ZelmersZoetrop said:I was reading Michio Kaku's book Hyperspace when I came across his statement that black holes have to have another side to be consistent. I'm curious, since Godel showed that a given energy-momentum tensor does not nessecarily produce a unique metric, why must the kerr-newman solution be the only description of a charged rotating singularity?
The Kerr-Newman solution is a mathematical solution to the Einstein field equations in general relativity that describes the spacetime around a rotating, charged black hole. It was first derived by Roy Kerr in 1963 and later extended by Ezra Newman.
The Kerr-Newman solution takes into account the effects of rotation and charge, while the Schwarzschild solution only describes a non-rotating, uncharged black hole. This means that the Kerr-Newman solution is more realistic and applicable to real-world astrophysical objects.
The Kerr-Newman solution has three key parameters: mass, angular momentum, and electric charge. These parameters determine the size, shape, and electromagnetic properties of the black hole described by the solution. It also has an inner and outer event horizon, as well as an ergosphere, which is a region of spacetime where objects cannot remain stationary due to the effects of rotation.
The Kerr-Newman solution is an example of the no-hair theorem, which states that a black hole can be completely described by its mass, angular momentum, and electric charge. This means that all other information about the matter that formed the black hole is lost, hence the term "no-hair". The Kerr-Newman solution is one of the few known solutions that satisfy this theorem.
The Kerr-Newman solution has been used to study the properties and behavior of black holes in astrophysics, as well as to test the predictions of general relativity in extreme gravitational fields. It has also been applied in other areas of physics, such as string theory and quantum gravity, to better understand the nature of spacetime and the universe.