly there it was, five minutes later because we had miscalculated when the telescope would see it. If we’d miscalculated by 25 minutes, we’d have all gone home and the story would be different.

It looked like an agricultural frame, something you might grow peas up – a lot of wires and cables strung from posts over a space the size of 57 tennis courts. It was actually built to study radio emission from quasars. I built the prototype and then six of us took two years to build the real thing.

Occasionally there would be something I didn’t recognise and I’d record it with a question mark or, as a joke, LGM for Little Green Men. It was easier than saying “you know that funny pulsing source at right ascension 1919, declination plus 20”. So, it became LGM.

From one particular piece of the sky an unclassifiable signal sometimes recurred and my brain started to say: “You’ve seen something like this before, haven’t you? You’ve seen something like this before from this bit of the sky , haven’t you?” I got out previous recordings from that bit of sky. It often wasn’t there, but when it was, it was keeping its place amongst the stars.

My contemporaries were more upset about the Nobel than I was not to be recognised. One of them labelled it the 'No-Bell' prize! But it was fine by me. There's no Nobel Prize in astronomy and I was really proud that it was my stars that had convinced the prize committee that there was good physics in astrophysics.

I was very, very thorough, making sure I really understood how that telescope worked, and that it was working properly. I was quite convinced that I wasn't clever enough to be in Cambridge and would be thrown out at some stage. My policy was to work as hard as I could so that I'd know I'd done my best. We now label this as impostor syndrome, but we didn't recognise, and certainly didn't name it, back then.