Skip to content
Science

What is a quasar?

A quasar is the blazing core of a distant galaxy, powered by a supermassive black hole devouring gas. As matter spirals in, it heats up and shines brighter than entire galaxies, making quasars among the most luminous objects in the universe.

See it, don’t just read it.
Watch a 2-minute lesson with voice + animation that explains a quasar.
▶ Watch the visual lesson

Key things to understand

  • 1It's the ultra-bright center of a distant galaxy.
  • 2A supermassive black hole pulls in surrounding gas.
  • 3The in-falling matter heats up and blazes with light.
  • 4Quasars can outshine their entire host galaxy.
  • 5Because they're so far away, we see them as they were billions of years ago.

Frequently asked questions

What powers a quasar?
A supermassive black hole at a galaxy's center; gas spiraling into it heats up enormously and radiates intense light.
Why are quasars so bright?
The matter falling toward the black hole releases vast energy as heat and light, outshining all the galaxy's stars combined.
Why do quasars tell us about the early universe?
They're so distant that their light has traveled billions of years, so we see them as they were when the universe was young.

Related topics