On September 8, 1967, Jocelyn Bell — a twenty-four-year-old PhD student at Cambridge — noticed a repeating signal in data from the radio telescope she had spent two years helping to build. The signal was so regular, so precise, that her supervisor initially joked it might be "Little Green Men." Bell kept analyzing. By November she had identified a second source. By early 1968 she had identified four, each producing pulses of radio waves with extraordinary periodicity. She had discovered pulsars — rotating neutron stars — one of the most significant astronomical finds of the twentieth century.

Bell was born in 1943 in Belfast. She grew up adjacent to the Armagh Observatory, where her father was an architect, and developed an early and serious interest in astronomy. She enrolled at Cambridge in 1965 as a graduate student under Antony Hewish and helped construct the four-acre radio telescope required for his research project. The construction took two years. She then became responsible for analyzing the hundreds of feet of chart paper the telescope produced weekly.

The discovery of pulsars was announced in Nature in February 1968. The paper listed Hewish as first author and Bell as second. In 1974, the Nobel Prize in Physics was awarded to Hewish — and to Martin Ryle, who had led the broader radio telescope program — for the discovery of pulsars. Bell was not included.

The Nobel Committee does not explain its individual decisions. Hewish accepted the prize.

Bell has spoken about the Nobel omission with characteristic precision: she was a graduate student, she says, and graduate students make discoveries within the frameworks their supervisors build.