Researchers at the Max Planck Institute for Gravitational Physics in Germany and the Memorial University in Newfoundland, Canada, have uncovered what happens to visible horizons when two rotating black holes merge. According to an article published in the journal Physics Review Letters, the original boundaries are disappearing and merging with other horizon-like systems. Briefly about scientific work Is said In a press release on Phys.org.
When the visible horizon coincides with the occurrence horizon of the black hole, these terms do not always describe the same thing, especially in the case of the oscillating black hole. In this case, the visible horizon is necessarily located inside the event horizon and marks the boundary, within which all light-like curves pass into the black hole. Outside the visible horizon, light can still move away from it, but it is not destined to leave the vast event horizon, which in this case is called the absolute horizon. A complete horizon can arise in the absence of a black hole, for example, the cosmic phenomenon horizon in the expanding universe.
When combined, the original event borders form a large event horizon, which is illustrated by a map similar to a band. However, the picture of the connection of visible boundaries is more complex. When black holes are close to each other, a new visible horizon immediately forms around them. However, the final rule of the original boundaries is unknown.
The method used by scientists to conduct the analysis has three main components. First, the researchers used high-precision techniques to model space-time, including the space-time inside the black hole. Second, they used a number system that allowed them to identify individual horizon-like structures even in the most distorted cases. Third, scientists have simplified complex equations that describe surfaces to equations that describe curves. This made it easier to find new boundaries to fit the curves and reset them to the full surface. All of this helped the researchers to model the horizon-like structure inside the newly created black hole.
The results of complex numerical simulations show that the two initial boundaries are short on the common visible horizon. However, they become unstable and gradually disintegrate when in contact with a large number of horizon-like structures called MOTS (slightly outer engraved surfaces). Overall, scientists have learned to distinguish unstable MOTS from fixed MOTS, which are the true boundaries of the black hole.