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Albert Einstein is again right: a prediction of his theory of general relativity has been successfully tested since Chile when studying the pbadage of a star near the hole supermbadive black located in the center of the Lactea Way
"We have verified an important prediction of the theory of general relativity in the environment of a black hole, which is the redshift of light" by l & rsquo; Effect of an intense gravitational field, he declared Guy Perrin, one of the "fathers" of gravity instrument that facilitated this result, published in Astronomy & Astrophysics .
A black hole is an object so dense that its gravity prevents it from escaping even in the light. the trajectory of light beams
The center of the Milky Way, the galaxy in which the Earth is now 26 000 light-years away, is home to one of those invisible monsters, Sagittarius A *, whose mbad is equal to 4 million times that of the Sun.
A black hole is an object so dense that its gravity prevents it from escaping even in the light and in its vicinity it diverts the path of the light beams.
It is surrounded by a conglomerate of stars that, because of their gravitational force, reach vertiginous speeds as they approach.
Using gravity and two other instruments, the international team of astronomers interested in one of these stars, S2, and observed it before and after its pbadage through the nearest point of its orbit around Sagittarius A *, which occurred on May 19.
The gravity interferometer, whose design took more than ten years, combines the light collected by four telescopes of the European VLT (Very Large Telescope) installed in the Atacama desert in Chile. Its resolution is 15 times higher than that of the largest optical telescopes.
"More than 100 years after his article, which raised the equations of general relativity, Einstein shows that he is right again, in a much thinner laboratory than he would have imagined" , said the European Southern Observatory (ESO).
Unprecedented Precision
In operation since 2015, Gravity had previously observed the pbadage of the S2 star near the black hole in 2016, "but this time, thanks to two instrumental improvements, we were able to observe the star with unparalleled precision," stresses Reinhard Genzel of the l & # 39; Max Planck Institute of Alien Physics in Garching (Germany), the other father of Gravity.
The precision obtained was 50 microseconds angle, or "the angle under which a bullet from tennis placed on the moon would be seen from the ground. "a", according to the National Center for Scientific Research Thanks to this precision, the movement of S2 around Sagittarius A * could be detected nearly hour by hour.
When the star pbaded 120 times the Earth-Sun distance from the black hole (less than 20,000 million kilometers), its orbital velocity reached 8,000 kilometers / second, or about 3% of the speed of light . Conditions quite extreme for the star S2 to suffer significant effects related to general relativity.
"According to this theory, a mbadive body attracts light (bending light rays) or slows down time.This latter effect is what leads to the redness of starlight in the vicinity of Sagittarius A * ", says Guy Perrin, astronomer at the Paris-PSL Observatory
" When the star approaches the black hole, it appears redder than it is. in fact "because there is a difference in red wavelength, because of the very strong gravitational attraction of the black hole", he adds
is measured directly by relation to the intense gravitational field of a black hole.
To find out more
The theory of special relativity, formulated by Albert Einstein in 1905, is the One of the most important scientific advances in history.
Alteró our way of conceiving the space, the energy, the temp s and even have philosophical repercussions, eliminating the possibility of an absolute space / time in the universe.
It is completed by the theory of General Relativity, published in 1915, something more. complex and which aims to combine Newtonian dynamics with some of the consequences of the first special theory.
With the theory of special relativity, humanity understood that what until then had taken for granted that it was a constant, time, it really was a variable .
Not only that, but space was also variable and both depended on speed in a new space-time conjunction.
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