Origins
The word 'pulsar' was coined in 1968 by the British science journalist Anthony Michaelis, writing in the Daily Telegraph, as a portmanteau of 'puls(ating st)ar.' The word was immediately adopted by the astronomical community and the public, replacing the more cumbersome designation 'pulsating radio source.' The verbal root is Latin 'pulsare' (to beat, to strike repeatedly, to knock), the frequentative form of 'pellere' (to push, to drive, to strike), from PIE *pel- (to push, to drive). A pulsar is, in its name, a star that beats — a cosmic drum.
The PIE root *pel- is one of the most productive roots for verbs of motion and force in the Indo-European languages. Latin 'pellere' alone generated an enormous family: 'pulse' (from 'pulsus,' a beating — used for the heartbeat detected at the wrist), 'impulse' (a pushing into), 'compel' (to push together, to force), 'expel' (to push out), 'repel' (to push back), 'propel' (to push forward), 'appeal' (to push toward, to call upon), and 'dispel' (to push apart, to scatter). Each derivative preserves the core sense of directed force — pushing, driving, striking.
The discovery of the first pulsar is one of the most dramatic stories in twentieth-century science. In November 1967, Jocelyn Bell Burnell, a graduate student at Cambridge University working under Antony Hewish, detected a peculiar signal in the radio telescope data: a series of pulses arriving with extraordinary regularity, once every 1.337 seconds. The precision was so exact that an artificial origin seemed possible, and Bell Burnell informally labeled the signal 'LGM-1' — Little Green Men 1. The discovery of a second, then a third pulsating source at different positions in the sky ruled out an alien civilization and pointed instead to a natural phenomenon.
Development
The physical explanation was quickly supplied by the theoretical physicist Thomas Gold, who proposed that pulsars are rapidly rotating neutron stars — the ultra-dense remnants of massive stars that have undergone supernova explosions. A neutron star packs roughly 1.4 solar masses into a sphere only 20 kilometers in diameter, producing matter so dense that a teaspoon would weigh several billion tons. As the neutron star spins (up to hundreds of times per second), beams of electromagnetic radiation sweep across the sky like a lighthouse beam. When one of these beams happens to point toward Earth during each rotation, we detect a 'pulse' — hence, a pulsar.
The word 'pulsar' has entered general vocabulary as a synonym for anything that emits regular, rhythmic signals. But the astronomical pulsar's regularity is genuinely extraordinary: some millisecond pulsars are more precise timekeepers than the best atomic clocks on Earth. This stability makes pulsars useful as cosmic clocks, and the timing of pulsar signals has been used to detect gravitational waves, to test general relativity, and to establish a galactic positioning system that could, in principle, allow spacecraft to navigate by pulsar signals alone.
The controversy surrounding the 1974 Nobel Prize in Physics — awarded to Antony Hewish and Martin Ryle for the discovery of pulsars, but not to Jocelyn Bell Burnell, who actually found the first signal — has become one of the most discussed cases of gender bias in the history of science. Bell Burnell herself has been characteristically gracious about the omission, noting that Nobel Prizes are not typically awarded to graduate students. Nevertheless, her exclusion has been widely criticized, and she has received numerous other honors, including the Special Breakthrough Prize in Fundamental Physics in 2018 (which she donated in its entirety to fund physics scholarships for underrepresented groups).
Latin Roots
The family of '-ar' astronomical coinages — pulsar, quasar (quasi-stellar), magnetar (magnetic star) — reflects a mid-twentieth-century naming convention in which newly discovered celestial objects were given compact, punchy names suitable for headlines and casual conversation. These words lack classical pedigree but possess a modernist efficiency: they compress complex descriptions into two syllables and communicate immediately. 'Pulsar' — a star that pulses — is perhaps the most elegant of the set, its etymology as transparent as the phenomenon it names.