pulsar

American  

[puhl-sahr] / ˈpʌl sɑr /

noun

• pulsars
  plural

1. Astronomy. one of several hundred known celestial objects, generally believed to be rapidly rotating neutron stars, that emit pulses of radiation, especially radio waves, with a high degree of regularity.

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pulsar British  

/ ˈpʌlˌsɑː /

noun

1. any of a number of very small extremely dense objects first observed in 1967, which rotate very rapidly and emit very regular pulses of polarized radiation, esp radio waves. They are thought to be neutron stars formed following supernova explosions

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pulsar Scientific  

/ pŭl′sär′ /

1. A rapidly spinning neutron star that emits radiation, usually radio waves, in narrow beams focused by the star's powerful magnetic field and streaming outward from its magnetic poles. Because the pulsar's magnetic poles do not align with the poles of its rotational axis, the beams of radiation sweep around like the beacon of a lighthouse and are thus observed on Earth as short, regular pulses, with periods anywhere between 1 millisecond and 4 seconds.

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pulsar Cultural  

1. A rapidly rotating neutron star. The radiation from such a star appears to come in a series of regular pulses (one per revolution), which explains the name.

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Other Word Forms

Noun Inflected Forms

• pulsars
  plural

Etymology

Origin of pulsar

1965–70; puls(ating st)ar, on the model of quasar

Compare meaning

How does pulsar compare to similar and commonly confused words? Explore the most common comparisons:

• quasar vs. pulsar

Explanation

A pulsar is a small, dense star that emits a beam of electromagnetic radiation in a pulsing pattern as it rotates. Like a lighthouse light, the energy from a pulsar can be observed when it's pointing toward Earth. Astronomers discovered pulsars in the 1960s, and they're still not sure exactly how they emit such huge amounts of radiation. They do know that pulsars spin, and that the "pulses" of energy have regular, precise spaces between them. Some pulsars emit radio waves, while others produce gamma ray or x-ray wavelengths. Pulsar comes from "pulse" or "pulsating star," and is modeled after quasar.

Example Sentences

See Examples For:

pulsar pulsars

His research showed that plasma around the pulsar bends and spreads electromagnetic waves through diffraction, helping form the pattern.

From Science Daily ● Mar. 28, 2026

Tracking a pulsar in this environment would allow scientists to make highly accurate measurements of space-time around a supermassive black hole.

From Science Daily ● Feb. 17, 2026

Clouds of electrons between the pulsar and Earth create patterns of brighter and dimmer signal strength across different radio frequencies.

From Science Daily ● Jan. 6, 2026

They change as the pulsar, the intervening gas, and Earth all move relative to one another.

From Science Daily ● Jan. 6, 2026

It is perhaps conceivable that a planet could survive the evolution of a star into a pulsar; or a planet could be captured at a later time.

From "Cosmos" by Carl Sagan

Its work in tracking spacecraft in the early space race, and its research into quasars, pulsars and gravitational lenses, is also part of its outstanding scientific heritage.

From BBC ● Sep. 1, 2026

Pulsar Timing Arrays rely on rapidly spinning neutron stars known as pulsars, which act as extraordinarily precise clocks in space.

From Science Daily ● Aug. 27, 2026

Most neutron stars remain hidden unless they appear as pulsars that emit radio waves or shine brightly in X-rays.

From Science Daily ● May 15, 2026

Scientists believe they are created by some of the universe's most violent events, including supernova explosions, jets from black holes, and pulsars.

From Science Daily ● May 14, 2026

They pay almost no attention to all the moons and planets, asteroids and comets, quasars and pulsars, exploding galaxies, symbiotic stars, cataclysmic variables and X-ray sources that have been discovered since Ptolemy’s time.

From "Cosmos" by Carl Sagan