Quasar Brightness

What is A quasar? A quasar (contraction of QUAsi-StellAr Radio source) is an extremely powerful and distant active galactic nucleus. Quasars were first identified as being high redshift sources of electromagnetic energy, including radio waves and visible light, that were point-like, similar to stars, rather than extended sources similar to galaxies.While there was initially some controversy over the nature of these objects — as recently as the 1980s, there was no clear consensus as to their nature — there is now a scientific consensus that a quasar is a compact region 10-10,000 Schwarzschild radii across surrounding the central supermassive black hole of a galaxy, powered by its accretion disc.[...]

Mystery Of Twin Quasar Brightness Revealed:Variations in the brightness of the Q0957+561 quasar, also known as the "twin quasar" due to its duplicated image on Earth, are intrinsic to the entity itself and not caused by the gravitational effects of possible planets or stars from a far away galaxy. This is the conclusion of a new study resolving a mystery that has intrigued astronomers for the past 30 years.[...]