Einstein was right, and sometimes twice a day. An international scientific team said Wednesday it has again detected gravitational waves, which is to date the second observation of this phenomenon predicted by the theory of general relativity Albert Einstein in 1915.
the first direct detection of gravitational waves that had been announced on 11 February a historic event after 40 years of effort that needs to better understand the mysteries of the universe.
The mystery of black holes solved soon?
This detection was carried out as the first time by the American instrument Ligo (Laser Interferometer Gravitational-Wave Observatory ), consisting of two identical detectors four kilometers long, located 3000 km from each other, Louisiana (south) and in the State of Washington (northwest).
“We know that with this second sense, the properties measured by the Ligo will allow us to begin to answer some fundamental questions in gravitational astronomy, as the mystery of the formation of black holes” welcomed Professor Sheila Rowan, head of the gravitational research Institute of the University of Glasgow, a member of the research team.
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These waves result from slight perturbations of the fabric of space-time as a result of the displacement of a massive object, like a weight deforms a net. Those seen this time were produced by the merger, there are 1.4 billion years ago, two black holes.
The analysis of data collected on December 26, it was determined that they were 14 and 8 times more massive than our Sun, a diameter less than 100 kilometers clarified these astrophysicists.
A second detection confirmed with 99.99% certainty
The two black holes of the first detection September 14, 2015 had a mass of 29 and 36 times that of the sun. Although the signal received on December 26 was lower than the first, this second detection is also confirmed with more than 99.99% certainty.
The merger of these black holes generated an equivalent amount of energy to the mass of the sun and was converted into gravitational waves, say the scientists. “With the detections of these two phenomena of strong intensity in four months for our first observation campaign, we can start to make predictions about the possible frequency detection of gravitational waves in the future,” said Albert Lazzarini, of the California Institute of Technology (Caltech), deputy director of Ligo.
“The Ligo gives us a new approach to observe some of the phenomena of the most obscure but also the most violent in the world,” he added. Besides black holes, he also cited neutron stars, the densest objects in the cosmos.
1000 mobilized American scientists
“We are starting to have an overview of astrophysics new information that can be obtained only with gravitational wave detectors “said David Shoemaker meanwhile, an astrophysicist at the Massachusetts Institute of Technology who led the Ligo modernization program.
He said the first applications are for black holes because they do not emit light and are therefore invisible without gravitational waves. “The French-Italian Virgo detector, near Pisa, Italy, is currently stopped for improvement works. It should restart late in the year and come support the US gravitational wave detectors to improve notably identifying their origins, “noted Fulvio Ricci, spokesman for the Virgo scientific team.
Ligo is also currently in the works to improve its performance. It will resume its observations in September with a sensitivity allowing it to reach 1.5 to 2 times the volume of the universe. Ligo’s team of more than 1,000 US scientists and 14 other countries, including a large contingent of French National Centre for Scientific Research (CNRS).
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