"Black Holes Are Bald"… Einstein's Hypothesis Was Correct [Reading Science]

NYU Flatiron Institute, Recent Simulation Results Resolve 'Magnetic Field' Issue

The Event Horizon Telescope captured this image of the supermassive black hole in the center of the galaxy M87. (Image credit: EHT Collaboration)

[Asia Economy Reporter Kim Bong-su] The hypothesis that the 'black hole,' predicted by Albert Einstein through the general theory of relativity, is 'bald (no-hair)' has recently been reaffirmed.

According to space-specialized media Space.com on the 4th, scientists at the Computational Astrophysics Center of the Flatiron Institute in New York City published a paper on this topic in the international academic journal 'Physical Review Letters' on the 27th of last month.

A black hole is a celestial body with gravity so strong that it even pulls in light. It was once called a Dark Star or Frozen Star, but since the 1960s, the name 'black hole' has been widely used.

It was defined when Einstein announced the general theory of relativity in 1915. In particular, Einstein predicted that black holes differ only by mass, spin, and charge, and that all other physical properties are the same. Scientists call Einstein's definition the bald, or no-hair theorem. Unlike other celestial bodies, which vary in surface gravity or average density depending on size even if they have the same mass, black holes are determined solely by these three physical quantities. The name comes from the fact that they have almost no unique properties that can distinguish them, like human hair. The term 'black hole' also carries a somewhat sexual metaphor, as it was used as slang for female genitalia in France.

However, there was one obstacle to the no-hair theorem: magnetic fields. For Einstein's definition to hold, a black hole must not change its properties regardless of what it swallows. But black holes generate magnetic fields when absorbing objects and create plasma clouds that can maintain magnetic fields around them. If a black hole has a long-lasting magnetic field, Einstein's theorem that only mass, spin, and charge determine the black hole's characteristics would be invalidated.

However, recent simulations by the Flatiron Institute in New York City confirmed that magnetic fields around black holes evolve rapidly, appearing and dissipating quickly. They also discovered that plasma pockets activated by these magnetic fields inflate like bubbles and are either released into space or absorbed by the black hole. Notably, the bald black hole theory of Einstein was supported by the finding that magnetic fields are expelled at very high speeds?about 10% of the speed of light?before they completely disappear during this process.

Bart Ripperda, a researcher at the Flatiron Institute, explained, "Previous scientists considered black holes to be in a vacuum state, so they did not think about this. However, in reality, there is often plasma around black holes, and plasma can maintain and generate magnetic fields, which aligns with the no-hair theorem."