If two galaxies collide, the merger of their central black holes triggers gravitational waves that propagate through space. A team of researchers has calculated that this happens around 10 million years after the meltdown – much faster than previously assumed.
In his General Theory of Relativity, Albert Einstein predicted gravitational waves over a century ago. This year they were detected directly for the very first time, oscillations were recorded, caused by the merger of two huge black holes. But research into gravitational waves – and thus the origin of the universe – continues: in 2034, three satellites will be sent into space by the European Space Agency to measure gravitational waves at even lower frequency ranges. .
Until now, it was difficult to predict with certainty the precise moment when gravitational waves are triggered before they propagate through space. An international team of astrophysicists from the University of Zurich, the University of Heidelberg and the Chinese Academy of Sciences announces that they have done so, using extensive simulation.
Every galaxy has a supermassive black hole at its core, which can be millions or even billions of solar masses. In a realistic simulation of the universe, the merger of two galaxies about 3 billion years old and relatively close to each other has been simulated. With the help of supercomputers, they then calculated the time necessary for these two central black holes of about 100 million solar masses to emit strong gravitational waves, after having entered into collision. And the result is surprising.
In the process, each supercomputer was tasked with calculating a certain phase of the orbital convergence of the two massive black holes and their parent galaxies. Compared to previous models, the relationship between the orbits of central black holes and the realistic structure of galaxies has also been taken into account. A year of research later, researchers claim that the first gravitational waves would have been triggered after 10 million years – around 100 times faster than previously assumed.
Source: University of Zurich