Quasars are among the brightest bodies in the universe. Only supernovas and gamma-ray bursts rival them in luminosity. Quasars are fueled by supermassive black holes, which are black holes billions of times more massive than our sun. They emit great amounts of heat and light that come from these behemoths, and have jets of matter and energy that can be much larger than the galaxy that they are in. They can consume matter equivalent to a few thousand suns per year!
Giants of The Universe
Quasars are gigantic objects, but they are not infinitely “on.” The quasar can only emit waves of energy if they have a source of material to form a disc around it, otherwise known as an accretion disk. Once the disk’s matter runs out they “shut down,” leaving their galaxy to be very faint. Quasars can live to up to a billion years. In 2007, we discovered 100 thousand of these quasars. Although quasars are very bright, they cannot be seen in the night sky even with a telescope. This is because the nearest one is about 3 billion light-years. However, quasars can be detected by their emissions of enormous amounts of gas.
Like A Star
Quasar is short for “Quasi-stellar radio source,” because quasars were found when astronomers probed space with radio telescopes. Quasars are one of the most distant objects in the universe, and give astronomers details about galaxies too distant to study directly.
Photo Credit: ESO/M. Kornmesser