In a historic announcement, scientists said Thursday they have for the first time directly detected the existence of gravitational waves, which were predicted 100 years ago by Albert Einstein's theory of general relativity, one of the two pillars of modern physics. David Reitze, executive director of the U.S.-based Laser Interferometer Gravitational-Wave Observatory (LIGO) announced the exciting news at a press conference in Washington, D.C. The astronomer also gave a simpler explanation on gravitational waves using ripples on the pond as a metaphor. "Gravitational waves, sort of at a fundamental level, are very similar to that. In this case, the rock, is some big massive object, some accelerating object, and the surface of the pond is the space. It's basically a space. So when a big object moves and accelerates, you have two objects, orbiting around one another, it's creating these ripples that travel outward, and that's what a gravitational wave is. It's like ripples on a pond, but the ripples in this case are in space themselves," said Reitze. The gravitational waves were detected on Sept. 14, 2015, at 5:51 a.m. Eastern Daylight Time (9:51 a.m. Greenwich Mean Time) by both of the twin LIGO detectors, located in Livingston, Louisiana; and Hanford, Washington State. Based on the observed signals, LIGO scientists estimated that the black holes for the event were about 29 and 36 times the mass of the sun, and it took place 1.3 billion years ago. One scientist said the discovery may prove it is possible that a binary black hole could exist. "It's a tremendously important discovery. It's something that tells us something we didn't already know, which is in this case that it's possible to have a binary black hole. We never knew that before. We know from previous work that neutron stars, which turn into pulsars, can be binary, that they can be in pairs. We never knew for sure that they would be stars that could turn into black holes in pairs and then merge together to form this coalescing black hole and make this huge burst of gravitational energy to come out. So this is a spectacular new result for astronomy. This is not just a technological accomplishment in a word, and it's not just confirming that Einstein was right. This is saying that we now know something that we didn't already know about astronomy. It's spectacular," said John Mather, a senior scientist at the National Aeronautics and Space Administration. On Thursday, the Hebrew University of Jerusalem held a news conference to unveil documents related to Einstein's gravitational waves theory. Professor Barak Kol, head of Physics Studies at the Hebrew University, said that this event was a partial closing for a journey that started over a century ago. "This is a very exciting day for me and for many of the people involved in this quest. This is an ending or partial closing for a journey that started over a 100 years ago. And an event like this doesn't happen every day in our lives as scientists. This is a project that where thousands of human years were invested in and now finally this goal presumably was reached and will take us now to a new era," he said. Einstein's archives became a part of the university's library in January 2008.
Credit:Reuters
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.
Scientists detect gravitational waves, as Einstein predicted
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 • Hebrew University unveils documents related to Einstein's waves theory.
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