Book

Observations of a Rapidly Pulsating Radio Source (1968, Nature paper)

by Antony Hewish

Summary

This 1968 *Nature* paper by Antony Hewish reports the discovery of a rapidly pulsating radio source, later identified as a pulsar. The central finding is the detection of a celestial object emitting regular radio pulses at intervals of about 1.33 seconds, with extreme precision—far more stable than any known terrestrial or solar system source. Hewish describes the observational setup, the unexpected signal, and the elimination of possible interference or instrumental artifacts. The paper establishes that the source is extraterrestrial and likely associated with a compact stellar object, such as a neutron star. A reader takes away the first concrete evidence of pulsars, a landmark in astrophysics that confirmed predictions about neutron stars and opened a new window into stellar evolution and extreme physics.

Key concepts

  • Rapidly pulsating radio sourceA celestial object emitting periodic radio pulses at intervals of roughly 1.33 seconds, discovered through radio telescope observations.
  • PulsarThe term later applied to such sources, interpreted as rapidly rotating neutron stars emitting beams of radiation.
  • Neutron starA compact stellar remnant predicted by theory, whose existence was strongly supported by the discovery of regular pulsations.
  • Radio telescopeThe instrument used to detect the faint, periodic signals from the source, ruling out terrestrial interference.
  • 1.33-second periodThe precise interval between pulses, indicating an extremely stable and rapid rotation or oscillation.

Popular questions readers ask