WASHINGTON (AFP) – International teams of researchers announced Thursday the first direct detection of gravitational waves, a major breakthrough for physics that opens a new window to universe and its mysteries.
“This step marks the birth of an entirely new domain of astrophysics, comparable to when Galileo first pointed his telescope to the sky” in the seventeenth century, France Cordova said director the US National Science Foundation (NSF), which funded the laboratory Ligo.
The discovery, which crowns efforts of decades, confirms a prediction made by Albert Einstein in his general theory of relativity in 1915.
These gravitational waves were detected in the United States last September 14 by the instruments of the observatory Ligo (Observatory Laser Interferometer Gravitational Wave, for its acronym in English), each measuring four kilometers away. The discovery was made in collaboration with European research teams, especially researchers from the French National Center for Scientific Research (CNRS), the Virgo team.
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“This new look at the celestial vastness will deepen our understanding of the cosmos and lead to unexpected discoveries “Cordova said.
Gravitational waves are produced by disturbances in the fabric of space-time by the effects of displacement of an object of great mass. These disturbances are moved at the speed of light in the form of waves and nothing stops.
This phenomenon, advanced by Einstein a century ago, is usually depicted as the deformation that occurs when a weight resting on a network. In this case, the network represents the space-time fabric.
The physical Benoit Mours, the CNRS, said that the discovery was “historic” because it allows “directly verify one of the predictions of the general theory of relativity.”
Black Holes
For this discovery, physicists have determined that gravitational waves detected in September were born in the last split second before merging two black holes, even mysterious celestial objects that result from the gravitational collapse of massive stars.
The possibility of a collision between these bodies had been predicted by Einstein, but the phenomenon had never been observed.
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According to the general theory of relativity, a pair of black holes that each orbiting the other loses energy, producing gravitational waves. It is these waves that were detected on 14 September last year.
The data analysis allowed us to determine that these two black holes merged some 1,300 million years ago. Each of them was between 29 and 36 times greater than the sun.
Comparison of the arrival times of gravitational waves the two detectors Ligo (7.1 milliseconds apart) 3,000 kilometers distant from each other and the study of the characteristics of the measured signals, detecting confirmed.
Scientists suggest that the source of the waves was probably in the southern hemisphere sky, but a greater number of detectors would have enabled a more precise location.
“Gravitational waves can be even more revolutionary than it has been the telescope, because they are different light sources,” said astrophysicist David Shoemaker, responsible for Ligo at the Massachussetts Institute of Technology ( MIT). “This discovery generates enthusiasm for physics and is very promising for astrophysics and astronomy.”
So, it will be possible to obtain signals from different bodies of large mass such as black holes and neutron stars, he said.
“The first applications we see now are for black holes, because they do not emit light and do not could see no gravitational waves,” he said, adding that so far ignored how they grow these objects, which they are at the center of almost every galaxy.
Explore the Universe
Therefore, “gravitational waves may help explain the formation of galaxies,” Shoemaker said.
“Humanity now has another tool to explore the universe,” said Tuck Stebbins, head of the Gravitational Astrophysics Laboratory at Goddard, NASA.
“Gravity is the force that controls the universe and being able to see their radiation allows us to observe the most violent and the cosmos fundamental phenomena that are otherwise unobservable,” said Stebbins.
The ability to detect these waves traveling undisturbed for millions of years becomes possible to go back to the first millisecond of so-called Big Bang.
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An indirect proof of the existence of gravitational waves was produced by the discovery in 1974 of a pulsar and a neutron star rotating one in around each other at high speed. Russell Hulse and Joseph Taylor won the Nobel Prize in Physics in 1993 for this discovery.
One of the two gravitational wave detectors LIGO project is in Livingston, in the southern state of Louisiana, and the other is at Hanford in Washington state (northwest). Both are equipped with interferometers, which measure interference and allow extremely precise waves of different types of catches.
This team works closely with the Franco-Italian team Virgo, located near Pisa, in Italy, which should be fully operational by year-end. Ligo and Virgo both have recently been equipped with modern instruments and precise measurement.
The discovery of gravitational waves is published in the journal Physical Review Letters.
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