What does blazar mean?
A blazar is one of the most energetic objects known to astronomy: the bright, compact core of a galaxy powered by a supermassive black hole that is actively devouring matter. What sets a blazar apart from other such objects, known collectively as active galactic nuclei, is orientation — one of the twin jets of high-energy particles blasting from the black hole happens to point almost directly at the Earth. Because we are looking down the barrel of this cosmic beam, a blazar appears extraordinarily luminous and can brighten or fade dramatically over hours or days. The word was coined in 1978 by astronomer Edward Spiegel, blending the idea of a blazing object with the class of quasi-stellar sources. Blazars are important laboratories for studying relativity, particle acceleration, and the behavior of matter under extreme conditions, making them a favorite target of both ground-based telescopes and space-based gamma-ray observatories.
nounA highly variable, compact type of active galactic nucleus powered by a supermassive black hole, in which one of the relativistic jets of plasma happens to point almost directly toward the Earth, making the object appear exceptionally bright and rapidly fluctuating.
- An astronomy term for an active galactic nucleus whose relativistic jet points toward the observer, characterized by rapid variability and strong polarization across the electromagnetic spectrum.
"Astronomers detected an unprecedented gamma-ray flare from a distant blazar billions of light-years away."
"The blazar's brightness doubled within a single night, puzzling observers at the observatory."
"Data from the space telescope confirmed that the source was a blazar rather than an ordinary quasar."
Standard plural; used freely in scientific writing when discussing multiple objects of this class.
"Surveys have identified hundreds of blazars at cosmological distances."
When a galaxy aims its black-hole-powered jet straight at you, it becomes a blazar — the most violent lighthouses in the universe.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of blazar
The term "blazar" was coined in 1978 by Columbia University astronomer Edward Spiegel, reportedly during a meal, as a blend of "blazing" and "quasar." It was introduced to describe a group of highly variable extragalactic objects — including BL Lacertae objects and optically violently variable quasars — that share the defining property of a jet pointed toward the observer. The name thus carries a double echo: of "blaze," suggesting intense radiance, and of "quasar," the broader class from which these objects were distinguished.
How blazar is actually used
"Blazar" is a specialized technical term used almost exclusively in astronomy and astrophysics; it rarely appears in general conversation. It is always a countable noun referring to a class of astronomical objects.
Easily confused with blazar
A quasar is any extremely luminous active galactic nucleus, whereas a blazar is a specific subtype viewed nearly down the axis of its jet, which makes it far more variable and polarized.