Astrophysicists have long grappled with the mystery of how supermassive black holes in galaxy centers merge, with the final parsec problem stumping researchers for decades. Recent observations suggest that these black holes do overcome this challenge, with dark matter potentially playing a crucial role. Some physicists propose that self-interacting dark matter could nudge the black holes closer together, while others suggest ultralight dark matter waves may facilitate the merger. Controversy exists over whether such exotic physics is necessary, with alternative explanations involving stars or gas disks also under consideration. The imminent launch of the LISA spacecraft may provide the answers needed to solve this complex astrophysical puzzle.
https://www.quantamagazine.org/how-do-merging-supermassive-black-holes-pass-the-final-parsec-20241023/