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Astronomy: the complicated dance of two black holes deciphered

For the first time, scientists have succeeded in predicting the timing of a dance that two black holes will perform around each other with particular precision. This is what a team led by Lankeswar Dey from the Tata Institute of Fundamental Research in Mumbai, India, now reports in the specialist magazine “Astrophysical Journal Letters”.

The researchers' study, which among other things also provides new information about the physical properties of black holes, deals with two gigantic black holes in the distant galaxy OJ 287. The larger of the two has about 18 billion times the mass of the sun, the smaller it still brings it to 150 million solar masses. The smaller black hole orbits the larger one and breaks twice in twelve years through the enormous disk of gas and dust that surrounds the larger hole. This creates an extremely bright flash of light, next to which the luminosity of the entire galaxy fades.

The orbit of the smaller black hole is, however, irregular: With each orbit it is inclined and changed - among other things by the enormous gravitational field of its larger partner - so that it resembles a rosette. Accordingly, it happens through the gas disk at extremely irregular intervals within the twelve-year cycle: Sometimes there is only one year between the lightning bolts, sometimes even ten.