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IMAGE: Artist s conception of a rotating black hole accreting matter via an accretion disk and emitting a jet. view more
Credit: NASA/JPL-Caltech
Black holes are considered amongst the most mysterious objects in the universe. Part of their intrigue arises from the fact that they are actually amongst the simplest solutions to Einstein s field equations of general relativity. In fact, black holes can be fully characterized by only three physical quantities: their mass, spin and charge. Since they have no additional hairy attributes to distinguish them, black holes are said to have no hair : Black holes of the same mass, spin, and charge are exactly identical to each other.
Dark matter proponents theorize that most of the known Universe is actually made of material that doesn’t interact with light, making it invisible and undetectable, but that this material accounts for much of the gravitational pull among galaxies. A counter explanation introduced by the Israeli physicist Mordehai Milgrom in 1983, the MOdified Newtonian Dynamics (MOND) theory, says this gravitational pull exists because the rules of gravity are slightly altered. Instead of attributing the excess gravitational pull to an unseen, undetectable dark matter, MOND suggests that gravity at low accelerations is stronger than would be predicted by a pure Newtonian understanding. In addition, MOND makes a bold prediction: the internal motions of an object in the cosmos should not only depend on the mass of the object itself, but also the gravitational pull from all other masses in the Universe the so-called external field effect. Now, astrophysicists from South Korea, the United Kingdom and
Unique prediction of modified gravity challenges dark matter theory phys.org - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from phys.org Daily Mail and Mail on Sunday newspapers.