Jocelyn Bell, woman of steel

Three Nobel Prizes have now been awarded for pulsars, but none has gone to the woman who discovered them.

Chance favours the prepared mind. But it also favours the person who works twice as hard as everyone else because of a severe dose of impostor syndrome. At least, it did in the case of Jocelyn Bell. Fifty-five years ago, she discovered “pulsars”, which are the relics of stellar explosions that pack the mass of the Sun into the volume of Mount Everest and spin at up to 716 times per second.

Bell, now Dame Jocelyn Bell, is famous for being overlooked for the Nobel Prize for Physics, which went to her supervisor Anthony Hewish. She is also one of the rare scientists to have their discovery on a bank note: the Bank of Ulster £50 note. But her road to fame was a rocky one.

Born in Lurgan, a town in Northern Ireland, Bell had an interest in science, partly because her architect father had designed the Armagh Observatory. But girls at her school were expected to study domestic science only. Thankfully, her parents kicked up an almighty fuss and the policy was changed. It might have been expected that things would be better at the University of Glasgow. But for Bell, the only physics undergraduate in her year, entering a lecture theatre was not unlike walking past a building site, with the male students stamping their feet and wolf-whistling.

Radio astronomy appealed to Bell because she did not like doing astronomy at night. While at Glasgow, she had a summer job at the Jodrell Bank Radio Observatory near Manchester. It might have led to research towards a PhD had the observatory’s director Sir Bernard Lovell not taken against women. Resigned to going to Australia, an important centre of radio astronomy, she applied to Cambridge on the off-chance. To her amazement, she was accepted.

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Cambridge was a daunting place. Not only was Bell a woman in a male environment but she was doubly disadvantaged by coming from provincial Northern Ireland. Convinced that she been admitted because of a bureaucratic mistake, she worked long and hard in the hope it would extend the period before she was, inevitably, “found out” by the university.

For two years, she helped build a very strange radio telescope at Lord’s Bridge, west of Cambridge. The brainchild of Hewish, it covered the area of 57 tennis courts and consisted of vertical wooden poles connected together by 120 miles of cable like myriad washing lines. It was designed to look for the recently discovered, and totally mysterious, “quasars”. However, on 28 November 1967 Bell spotted something very unexpected.

The output of the telescope was recorded by a pen on a rotating cylinder of paper. It was in the course of examining this that Bell noticed a “quarter inch smudge”. Magnifying it, she was amazed to see a signal peaking every 1.3 seconds, regular as clockwork. Hewish pooh-poohed it as almost certainly being man-made radio interference. But Bell, like a dog with a bone, refused to drop the matter. Used to examining 100 feet of pen recorder trace a day, she set herself the task of re-examining three miles of chart, recorded over the previous six months.

Her persistence was rewarded. She found a second source. Eventually she would find four. Given it was unlikely there were several similar man-made sources in different parts of the sky, she had proved Hewish wrong.

The first source, for obvious reasons, had been dubbed LGM-1, for “Little Green Man - 1”. But it was astronomer Fred Hoyle who guessed that it was a “neutron star”, the super-dense relic left after a star had blown itself apart in a “supernova”. Like a spinning ice skater who pulls in her arms, the core of a star would spin ever faster as it shrank down to create a tiny neutron star. Although too faint to be seen in normal circumstances, some neutron stars sweep a lighthouse beam of radio waves across the sky as they spin, making them detectable as pulsars.

Hewish, who died at the end of 2021, won the 1974 Nobel Prize, partly for the discovery of pulsars. And although three Nobel Prizes have now been awarded for pulsars, none has gone to Bell. Hewish once said that, when Columbus discovered the Americas, credit did not go to the first person who spotted land. But Bell was more than an inconsequential scientific deckhand. Having connected up every last cable of the Cambridge telescope, she knew the instrument far better than anyone else. And without her steely determination, born of all the adversity she had faced, the discovery of pulsars would not have been made at that time.

Marcus Chown is the author of many books on science. His most recent is “Breakthrough” (Faber & Faber, 2021)

This piece is from the New Humanist winter 2022 edition. Subscribe here.

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