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My Century Home Page
Broadcast
on Wednesday 18th August 1999
JOCELYN
BELL-BURNELL
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.
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