Astronomers Detect Merging Of Two Black Holes

The massive collision between two black holes created the first intermediate-mass black hole ever discovered. It has a mass of nearly 142 times that of the sun. The bang created enormous energy that was released through gravitational waves that equaled the energy of eight suns, and it took about 7 billion years to reach Earth. The gravitational waves were first detected on May 21, 2019, by the National Science Foundation’s Laser Interferometer Gravitational-wave Observatory in the US.

Experts have many questions on this phenomenon, and they still do not know how supermassive black holes are formed. The scientists are still not clear as to how the black holes grow. Some options they are considering are that the black holes grow when a star collapses or from stellar-mass black holes. The intermediate-mass black hole is in between the stellar mass and supermassive black holes. With this, there is proof about the existence of intermediate-mass black holes.

The gravitational event did not last long, and it was only for about one-tenth of a second. The waves reached Earth from 7 billion light-years away, and this is the farthest distance we know so far on Earth. Scientists are excited about the discovery, and they feel that gravitational wave observations can revolutionize the way we analyze black hole formations. In the future, it will be possible to understand how they are formed and how they grow. Astronomers have named the gravitational wave event as GW190521. The detectors picked up four little wiggles that took 7 billion years to reach EarthEarth. This is different from the first detection of such gravitational waves by LIGO in 2015. Astronomers are excited to analyze the data as they realize that this is the most massive signal that they have ever received.

There are two main types of black holes that include stellar-mass black holes and supermassive black holes. When the stars die, and they have a mass that is about a few times that of the sun, it leads to stellar black holes. On the other hand, supermassive black holes are those that can have mass in the range of hundreds or thousands of times the mass of the sun. The intermediate black hole lies in between the two, and it is formed when two massive black holes merge into each other. In the recent signal received by the detectors, it was found that the two black holes that merged had solar masses of 85 and 66. In some instances, stars may no longer have enough pressure to support the outer layers, and they may collapse beneath their own weight leading to the creation of a black hole. However, any star that collapses in this manner should not be able to produce a black hole that has a solar mass in the range of 65 to 120.

Many theories are floating about the incident, and the merging of two stars, primordial black holes created after the Big Bang, are said to be some of the reasons for this formation. Experts also believe that a hierarchical merger, when a black hole is formed from a previous merger of smaller black holes, seems a good idea. Astronomers feel that this event has thrown up more questions than answers at the moment, and they are excited to be working on this project. Researchers are also considering the option that the signal that was received only for a short duration may have a different source altogether, and it may not have come from the merging of black holes. They are also analyzing the option that the gravitational waves might have come from a collapsing star in our own galaxy. Apart from that, a cosmic string that was generated after the universe inflated could have also produced such a signal. However, the theory of two black holes colliding to create the signal seems the best logical idea at this moment.

LIGO and Virgo have been providing new insights about the cosmos since 2015. They sense gravitational waves, and this can reveal many events in space-time like the merger of black holes that cannot be seen with ordinary telescopes. Astrophysicists often estimate the size of the object from the properties of gravitational waves. The way these objects change the pitch can also help them in analyzing the size of the object. In the same manner, they also get information about other features of the objects. This study has provided direct evidence about various objects that are about 50 times the mass of the sun.  These are unconventional black holes, and LIGO researchers are also not ruling out the option that these may have existed ever since the Big Bang, and they might have formed spontaneously after the Big Bang. However, when it comes to justifying the size of the black holes, researchers are of the opinion that they became too large as they were formed from earlier mergers of black holes. In this way, the repeated mergers might have contributed to such large black holes.

As of now, researchers are not clear as to in which galaxy the merger happened. They are still going with some information to explore the facts. The LIGO and Virgo collaboration has yielded good results so far this year as they had earlier detected a forbidden mass range in June. To give a common explanation about black holes, researchers describe them as a region of space in which matter has collapsed under its own weight, and it has a huge gravitational pull that does not even allow light to escape. This can be formed when certain large stars die, and they can be thousands of times bigger than our sun. However, how they are formed at the galaxy centres is not yet known, and they are usually detected by the way they influence their nearby objects. These usually produce gravitational waves when they spiral into each other, and this is what the astronomers have detected this time to analyze that it was a big bang where two black holes collide.