The 100-year old prediction of Albert Einstein about existence of spacetime ripples- gravitational waves-has finally been confirmed by a group of scientists working with LIGO, the Laser Interferometer Gravitational-Wave Observatory.
The twin LIGO detectors, located in Livingston, Louisiana, and Hanford, Washington, USA both discovered ripples in the fabric of spacetime “arriving at the Earth from a cataclysmic event in the distant universe.”
The discovery besides confirming the nature of black holes gives astronomers a new tool for observing the cosmos.
Dave Reitze,the LIGO executive director,said the waves were the result of the collision of two black holes that occurred 1.3 billion years ago.
A LIGO news release states: “Physicists have concluded that the detected gravitational waves were produced during the final fraction of a second of the merger of two black holes to produce a single, more massive spinning black hole. This collision of two black holes had been predicted but never observed.”
The scientists, based on the observed signals, 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.
“According to general relativity, a pair of black holes orbiting around each other 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, according to Einstein’s formula E=mc2. This energy is emitted as a final strong burst of gravitational waves. It is these gravitational waves that LIGO has observed”, the news release further reads.
Reitze said observation of gravitational waves accomplished an ambitious goal set out over 5 decades ago to directly detect this elusive phenomenon and better understand the universe, and, fittingly, fulfilled Einstein’s legacy on the 100th anniversary of his general theory of relativity.