Far from Earth, two black holes revolve around each other, creating waves that bend time and space. Albert Einstein predicted their existence more than a century ago, describing them in the general theory of relativity.
But for the first time they were able to be noticed only in 2015 with the advent of the Gravitational-Wave Observatory of a Laser Interferometer (LIGO), for which the creators received the Nobel Prize in Physics. This discovery also led to the formation of a new field - gravitational-wave astronomy. But the mystery has spawned many questions.
For example, how did these gravitational waves appear and in what environment? Now scientists were able to demonstrate how they can look like if two black holes form inside a massive collapsing star.
Gravitational waves for the first time allowed to find black holes, but the origin of the holes still remains a mystery. One theory suggests that they are formed during the dynamic fragmentation of the dying star's inner core. As a result, two fragments should become black holes and rotate around each other in stellar remnants. To test this assumption, the researchers used a supercomputer and numerical theory of relativity tools to create a model of two black holes in the described medium.
Numerous hours of computation and comparison with LIGO scores led to interesting results. If black holes appear in a high-density environment, the merging process will be faster. If the density resembles a vacuum, then the simulated gravitational waves converge with those observed in reality.
This information not only better characterizes the dynamics of double black holes, but also confirms that the first gravitational waves obtained by LIGO came from black holes in an empty region of space.