(Above) Alison Boyle of the Science Museum with Jocelyn Bell Burnell's radio telescope.
Curator's Choice: In her own words... Alison Boyle, Space Curator of the Science Museum explains the strange allure and importance of Jocelyn Bell Burnell's radio telescope, a star item in the Science Museum's new exhibition, Cosmos and Culture.
"It's one of those objects in astronomy that's very, very important but doesn't look like anything special at all. Most people would think of a radio telescope as a great big dish, but this one was nothing like that.
It was basically strings of wire across four acres of field and, to be honest, what we have on display looks like a bit of washing line – two vertical posts supporting a length of copper wire, and another post in between with a box on it.
Nevertheless, it's a small part of the apparatus used to make one of the greatest astronomical discoveries of the 20th century.
The telescope was originally designed to look for interplanetary scintillation. Faraway radio sources coming towards the Earth have to go through streams of charged particles that come out from the sun, so the radio source seems to twinkle a lot when you observe it. That's still a very good way to look for faraway radio sources – things like quasars.
In 1967, Jocelyn Bell was at Cambridge University working towards her PhD and quasars were the subject of her thesis. They were even more mysterious then than they are now; far-distant celestial masses that gave off huge amounts of energy, but about which very little was really known.
Jocelyn helped build this telescope – its official name is the Interplanetary Scintillation Array – and ultimately ended up in charge of it. She was using it to look for quasars when she stumbled upon something else entirely.
Readings from the telescope emerged on a paper chart. Jocelyn knew what the signature of a quasar should have looked like, but several months into poring over this stuff she found a mark that looked like a bit of scruff – a line caused by radio interference. As she checked through her records she found that it had happened a few times.
She and her advisor explored all the possibilities; at first they thought the cause might be man-made. There's a great piece of paper in the archives at Cambridge on which someone has written "interference from nearby tractor" next to a patch of scruff. But these marks appeared regularly, always from the same patch of sky. They had to explore space-based causes; satellites, radar bouncing off the moon, even aliens – Jocelyn jokingly referred to the object as LG-1 for a while, meaning "Little Green Men."
In fact, Jocelyn had found the first pulsar, a sort of dense, spinning neutron star that sends out radio waves. As a discovery, it's definitely up there with, say, that of the microwave background, which helped prove the big bang. It's very rare for someone to discover a new type of celestial object. Even now we actually don't know what the full impact of it is, and we probably won't know for another few decades.
When people walk into the gallery, this isn't likely to be something that causes them to stop in their tracks and say, "Wow! That’s the coolest thing I’ve ever seen!" This wasn't built to last, and it wasn't designed to be showy – it was simply built to get a job done. I also wanted to make the point that science isn't all about big discovery moments – for those to happen, many, many people have to put in a lot of hard slog behind the scenes.
Generally, when our visitors think 'telescope' they'll tend to imagine a tube someone sits at the end of and looks through. It's important for us to demonstrate that telescopes do come in all shapes and sizes, and quite often it's the most unassuming objects that don’t look impressive at all that are really important in the history of science."
Cosmos and Culture, runs at the Science Museum, London, until December 30 2010
