My Century Home Page

Broadcast on Wednesday 18th August 1999


I'm Jocelyn Bell-Burnell. And I'm from the Open University, where I'm in the physics department. I'm an astronomer by profession. And it was my teenage ambition to be an astronomer. But I was never quite sure I'd make it. I'm glad to say I have. And I enjoy it thoroughly.

My astronomical career had a rocket start. For when I was a student working on my thesis, I was one of the groups that accidentally discovered a totally new kind of star - an unexpected kind of star. This was in radio astronomy. And it gave out radio pulses and became known as a "pulsar". We were meant to be looking for some of the most distant things in the universe when something relatively nearby popped up. The signal was inexplicable. And we strongly suspected something was wrong with our equipment, and if it wasn't that, then it had to be locally generated radio waves - artificial interference. We could not believe it was a star. And we spent a couple of months gradually convincing ourselves that there was nothing wrong with the telescope, that it wasn't radar signals bouncing off the moon into the radio telescope's beam, that it wasn't a satellite in a funny orbit that we were picking up, that it wasn't locally-generated interference. It had to be something astronomical - and something out there beyond the sun and the planets but well within our own galaxy: the Milky Way. Our problem with those signals was that they kept a very, very regular beat - they pulsed very, very accurately - but they also pulsed very rapidly. Rapid pulses mean something small. Accurate pulses mean something big. And it was a little hard to reconcile those two. Radio astronomers are conscious that, if there are other civilisations out in space, it's probably they, the radio astronomers, that will first discover them. And so we had at the back of our minds that it might be what the British people nickname "little green men". And so we - half in jest and half-wonderingly - labelled these signals "LGM": for "little green men." But it was, a good deal of it, tongue-in-cheek. Eventually we realised that this had to be a new kind of star.

The crunch point - and for me the Eureka point - came when I found the second one. Because it was extremely unlikely that there would be two lots of little green men, on opposite sides of the universe, both signalling in an unintelligent way to an inconspicuous planet. It had to be some new kind of star. And then the question was just what. And it turns out to be a very compact form of star, a very dense form of star. A cubic centimetre of this star would weigh as much as the whole of humanity - as much as the six billion people that we believe inhabit this planet. They are literally incredible.

The discovery of pulsars - or "neutron stars", as they are sometimes known - opened up a whole new branch of physics, a whole new branch of astrophysics. And a lot of people are now working in that area with great enjoyment - and me too. It was recognised by the award of a Nobel Prize. My supervisor actually got the prize. I didn't share in it. But it was a very important occasion. It was the first time that the Physics Nobel Prize got awarded to any astronomical topic. But since that first occasion in 1974, astronomers now have quite frequently got Nobel Physics Prizes. So that's great.