The VLT telescope filmed a star dance around a black hole. The object moved as predicted by Einstein’s general theory of relativity, but its orbit was in the form of a socket, not an ellipse, as Newton’s theory of gravity predicts. This is stated in the work of scientists from the Max Planck Institute, published in the journal Astronomy & Astrophysics.
Using VLT, the researchers observed the black hole Sagittarius A*, which is located in the center of the Milky Way at a distance of 26 thousand light-years and is surrounded by a hot radio-emitting gas cloud with a diameter of about 1.8 pc. Astronomers suggest that its mass is 4.3 million solar masses, and its radius is not more than 45 a. e.
Unlike many supermassive black holes, Sagittarius A * is in a kind of hibernation and does not absorb matter. Due to this, it does not emit energy and red-hot matter – jets, therefore it is practically invisible to conventional telescopes. This is what allowed several tens of stars and large clouds of gas to exist, which formed in the immediate vicinity of Sagittarius A*.
In the new work, astronomers followed the S2 star, which moves around a black hole at a distance of less than 20 billion km – this makes it one of the closest stars to the object.
S2 does not rotate in a circular orbit, but processes – this means that the location of its point closest to the supermassive black hole changes with each rotation. Thus, when moving, it forms the shape of a socket.
“Einstein’s general theory of relativity predicts that the coupled orbits of one object around another are not closed, as in Newtonian gravity, but precess in the plane of motion. This famous effect, first seen in the orbit of the planet Mercury around the Sun, was the first evidence in favor of General Relativity. One hundred years later, we found the same effect in the motion of a star orbiting Sagittarius A * in the center of the Milky Way. This observation also confirms that Sagittarius A * is a supermassive black hole with a mass that is 4 million times larger than the solar one”.
Reinhard Hansel, lead author of the study