What is a quasar?

A quasar, which stands for "quasi-stellar radio source," is indeed a distant galaxy that emits an extraordinary amount of energy. This energy output comes from the supermassive black hole located at the center of the galaxy, which actively accretes gas and dust, producing immense radiation across various wavelengths, including radio, optical, and X-ray. Quasars are among the most luminous objects in the universe, and their light travels billions of light-years to reach us, allowing astronomers to study the early universe and its formation.

Additionally, quasars serve as important markers for understanding the structure and evolution of the cosmos. When observing these objects, astronomers can gather insights into the behavior of galaxies and the matter surrounding supermassive black holes. Their redshift allows scientists to measure how fast they are moving away from us, providing key evidence that supports the expansion of the universe.