This simulation shows a black hole simulation. Its magnetic field lines are shown in green breaking down and reconnecting with plasma pockets (green circles in the center). (Image credit: A. Bransgrove et al. Physical Review Letters 2021
Einstein's theory general relativity still holds, even when it comes to "balding" black hole. This is a new breakthrough in physics.
Black holes are areas of spacetime in which gravity's pull makes it impossible for light or anything else to escape being pulled into them and "eaten." Einstein's theory general relativity predicted that black holes would exist. They are defined by their mass, spin, and electrical charge. This is known as the "no hair" theorem by astronomers.
Magnetic fields are a problem that has remained. To make the no-hair theory true, "eating" material should not alter the primary characteristics of a black hole. Although black holes can "be born" with strong magnetic field, they can also "eat" certain materials and cloud of plasma to gain these magnetic fields.
This problem was investigated by physicists who used a supercomputer to create a simulation of a black hole that is surrounded by plasma. They found that black holes can still sustain magnetic fields. Einstein's theory and the "no hair" theorem also hold true.
Related: What happens in the middle of a black hole
"The no hair conjecture" is a cornerstone in general relativity, study co-author Bart Ripperda said in a statement. He is a research fellow at Flatiron Institute's Center for Computational Astrophysics in New York City, and a postdoctoral fellow in Princeton University in New Jersey. The no-hair conjecture can be broken if a black hole is surrounded by a magnetic field that lasts for a long time. Plasma physics provided a solution that prevented the no-hair conjecture being broken.
The researchers discovered that the magnetic fields around black hole can develop in their simulations. The researchers found that the magnetic field lines surrounding the black hole would soon break down and then reconnect. This created pockets of plasma that were energized with the magnetic field. They would then bubble up and be ejected into space or swallowed by the black hole.
Similar: Black holes in the universe (images).
Ripperda states that theorists did not think of this because they often put their black holes into a vacuum. Ripperda says that plasma is often present in real life and can generate and sustain magnetic fields. This is consistent with your "no-hair" conjecture.
The real reason the no-hair theory was saved is that scientists discovered that this process quickly depleted the magnetic field, until it disappeared completely.
The rate at which this depletion occurred was 10% faster than the speed of light.
Ripperda stated, "The fast connection saved the no hair conjecture."
This work was described in a July 27th publication in Physical Review Letters.