Always fueled by a supermassive black hole, each quasar emits an energy which is equal to ten to a hundred times the total energy output of our galaxy.
Outshining the very galaxy that hosts them, quasars are distant objects fuelled by supermassive black holes, which are a billion times as massive as our Sun. No wonder that they are one of the most luminous stellar bodies inhabiting our universe.
It’s been only half a century that they have been discovered by Karl Jansky, a physicist with Bell Telephone Laboratories, in the 1930s. He pinned the interference on transatlantic phone lines to the Milky Way. Then, by the 50s when astronomers were using radio telescopes to identify cosmic signals, some smaller point-source objects were constantly throwing them a curveball. Because these sign radiated from a singular source like a star, they termed it quasi-stellar radio sources or ‘quasars’. Incidentally, only one in ten quasars happen to emit radio waves, as per National Astronomical Observatory, Japan.
Thought to be formed in regions in space where there are above-average large-scale densities of matter, studies indicate that they are created when the speed of these particles get accelerated at velocities nearing the speed of light.
Though nothing can escape from black holes, they can leak around the edges. Dust and gas falling into the black hole get caught up in the accelerated particles escaping from the black hole to continuously jet above and below it.
They glow about ten to a hundred times brighter than our Milky Way, emitting millions, billions, or even trillions of electron volts. That energy is hundreds or even thousands of times the entire energy output of our galaxy, with all of its stars put together.
To exemplify, if a quasar 3 C 273, which is 2.5 billion light-years from Earth, were to come within 30 light-years from Earth, it would appear as bright as our Sun, which is only 147.1 million km away. Incidentally, 3 C 273, the first quasar to be identified is also one of the closest ones.
There are now more than two thousand known quasars and most of them, located billions of light-years away, existed during the early formation of a galaxy. A young quasar like J1342+0928, which appeared only 690 million years after the Big Bang, can reveal information about how galaxies evolved over time. Further, the scientists can identify these light sources, the closer they can be to the information pertaining to the birth of our universe.
