Stockholm, Oct 3: Three American scientists from the Laser Interferometer Gravitational-Wave Observatory (LIGO) have won the Nobel Prize in Physics for their contribution to detecting gravitational waves -- ripples in the fabrics of spacetime which were predicted by Albert Einstein a hundred years ago. The scientists were awarded the Nobel prize "for decisive contributions to the LIGO detector and the observation of gravitational waves", the Royal Swedish Academy of Sciences announced here on Tuesday. The 9 million Swedish kronor (825,000 British pounds) prize was divided. One half was awarded to Rainer Weiss of Massachusetts Institute of Technology (MIT) and the other half jointly to Barry C. Barish and Kip S. Thorne -- both from California Institute of Technology (Caltech). Originally predicted in the early 20th century by Einstein, gravitational waves were not detected until 2015, when LIGO identified the first such signal from two merging black holes. "The 2017 Nobel Laureates have, with their enthusiasm and determination, each been invaluable to the success of LIGO," said the Royal Swedish Academy. "Pioneers Rainer Weiss and Kip S. Thorne, together with Barry C. Barish, the scientist and leader who brought the project to completion, ensured that four decades of effort led to gravitational waves finally being observed," the Academy added. The international LIGO Science Collaboration (LSC) consisting of about 1,000 scientists from universities and research institutes from about 15 countries, including from India, announced the first detection on February 5, 2016 and second one on June 15, 2016. "I view this more as a thing that recognises the work of about 1,000 people, a really dedicated effort that's been going on for -- I hate to tell you -- as long as 40 years," Weiss told the Royal Swedish Academy of Sciences, acknowledging the contribution of other scientists in achieving the scientific milestone. There was a very significant presence of Indian scientists in this milestone scientific achievement. There were 37 authors from nine Indian Institutions in the scientific publication presenting the first discovery of gravitational waves published in the Physical Review letters by the LIGO Scientific Collaboration and Virgo Collaboration. There were 39 authors from the same nine Indian institutions in the publication for the detection of the second black hole merger event. Currently, Indian participation in the international LIGO Science Collaboration, has over 60 researchers, constituting five of the members of the LSC, making it the fourth largest national participant. LIGO discovered its third gravitational wave on January 4, 2016. The fourth gravitational wave, observed on August 14, 2017, was made using two LIGO detectors in the US --loacated in Livingston, Louisiana, and Hanford, Washington -- and the Virgo detector in Italy. This was the first time gravitational wave emitted by a merger of two black holes was observed using three detectors -- a critical new capability that allows scientists to more closely locate a gravitational wave's birthplace in space. India is also working towards setting up its own LIGO observatory. The mammoth LIGO-India project, for detecting gravitational waves, completed a year in February. "Scientists expect to hear space-time rhythms from Indian soil within next six to seven years," according to Karan P. Jani, one of the many US-based Indian researchers working on the project. LIGO India is a joint scientific collaboration between LIGO laboratories of the California Institute of Technology (Caltech), Massachusetts Institute of Technology (MIT), the US, and three leading Indian institutions, namely, the Inter-University Centre for Astronomy and Astrophysics (IUCAA), Pune, Institute for Plasma Research (IPR), Gandhinagar, and Raja Ramanna Centre for Advanced Technology (RRCAT), Indore.