pulsar

American  

[puhl-sahr] / ˈpʌl sɑr /

noun

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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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

Example Sentences

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

When undisturbed by outside forces, the radio pulses from a pulsar reach Earth with remarkable consistency.

From Science Daily • Feb. 17, 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

Perhaps the recipients will make nothing of it, or think it is a recording of a pulsar, which in some superficial sense it resembles.

From "Cosmos" by Carl Sagan