Why in News ?

Billions of years ago a collision between two black holes sent gravitational waves rippling through the universe. tHIS Black Holes Merged Puzzling Scientist. In 2019, signals from these waves were detected at the gravitational wave observatory LIGO (United States) and the detector Virgo (Italy).

What is a black hole ?

A black hole is a region having gravity pull is so much. Matter has been squeezed into a tiny space which increases the gravity. This compression can take place at the end of a star’s life. Event the black holes do not allow lights to leave and so it cant be visible.

Space telescopes with special instruments can help find black holes. They can observe the behaviour of material and stars that are very close to black holes.

What is a Gravitational waves ?

• Invisible ripples that form when a star explodes in a supernova, When two big stars orbit each other and when two black holes merge.
• Travelling at the speed of light, gravitational waves squeeze and stretch anything in their path.
• Gravitational waves were proposed by Albert Einstein in his General Theory of Relativity.
• In 2015, however, that the first gravitational wave was actually detected  by LIGO.
• There have been a number of subsequent detections of gravitational waves.

What Puzzling Scientist ?

• Subsequent analysis suggested that GW190521 had most likely been generated by a merger of two black holes.
• The signal likely represented the instant that the two merged and lasted less than one-tenth of a second.
• It was calculated to have come from roughly 17 billion light years away, and from a time when the universe was about half its age.
  • The mass of one of the parent black holes, which defies traditional knowledge of how black holes are formed.
  • Based on the traditional knowledge, stars that could give birth to black holes between 65 and 120 solar masses do not do so stars in this range blow themselves apart when they die, without collapsing into a black hole.
  • Merger leading to the GW190521 signal, the larger black hole was of 85 solar masses —well within this unexpected range.
  • It is the first “intermediate mass” black hole ever observed.
  • The two merged to create a new black hole of about 142 solar masses.
  • Energy equivalent to eight solar masses was released in the form of gravitational waves, leading to the strongest ever wave detected by scientists so far.
• Reason for Unusual Mass
  • 85-solar-mass black hole was not the product of a collapsing star but was itself the result of a previous merger.
  • Formed by a collision between two black holes, it is likely that the new black hole then merged with the 66-solar-mass black hole.

Source : Indian Express

Topic

Prelims : Black hole, Gravitational waves, Laser Interferometer Gravitational-Wave Observatory 

GS III : Awareness in the fields of IT, Space, Computers, robotics, nano-technology, bio-technology and issues relating to intellectual property rights

Current Affairs Compilation : 7 September 2020