Quasar (noun, “KWAY-sar”)
This word describes the distant and superbright center of some galaxies.
Galaxies, like our own Milky Way, are huge collections of stars. All known galaxies that are bigger than a certain size have supermassive black holes near their center. Supermassive black holes are the most massive of black holes. These objects have a powerful gravitational pull. Quasars can be found at the cores of galaxies where one of these giants is sloppily slurping up matter. As the supermassive black hole sucks in mass, gas and dust swirl around it. This matter moves so quickly that it gives off a lot of energy.
Some of this energy is given off as radio waves. That’s why these objects were first called “quasi-stellar radio sources,” or quasars for short. But quasars emit all types of radiation, including X-rays and visible light. A quasar’s light outshines all the other stars in its galaxy. In fact, quasars are some of the brightest objects known. They can be trillions of times brighter than the sun.
Most quasars that astronomers and others have found are billions of light-years away from Earth. Because quasars are so far way, people need telescopes to see them.
In a sentence
Inside a distant quasar, two black holes may smash together in about a million years.