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.

---

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

---

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

---

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

The researchers are now aiming to discover the first known quasar beyond a redshift of 8, which would reveal an object that existed within the universe's first 630 million years.

From Science Daily ● Jul. 9, 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

Instead, this quasar remains bright in X-rays and strongly radio-loud at the same time.

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

Perhaps a quasar standard candle will be found, and the distances to the quasars determined independent of their red shifts.

From "Cosmos" by Carl Sagan

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

According to Hennawi, advanced algorithms can now examine tens of millions of astronomical sources and separate the few genuine quasars from the overwhelming number of lookalike stars and galaxies.

From Science Daily ● Jul. 9, 2026

Until now, astronomers had mostly detected only the brightest and rarest ancient quasars, leaving too few examples to study the early quasar population as a whole.

From Science Daily ● Jul. 9, 2026

The two oldest have redshifts of 7.69 and 7.77, making them the earliest quasars ever identified.

From Science Daily ● Jul. 9, 2026

There were clusters of freckles on her forearms and wrists, an entire Milky Way spreading across her forehead, even a few sputtering quasars flung into the wormholes of her ears.

From "Middlesex: A Novel" by Jeffrey Eugenides