After five decades since Stephen Hawking framed his theory on the area of the ‘event horizon’ of a black hole, a group of scientists confirm it.
Five scientists from the Massachusetts Institute of Technology and elsewhere, lead by Maximiliano Isi, found evidence to a 1971 theory of Hawking which says that the area of the event horizon of a black hole will never shrink. The study appeared in the ‘Physical Review of Letters’ on July 1.
The area of an event horizon is the limit of a black hole, beyond which nothing can escape. In other words, if an object reaches the horizon area of a black hole, it cannot go back. To elaborate, an object needs to possess a speed that can overcome the gravitational pull of the black hole to escape from it.
Within the horizon area, that speed has to be more than the speed of the light. Now, according to the Special Theory of Relativity of Albert Einstein, no object can travel faster than light. So, if an object reaches the horizon area, it cannot escape from the black hole.
Black holes remained a mystery to scientists for a long time primarily due to this effect. No light comes out of a black hole. Hence we don’t see anything.
If two black holes merge, Hawking’s theory says, the area of the event horizon of the new black hole will be the sum of the horizon areas of both the black holes. The researchers confirm this theory with 95 percent confidence.
The researchers observed gravitational waves- another discovery of Einstein in his General Theory of Relativity- to derive this conclusion. They analysed the gravitational waves of collision of two black holes. This data was collected by LIGO in 2015, which is also the first observation of a gravitational wave. LIGO is an exclusive observatory made to study gravitational waves.
The researchers took a fresh look at the data to arrive at this conclusion.
According to Isi, this research is only the beginning of many to come, reports MIT blog.
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