quasar

American  

[kwey-zahr, -zer, -sahr, -ser] / ˈkweɪ zɑr, -zər, -sɑr, -sər /

noun

Astronomy.

quasars plural

1. one of over a thousand known extragalactic objects, starlike in appearance and having spectra with characteristically large redshifts, that are thought to be the most distant and most luminous objects in the universe.

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quasar British  

/ ˈkweɪzɑː, -sɑː /

noun

1. any of a class of extragalactic objects that emit an immense amount of energy in the form of light, infrared radiation, etc, from a compact source. They are extremely distant and their energy generation is thought to involve a supermassive black hole located in the centre of a galaxy

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quasar Scientific  

/ kwā′zär′ /

1. Short for quasi-stellar radio source. A compact, starlike celestial body with a power output greater than our entire galaxy. Believed to be the oldest and most distant objects ever detected, quasars are billions of light-years from Earth and moving away from us at nearly 80 percent of the speed of light. For this reason, quasars are highly important to astronomers' understanding of the early universe. Little is currently understood about the nature of quasars; one theory suggests that they are produced by giant black holes destroying enormous amounts of matter, causing the subsequent ejection of radiation along their north and south poles. Many astronomers believe that quasars represent an early stage in the evolution of galaxies such as our own.

2. See also blazar Seyfert galaxy

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Other Word Forms

Noun Inflected Forms

• quasars
  plural

Etymology

Origin of quasar

1960–65; quas(i-stell)ar, in quasi-stellar radio source, the first type of quasar discovered

Compare meaning

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

• quasar vs. pulsar

Explanation

A quasar is a starlike object in space that may emit energy, light, and radio waves. In the vastness of the universe, there are many bodies such as planets, moons, asteroids, and suns. Another type of object is the quasar. Quasars are a lot like suns, though much smaller. Quasars have large redshifts, which means the light from the quasar increases in frequency, moving to the red part of the light spectrum. Quasars are powerful and usually produce a lot of radiation. Don't mess with a quasar!

Example Sentences

See Examples For:

quasar quasars

Researchers recently examined the second oldest quasar in the new collection in greater detail.

From Science Daily ● Jul. 9, 2026

"Black holes are known to 'eat' a lot of stuff, but during the active eating process and in their luminous quasar form, they also emit very strong radiation," said Zhu.

From Science Daily ● Mar. 30, 2026

The relationship between super-Eddington growth and jet-driven feedback is still not well understood, and this quasar provides a valuable reference point for testing new ideas.

From Science Daily ● Jan. 24, 2026

Although quasar activity peaked in the early Universe, quasars were rare and spread apart by hundreds of millions of light years.

From Space Scoop ● Jul. 4, 2025

Some remarkable process must be responsible for the vast outpouring of energy in a quasar.

From "Cosmos" by Carl Sagan

Meanwhile, the Atacama Large Millimeter Array will study the dust, gas, and star formation inside the galaxies hosting these ancient quasars, providing an even clearer picture of how the earliest massive galaxies evolved.

From Science Daily ● Jul. 9, 2026

It took more than a decade to discover roughly the first 10 quasars with redshifts of 7 or higher.

From Science Daily ● Jul. 9, 2026

Through the University of California's observing access, Keck confirmed two thirds of the newly discovered quasars, including the three most distant examples.

From Science Daily ● Jul. 9, 2026

For decades, astronomers have searched for the universe's earliest quasars because they preserve valuable information about how the first galaxies and supermassive black holes came into existence.

From Science Daily ● Jul. 9, 2026

Billions of light- years away are still more tumultuous objects, the quasars, which may be the colossal explosions of young galaxies, the mightiest events in the history of the universe since the Big Bang itself.

From "Cosmos" by Carl Sagan