Astronomers have also verified the famous "no-hair theorem".
Astrophysicists firstly accurately measured the speed of rotation of the black hole, watching the flashes of OJ287 in the constellation of Cancer. This is stated in an article in the Astrophysical Journal Letters.
The black hole OJ287 is unusual – it has been periodically "explored", and its brightness has increased several times.
Scientists found out that OJ287 dwells in the center of its galaxy and it is not alone, being in the company of another black hole.
OJ287 approaches its neighbor about every 12 years, and it passes through its accretion disk "donut", which consists of the fragments of asteroids, stellar matter, and gas.
Observing these outbreaks, astronomer Mauri Valtonen of Turku University, Finland, and his team calculated the exact mass of black holes – 18 billion suns for OJ287 and 100 million suns for its stealth companion.
In addition, they determined that the axis of rotation of the black hole could vary for the different sides to incredible 38 degrees.
Observations showed that OJ287 rotates slowly – its speed of rotation is 31.3 percent of the maximum possible value, allowed by Einstein's general theory of relativity.
It is interesting for scientists to define the exact rotation speed of OJ287, because it will help test the famous "no-hair theorem" in the next 10 years.
Previously, scientists have found that supermassive black holes at the center of galaxies do not grow indefinitely, and after reaching the mass of 50 billion Suns, their accretion disk falls apart, and they no longer absorb the matter.