If three or more objects move around each other, history cannot be reversed. That is the conclusion of an international team of researchers based on computer simulations of three black holes orbiting each other. The researchers, led by the Dutch astronomer Tjarda Boekholt, publish their findings in the April issue of the journal Monthly Notices of the Royal Astronomical Society.
Source:
https://phys.org/news/2020-03-symmetry-laws-physics.html