What would happen if a black holes event horizon collided with another?
If two black holes with their event horizons touching each other were to collide, they would inspiral and merge together to form a single, larger black hole [1,3]. This is because both black holes would be trying to suck the other one up [2].
There are many theories as to what would happen if two black holes collided. One theory is that the two black holes would merge into a single, larger black hole [1, 3]. This theory is supported by the fact that black holes spin at incredibly fast rates, and are often more than 100 million times as massive as our Sun [1]. Another theory is that the two black holes would recoil from one another due to their rapid rotation and energy would be released in the form of gravitational waves [1, 3]. A third theory is that the collision would create a funnel-shaped vortex above the accretion disk of the black hole, and the two black holes would eventually merge into a single black hole [2]. A fourth theory, proposed by Rovelli and his collaborators, is that the collapse of a black hole is prevented by quantum gravity effects and that the black hole could actually explode [4].