What does pulsar mean?
A pulsar is a rapidly rotating, highly magnetized neutron star, one of the dense remnants left after a massive star explodes. Because its magnetic axis is tilted relative to its rotation axis, narrow beams of radiation sweep across space like lighthouse beams. When one of these beams crosses Earth, telescopes detect a brief, often highly regular pulse. Pulsars are therefore among the most precise natural clocks known and can help scientists test theories of gravity, study the behaviour of matter under extreme conditions, and detect changes in the timing of signals caused by other objects. The word was coined in 1967 for the puzzling periodic radio sources that were detected before their nature as rotating neutron stars was fully understood.
nounA rapidly rotating, highly magnetized neutron star that emits beams of electromagnetic radiation. Viewed from Earth, its rotation can make the pulses appear regular, like a lighthouse beam sweeping through space.
- A rapidly rotating neutron star that emits regularly repeating pulses of radio or other electromagnetic radiation.
"Astronomers detected a pulsar whose precise pulses provided an unusually stable clock for studying the passage of time in deep space."
"The pulsar continued to pulse steadily as the spacecraft approached it."
"This unusual pulsar is part of a binary system, with a neutron star orbiting another compact object."
The plural is formed by adding -s.
"The survey discovered hundreds of pulsars across the galaxy."
A pulsar is a cosmic lighthouse: its beams of radiation can cross the Earth billions of times each second, revealing a neutron star spinning with astonishing precision.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does pulsar come from?
The term pulsar was coined in 1967 from the initial expression “pulsating radio source,” analogous to “quasar” from “quasi-stellar radio source.” It was created as a shortened name for newly detected periodic radio emissions from space. Those sources were soon understood to be rapidly rotating neutron stars, with their aligned magnetic fields producing the observed pulses. The word’s meaning was therefore broadened from radio sources to related objects emitting detectable pulses at other wavelengths.
How pulsar is actually used
In astronomy, the term is used specifically for a compact object producing regular, usually periodic signals; “pulsar” should not be used as a general synonym for any blinking or pulsating light source.
Easily confused with pulsar
A pulsar is a neutron star whose rotation produces observable pulses of radiation, whereas a quasar is an extremely luminous active galactic nucleus powered by material falling into a supermassive black hole.