A black hole is a region of spacetime where gravity is so strong that nothing, including light and other electromagnetic waves, is capable of possessing enough energy to escape it. Einstein's theory of general relativity predicts that a sufficiently compact mass can deform spacetime to form a black hole. The boundary of no escape is called the event horizon. A black hole has a great effect on the fate and circumstances of an object crossing it, but it has no locally detectable features according to general relativity. In many ways, a black hole acts like an ideal black body, as it reflects no light. Moreover, quantum field theory in curved spacetime predicts that event horizons emit Hawking radiation, with the same spectrum as a black body of a temperature inversely proportional to its mass. This temperature is of the order of billionths of a kelvin for stellar black holes, making it essentially impossible to observe directly.
General relativity, also known as the general theory of relativity and Einstein's theory of gravity, is the geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of gravitation in modern physics. General relativity generalises special relativity and refines Newton's law of universal gravitation, providing a unified description of gravity as a geometric property of space and time or four-dimensional spacetime. In particular, the curvature of spacetime is directly related to the energy and momentum of whatever matter and radiation are present. The relation is specified by the Einstein field equations, a system of second order partial differential equations.
The following is a timeline of gravitational physics and general relativity.
A strange star is a hypothetical compact astronomical object, a quark star made of strange quark matter.
A gravastar is an object hypothesized in astrophysics by Pawel O. Mazur and Emil Mottola as an alternative to the black hole theory. It has usual black hole metric outside of the horizon, but de Sitter metric inside. On the horizon there is a thin shell of matter. The term "gravastar" is a portmanteau of the words "gravitational vacuum star". Further theoretical considerations of gravastars include the notion of a nestar, or a second gravastar nested within the first one.
Brandon Carter, is an Australian theoretical physicist who explores the properties of black holes, and was the first to name and employ the anthropic principle in its contemporary form. He is a researcher at the Meudon campus of the Laboratoire Univers et Théories, part of the CNRS.
Theoretical astronomy is the use of analytical and computational models based on principles from physics and chemistry to describe and explain astronomical objects and astronomical phenomena. Theorists in astronomy endeavor to create theoretical models and from the results predict observational consequences of those models. The observation of a phenomenon predicted by a model allows astronomers to select between several alternate or conflicting models as the one best able to describe the phenomena.
Roy Patrick Kerr is a New Zealand mathematician who discovered the Kerr geometry, an exact solution to the Einstein field equation of general relativity. His solution models the gravitational field outside an uncharged rotating massive object, including a rotating black hole. His solution to Einstein's equations predicted spinning black holes before they were discovered.
An exotic star is a hypothetical compact star composed of exotic matter, and balanced against gravitational collapse by degeneracy pressure or other quantum properties.
Gravitational-wave astronomy is an emerging field of science, concerning the observations of gravitational waves to collect relatively unique data and make inferences about objects such as neutron stars and black holes, events such as supernovae, and processes including those of the early universe shortly after the Big Bang.
In particle physics, hexaquarks, alternatively known as sexaquarks, are a large family of hypothetical particles, each particle consisting of six quarks or antiquarks of any flavours. Six constituent quarks in any of several combinations could yield a colour charge of zero; for example a hexaquark might contain either six quarks, resembling two baryons bound together, or three quarks and three antiquarks. Once formed, dibaryons are predicted to be fairly stable by the standards of particle physics.
ICRANet, the International Center for Relativistic Astrophysics Network, is an international organization which promotes research activities in relativistic astrophysics and related areas. Its members are four countries and three Universities and Research Centers: Armenia, the Federative Republic of Brazil, Italian Republic, the Vatican City State, the University of Arizona (USA), Stanford University (USA) and ICRA.
Charles William Francis Everitt is a US-based English physicist working on experimental testing of general relativity.
ICRA, the International Center for Relativistic Astrophysics is an international research institute for relativistic astrophysics and related areas. Its members are seven Universities and four organizations. The center is located in Rome, Italy.
Manuela Campanelli is a distinguished professor of astrophysics of the Rochester Institute of Technology,. She also holds the John Vouros endowed professorship at RIT and is the director of its Center for Computational Relativity and Gravitation. Her work focuses on the astrophysics of merging black holes and neutron stars, which are powerful sources of gravitational waves, electromagnetic radiation and relativistic jets. This research is central to the fields of relativistic astrophysics and gravitational-wave astronomy.
Stuart Louis Shapiro is an American theoretical astrophysicist, who works on numerical relativity with applications in astrophysics, specialising in compact objects such as neutron stars and black holes.
Vitaly Kocharovsky is a Russian-American physicist, academic and researcher. He is a Professor of Physics and Astronomy at Texas A&M University.
Vladimir Kocharovsky is a Russian physicist, academic and researcher. He is a Head of the Astrophysics and Space Plasma Physics Department at the Institute of Applied Physics of the Russian Academy of Sciences and a professor at N.I. Lobachevsky State University of Nizhny Novgorod.
Madappa Prakash is an Indian-American nuclear physicist and astrophysicist, known for his research on the physics of neutron stars and heavy-ion collisions.
