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black hole | white hole | dark halo | massive compact halo object | inversely proportional to the wavelength | inversely proportional to its momentum | MACHO | hypothetical | uncertainty principle | hidden mass | A gravitationally collapsed mass inside the Schwarzschild radius (q.v.), from which no light, matter, or signal of any kind can escape. A black hole occurs when the escape velocity of a body becomes the velocity of light (2GM / R = c2). If an object with the mass of the Sun had a radius of 2.5 km, it would be a black hole. Black holes represent one of the possible endpoints of stellar evolution for stars very much more massive than the Chandrasekhar limit. | |
naked singularity | | | singularity | | | | | | | A singularity that will be visible and communicable to the outside world. | |
Schwarzschild singularity | | | singularity | | | | | | | The center of a black hole. According to Einstein's theory of general relativity, the entire mass of a black hole is concentrated at a point at its center, the "singularity". It is believed that quantum mechanical effects, not included in the theory, would cause the mass to spread out over a tiny but nonzero region, thus preventing an infinite density of matter and doing away with the singularity. | |
white hole | black hole | | singularity | | | | | | | The time-reversal of a black hole. A white hole is a singularity from which matter emerges unpredictably, but into which matter cannot enter. The initial singularity of the standard big bang theory is an example of a white hole. It can be shown that the creation of a new universe from a false vacuum bubble in the context of classical general relativity would require a white hole singularity, which means essentially that it cannot be done, even in principle. However, a false vacuum bubble could conceivably grow to become a new universe through a process of quantum tunneling. | |
wormhole | | | singularity | | | | | | | A tube-like region of space connecting one region of the universe to another. | |