Mustan aukon tapahtumahorisontti on raja mistä kaikki suunnat vie vain ns. singulariteettia kohti ja mikään ei pääse pakenemaan. No jos 2 mustaa aukkoa kiertää toisiaan siten että tapahtumahorisontin reunat limittyy niin kumpaan aukkoon menijä putoaa jos menee tuohon yhdistettyyn tapahtumahorisonttiin? Onko menijän kannalta nyt 1 vai 2 singua jos 2 niin silloinhan toinen aukko voi kumota tämän pakenemis säännön (jos vain toiseen päätyy vaikka on kahden tapahtumahorisontin sisällä)
En viitsi/jaksa/osaa tehdä nättiä referaattia, mutta
https://phys.org/news/2021-11-apparent-horizons-binary-black-holes.html tuolla on asiaa pohdittu.
"For many years, it has been known how the event horizon looks during a merger; that's the famous pair of pants diagram, but that does not tell us much about the dynamics, especially how the spacetime evolves inside the black holes," Pook-Kolb, Hennigar and Booth explained. "To get more insight, we look instead at apparent horizons, which are ubiquitous in the numerical relativity community."
...
"The most important result of our study is that it unveiled the fate of the original two horizons," Pook-Kolb, Hennigar and Booth said. "They both eventually vanish, but they don't just disappear. Instead, they smoothly annihilate with other horizon-like structures. One might go as far as saying 'they turn around in time," and in doing so, they become what we call unstable."
A further achievement of this recent study is that it introduces a method to easily differentiate between generic marginal surfaces, also known as MOTSs, and MOTSs that can be regarded as physically meaningful black hole boundaries (i.e., horizons). In the future, this method could also be used by other research teams to study horizons in black holes.