Gravitational Waves

Physicists from the Laser Interferometer Gravitational Wave Observatory (LIGO) have announced the discovery of gravitational waves, a phenomenon predicted by Albert Einstein about 100 years ago in 1916. He proposed that the Universe is made up of a spacetime fabric that gets depressed due to the moving matter, similar to a trampoline that gets bumped if an iron ball is put on it.

In this case, the scientists had recorded the ripples of two black holes colliding against each other at a distance of 1.3 billion light years away from the earth, somewhere beyond the Large Magellanic Cloud in the southern hemisphere sky. Both the black holes, one measuring 36 times as much mass as the sun and the other measuring about 29 times, were at a distance of 100 km from each other. As the two black holes neared to a point–of–no–return-touch, there was an instant violent clash and zillions and zillions of kilograms of the matter redistributed themselves in a fraction of a second. The collision led to the prelude of a new larger black hole. It converted three times the mass of the sun into gravitational wave energy. The energy that transpired in the collision was ten times more powerful than the combined power of every star and galaxy in the observable Universe. The collision was recorded in September 2015 and the spectacular discovery was announced on 11^th February, 2016. The detection of gravitational waves shows that there are plenty of black holes in the universe, the collision of which leads to the formation of new black holes.

This groundbreaking discovery was facilitated by splitting a laser beam between two mirrors which were kept 4 km apart. A slightest displacement of the mirrors caused by a passing gravitational wave is measured through a change in the interference pattern. LIGO detectors, being the most sensitive devices on earth, recorded the ripples of the collision, which was a matter of just 20 milliseconds.