Quasars

Definition

Quasars are extremely luminous active galactic nuclei powered by supermassive black holes at their centers. They emit massive amounts of energy, often outshining entire galaxies.

5 Must Know Facts For Your Next Test

1. Quasars were first identified as quasi-stellar radio sources due to their star-like appearance and strong radio emissions.
2. They are among the most distant and oldest observable objects in the universe, providing insights into early cosmic evolution.
3. The energy output of a quasar can be 1000 times greater than that of the Milky Way galaxy.
4. Quasars exhibit redshifted spectra indicating they are moving away from Earth, supporting the expansion of the universe theory.
5. Supermassive black holes at the center of quasars can have masses ranging from millions to billions of times that of our Sun.

Review Questions

• What powers the incredible luminosity observed in quasars?
• How do quasars provide information about the early universe?
• What evidence supports that quasars are extremely distant objects?

Related terms

Active Galactic Nuclei (AGN): The central region of a galaxy that is extremely bright due to energetic processes involving a supermassive black hole.

Redshift: A phenomenon where light from an object is shifted toward longer wavelengths, indicating that the object is moving away from the observer.

Supermassive Black Hole: A type of black hole with a mass ranging from millions to billions of solar masses, typically found at the center of galaxies.