For the first time, astronomers managed to observe matter rotating around a hole in a minimum orbit close to it with the help of GRAVITY Instrument. The speed of the rotating substance is about 30% of the light speed. It takes place in the center of the Milky Way, about 26 thousand light years away. The object of the study was a compact radio source in the constellation Sagittarius, known as Sagittarius A.
For many years, astronomers had believed that there is a black hole, but people cannot see it directly. There is nothing surprising in it because the black hole does not reflect and does not emit any electromagnetic radiation. But it can emit substance around them.
The GRAVITY instrument mounted on the Very Large Telescope in Chile was used for observation. The VLT is the complex of four optical telescopes. GRAVITY allows combining their data in the near-infrared range (wavelength – 0.74-2.5 microns), getting a virtual “telescope” with a mirror diameter of 130 meters.
On this miracle technology, scientists were able to register several flashes produced by a substance orbiting a black hole in its accretion disk along the most internal stable circular orbit. This is the smallest orbit in its radius at which matter can orbit around a black hole. Everything that is closer is doomed to takeover.
The observed phenomenon is consistent with the predictions of the General Theory of Relativity and is another confirmation of the existence of a black hole. Apparently, it is not the only object of this kind – in the centers of other spiral galaxies, scientists expect to see a similar picture.
Earlier this year, GRAVITY and SINFONI, another VLT tool, allowed the same team to accurately measure the parameters of the orbit of the S2 star when it passed through an extreme gravitational field near Sagittarius A. For the first time, the effects predicted by Einstein’s general relativity in such an extreme environment were revealed. During the fast passage of S2, strong infrared radiation was also observed.
