Albert Einstein predicted the existence of gravitational waves in his general theory of relativity a century ago, and scientists have been attempting to detect them for last 50 years. Einstein predicted that if the gravity in an area was changed suddenly - by an huge celestial explosion, waves of gravitational energy would ripple across the Universe at high-speed, stretching and squeezing space as they travelled.
The gravitational waves were detected on September 14, 2015 by both of the Observatories. The detector in Livingston recorded the event 7 milliseconds before the detector in Hanford. Based on the observed signals, scientists estimate that the black holes for this event were about 29 and 36 times the mass of the sun, and the event took place 1.3 billion years ago. They also found that during this collision, 3 times the mass of the sun was converted into gravitational waves in a fraction of a second.
When a pair of black holes orbits around each other, they lose energy through the emission of gravitational waves, causing them to gradually approach each other over billions of years, and then much more quickly in the final minutes. During the final fraction of a second, the two black holes collide into each other at nearly one-half the speed of light and form a single more massive black hole, converting a portion of the combined black holes’ mass to energy. This energy is emitted as a final strong burst of gravitational waves.
It is these gravitational waves that LIGO has observed. This new discovery is the first observation of gravitational waves, made by measuring the tiny disturbances that the waves make in to the space and time as they pass through the earth.
At each observatory, the 2.5 mile[4-km] long L-shaped LIGO interferometer uses laser light split into two beams that travel back and forth down the arms [4 foot diameter tubes kept under a near-perfect vacuum]. The beams are used to monitor the distance between mirrors precisely positioned at the ends of the arms. According to Einstein’s theory, the distance between the mirrors will change by an infinitesimal amount when a gravitational wave passes by the detector. A change in the lengths of the arms smaller than one-ten-thousandth the diameter of a proton [10-19 meter] can be detected.
With this discovery - we humans are ready to start a new quest, the quest to explore the warped side of the universe, objects and phenomena that are made from warped space-time.
articale reference:- ligo.caltech.edu