Answer – Quasars are highly luminous objects present at the centers of galaxies very far from the solar system.
Explanation:
The term ‘quasar’ is an abbreviation for ‘quasi-stellar radio source’. However, this name is a misnomer. Upon first being observed, they were assumed to be stars. More recently, it has been determined that quasars are not stars, but in fact active nuclei of galaxies located at incredibly vast distances from the Earth. They are not classed as AGN (active galactic nuclei).
Quasars are the brightest objects in the universe. Their high luminosity is the effect of supermassive black holes. These black holes are several times larger and denser than the Sun, and exert a gravitational pull on particles and gases around them in a manner that produces an accretion disk. The substances in this disk move at speeds that are close to that of light, thus making quasars luminous.
The radiation (part of which is light) that reaches us from quasars has traveled over several billions of light years. It originated when these far away galaxies were young, but are now ancient. Therefore, it is an important source of information for those studying the history of the universe.
