Quasars (short for quasi-stellar objects) are incredibly bright and energetic active galactic nuclei (AGN) powered by supermassive black holes at the centers of distant galaxies. As matter spirals into the black hole’s accretion disk, it heats up and emits enormous amounts of radiation across the electromagnetic spectrum—especially in visible light, ultraviolet, and X-rays.
Despite being located billions of light-years away, quasars are so luminous that they can outshine their entire host galaxy. This intense brightness makes them visible even from the early universe, providing valuable insights into galaxy formation and evolution.
Key features of quasars include:
- Extremely high luminosity, sometimes thousands of times brighter than the Milky Way
- Redshifts, indicating they are among the most distant and ancient objects we can observe
- Jets and winds, blasting material across intergalactic space
Quasars serve as cosmic lighthouses, helping astronomers study the early universe, map the large-scale structure of the cosmos, and understand the behavior of matter under extreme gravitational and energetic conditions.