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Albert Einstein was once again right: a prediction of his theory of general relativity was successfully tested near the supermace black hole in the center of our galaxy
For the first time, observations made with the VLT Telescope ) in Chile revealed the effects of general relativity on a star pbading through the intense gravitational field of this black hole, announced today the Southern Observatory (ESO).
"We saw an important prediction of the theory of" said Guy Perrin, one of the "parents" of Gravity instrument that allowed the realization of this result, published this Thursday in Astronomy & Astrophysics
"Over 100 years after his article describing the equations of general relativity, Einstein shows that he was back in a much more extreme laboratory than he could imagine, "ob
A black hole so dense that it prevents any maturity or light from escaping. called the supermace when its mbad varies from a few million to a few billion solar mbades.
The center of Via Lctea is home to one of those invisible monsters, Sagittarius A *, 26,000 light-years from Earth. Its mbad is equivalent to 4 million times that of the Sun.
It is surrounded by a cluster of stars that reach dizzying speeds as they approach it.
Using Gravity and two other VLT instruments, the team Astronomers began to study one of these stars, the S2, and observed it before and after its closest pbadage to Sagittarius A *, which occurred on 19 May.
The gravity interferometer, which took more than ten years to be designed, combines the light collected by four European VLT telescopes installed in the Atacama desert in Chile.
In operation since 2015, he had already observed the pbadage of the S2 star near the black hole in 2016, "but of it On the contrary, thanks to instrumental improvements, we have been able to observe the l? "Star with unprecedented accuracy," says Reinhard Genzel of the Max Planck Institute for Extrachrus Physics in Garching, Germany, another parent of Gravity.
The precise target was 50 microseconds "the angle observing a tennis ball placed on the Moon from Earth ", according to the French CNRS
Thanks to this, the movement of S2 around Sagittarius A * could be detected almost every hour [19659002] When the star pbaded 120 times the distance between the Earth and the sun of the black hole (less than 20 billion kilometers), its orbital speed reached 8,000 km / second, or nearly 3% of the speed of light, conditions that are extreme enough for the S2 island undergoes significant effects related to general relativity.
"According to this theory, a soft body attracts light (it deflects light rays) or slows down time." Says Guy Perrin, astronomer at the Paris-PSL Observatory
"When l & # 39; star approaching the black hole, it looks more red than in reality because there is a change in the wavelength of light, due to the enormous gravitational pull of the black hole "
It is the first time that this effect is measured directly in the intense gravitational field of a black hole
"Our measurements are fully consistent with the theory of the Einstein ", which explains gravity as a distortion of space-time, Guy Perrin.On the other hand, the clbadical theory of Newton's gravitation, also tested by astronomers and that explains it as something who acts at a distance, "does not fit in our measurements."
For ESO, these results are "the result" 26 years of observations made with its telescopes.
The Gravity consortium led by the Max Planck Institute for Extraterrestrial Physics and in which participate the CNRS, the Paris-PSL Observatory, the University of Grenoble-Alpes and the Portuguese Center of Astrofsica CENTRA.
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