Two black holes merged in 12.8 billion light years! Flashes lasting a few seconds alert scientists
Editor’s note:The GW190521g event has been happening for more than a year. This gravitational wave event is two 12.8 billion light years away. Black hole The merger was formed, but the flash that lasted for a few seconds made the scientists vigilant and finally found an unexpected result:there is a larger black hole behind the black hole merger that is ready to swallow them together!
Impression of the universe｜Toutiao exclusive deep science column No. 1352
On May 21, 2019, LIGO laser interferometer gravitational wave observatory and European Virgo The detector discovered the GW190521g event almost simultaneously, which was a black hole merger event that was 12.8 billion light-years away from Earth. In fact, there are not many incredible places where two black holes merge, but the GW190521g event is different. Scientists found a flash when these two black holes merged! Under normal circumstances, there is no flash when the black holes merge. When the two black holes approach each other in a spiral, they eventually collide and merge, emitting gravitational waves.
Image interpretation:In the GW190521g event, the environment of the two merged black holes is very characteristic, located near a quasar
Picture Interpretation:Imaginary picture of two black holes merging
The black hole itself has no place to produce visible light. The escape speed of the black hole surface exceeds the speed of light, and even light cannot escape the gravitational field of the black hole. So what is this strange flash? LIGO and the Virgo detector discovered the combined gravitational waves of the two black holes, and received a flare signal about 34 days later. Scientists believe that the black hole combination itself does not produce light, so the flash does not come from the two combined black holes.
One view is that when a black hole merges, the gas around the two black holes will collide, and the strong impact force generated by the merger will cause the gas to violently rub and form a flash. Gas collisions will occur days to weeks after the black holes merge and release flares. The equipment to detect the flare release comes from the transient factory of Paloma Observatory. The equipment can detect high-energy events in the universe, such as gamma bursts, neutron star merger, etc. The transient factory at Paloma Observatory is a 16-group CCD detector that scans the Milky Way twice every 24 hours to discover high-energy events in the Milky Way. In the GW190521g event, the environment of the two merged black holes is very characteristic, located near a quasar, it is not difficult to judge this is a very scary combination:one with Supermassive black holes also have two small black holes on the accretion disk of the quasar. Before the two small black holes were annexed by the supermassive black holes, the two small black holes merged first. During the merger, the surrounding gas collided violently, releasing flares in random directions, so it was observed by our earth.
Image interpretation:The process of merging black holes is like a dance of two death spirals, and eventually a black hole of greater mass will be formed
Photo Interpretation:The merging of black holes will form gravitational waves
The GW190521g event gave us a new understanding of the black hole merger. It turned out that a merger could occur before the merger and it could form flares. At the same time, supermassive black holes already existed in the early universe beyond 12.8 billion light years, and quasars also appeared in such an early universe. This shows that black hole mergers are not the main way for black holes to grow. Supermassive black holes were born in some way, not formed by the merger of black holes. The universe was born only 13.7 billion years ago, and the supermassive black holes that appeared one billion years after the universe was called the originator of the black hole world. The impression of the universe is exclusive to today’s headlines, all others are counterfeit and reprinted are illegal.