The First Photograph of a Quasar (1963)
This is a historic photograph taken in 1963 of the first quasar ever discovered. Quasars are extremely distant and luminous objects that are believed to be powered by supermassive black holes at the center of galaxies. This photograph was taken by the Palomar Observatory in California and was the
A quasar is an extremely luminous active galactic nucleus (AGN). It is sometimes known as a quasi-stellar object, abbreviated QSO. The emission from an AGN is powered by accretion onto a supermassive black hole with a mass ranging from millions to tens of billions of solar masses, surrounded by a gaseous accretion disc. Gas in the disc falling towards the black hole heats up and releases energy in the form of electromagnetic radiation. The radiant energy of quasars is enormous; the most powerful quasars have luminosities thousands of times greater than that of a galaxy such as the Milky Way. Quasars are usually categorized as a subclass of the more general category of AGN. The redshifts of quasars are of cosmological origin.