NEW DELHI: Attributed as century’s biggest scientific discovery, scientists have detected gravitational waves or ripples in the fabric of spacetime - nearly 100 years after Albert Einstein predicted the existence of gravitational waves. This is expected to offer a remarkable opportunity to see the universe from a new perspective and opportunity to observe dark side of cosmos.
Laser Interferometer Gravitational-wave Observatory (LIGO) Scientific Collaboration is a group of more than 1000 scientists worldwide, including India, who have joined together in the search for gravitational waves.
“We have detected gravitational waves. We did it," announced a beaming David Reitze, a physicist and LIGO executive director amidst cheers from his colleagues.
The scientists announced two major breakthroughs involving key predictions of Einstein's theory -- the first direct detection of gravitational waves and the first observation of the collision and merger of a pair of black holes. This will provide scientists with something like a time-machine to look back almost to the time of the Big Bang 13.7 billion years ago when the super-heated universe began to cool down to form the first atoms.
This event, producing the gravitational-wave signal, took place in a distant galaxy more than one billion light years from the Earth. It was observed on September 14, 2015 by the two detectors of the LIGO, arguably the most sensitive scientific instruments ever constructed.
Reitze said that the discovery would allow world to hear universe and for the first time a binary black hole system has been directly observed.
"Today, we open a new window on gravitational wave astronomy. Up until now, we have been deaf to the universe. Today, we are able to hear it through gravitational waves for the first time," he said.
Gravitational waves are ripples in space-time produced by some of the most violent events in the cosmos, such as the collisions and mergers of massive compact stars. Their existence was predicted by Einstein in 1916, when he showed that accelerating massive objects would shake space-time so much that waves of distorted space would radiate from the source.
"The total power output in gravitational waves was 50 times greater than all the stars in the universe combined. Over the next decade, we will have four windows on the gravitational universe. We expect surprises," says Kip Thorne, LIGO co-founder.
LIGO, a system of two identical detectors carefully constructed to detect incredibly tiny vibrations from passing gravitational waves, was conceived and built by MIT and Caltech researchers, funded by the National Science Foundation.
According to scientist, the first direct detection of gravitational waves and the first observation of a binary black hole merger are remarkable achievements, but they represent only the first page of an exciting new chapter in astronomy.
“The next decade will see further improvements to the Advanced LIGO detectors and extension of the global detector network to include Advanced Virgo in Italy, KAGRA in Japan, and a possible third LIGO detector in India,” they said.
This enhanced global network is expected to significantly improve ability of scientists to locate the positions of gravitational-wave sources on the sky and estimate more accurately their physical properties.