Quasars
Shining from 10 to 100,000 times brighter than the Milky Way, quasars are highly luminous celestial bodies powered by supermassive black holes at the center of galaxies. Despite being relatively small (about the size of our solar system), quasars emit light brighter than the sum of all the stars in their host galaxy. However, did you know that quasars are about 20 billion light years away from us? Because quasars are far away, we see these objects as they were when our universe was young; we do not see them as they are in the presence. This phenomenon allows us to study the evolution of the universe.
Quasars are essentially the light-producing structures that surround the black hole. Visible and ultraviolet light from the quasar shines at x-ray energies, while even hotter gas above the quasar shines at x-ray energies. Along the black hole’s poles, quasars’ jets emit energies of millions, billions, and even trillions of electron volts. This energy exceeds the total light of all the stars within a galaxy, making quasars the brightest objects in the universe.
Even with all of the excitement surrounding the wonder of quasars, studying them proved difficult. After its discovery in the early 1960s, astronomers realized that naming them did not help determine what these objects were and what purpose they served. One of the biggest challenges they faced was that it was virtually impossible to comprehend the amounts of energy generated by the black hole engines at the hearts of quasars. While it is difficult to accept, astronomers have learned that quasars are just one example of an animal in the cosmic zoo about which one must accept the facts rather than try to comprehend them.