"A black hole is a region of spacetime where gravity is so strong that nothing, including light or other electromagnetic waves, has enough energy to escape it."
A region of space-time exhibiting such strong gravitational effects that nothing can escape from it.
General Relativity: The theory of gravitation developed by Albert Einstein that forms the basis for the study of black holes.
Event Horizon: The boundary of a black hole beyond which no information can escape.
Singularity: The infinitely dense point at the center of a black hole.
Black Hole Mechanics: The study of the physical properties of black holes, including their mass, spin, and charge.
Hawking Radiation: The radiation emitted by a black hole due to quantum mechanical effects.
Information Paradox: The problem of reconciling the loss of information that occurs when matter falls into a black hole with the principles of quantum mechanics.
Gravitational Waves: Ripples in space-time that are caused by violent cosmic events such as the merger of black holes.
Supermassive Black Holes: Black holes that are billions of times more massive than our Sun and located at the centers of galaxies.
Black Hole Thermodynamics: The study of the thermodynamic properties of black holes, including their temperature, entropy, and heat capacity.
Black Hole Formation: The processes by which black holes are formed, including the gravitational collapse of massive stars and the mergers of smaller black holes.
Wormholes: Hypothetical tunnels through space-time that could enable faster-than-light travel or time travel.
Black Hole Information Retention: The study of whether or not information that falls into a black hole can be stored or retrieved, and the implications for the foundations of physics.
Cosmic Strings: Theoretical structures that may exist in the universe and could have an effect on the formation and behavior of black holes.
Black Hole Astrophysics: The study of the astrophysical phenomena associated with black holes, such as jets of material that are emitted from the vicinity of their event horizons.
Black Hole Observations: The use of telescopes and other instruments to observe black holes, including the behavior of matter in their vicinity and their effect on the surrounding interstellar medium.
Schwarzschild black hole: A non-rotating, spherically symmetric, and static black hole. It is the simplest type of black hole, named after Karl Schwarzschild, who first described it mathematically in 1916.
Kerr black hole: A rotating black hole, where the singularity is located on an axis of symmetry, and it is distorted into a ring shape. Named after Roy Kerr, who first described this type of black hole in 1963.
Reissner-Nordstrom black hole: A charged black hole with electric charge, named after Hans Reissner and Gunnar Nordstrom, who described it in 1916.
Kerr-Newman black hole: A rotating charged black hole, which is a combination of the Kerr and Reissner-Nordstrom black holes. Named after Ezra Newman, who first described this type of black hole with a charge in 1965.
Primordial black hole: A hypothetical black hole that is believed to have formed during the early universe, before the formation of stars and galaxies. It is thought to be much smaller than other black holes.
Interstellar black hole: A black hole that is formed from the collapse of a massive star, with a mass between 5 and 20 times greater than the mass of the sun.
Supermassive black hole: A black hole that is thought to exist at the center of most galaxies, with a mass millions or billions of times greater than the mass of the sun.
Micro black hole: A hypothetical black hole that is theorized to be very small with a mass on the order of the Planck mass, which is about 22 micrograms.
Naked singularity: A theoretical concept where the singularity of a black hole is exposed, without being protected by an event horizon. This would violate the cosmic censorship hypothesis, which states that singularities must always be hidden by an event horizon.
Fuzzy dark matter black hole: A hypothetical type of black hole that is composed of fuzzy dark matter, which is a type of dark matter that has a wave-like nature.
"The 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."
"It has no locally detectable features according to general relativity."
"A black hole acts like an ideal black body, as it reflects no light."
"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."
"Objects whose gravitational fields are too strong for light to escape were first considered in the 18th century by John Michell and Pierre-Simon Laplace."
"Karl Schwarzschild found the first modern solution of general relativity that would characterize a black hole."
"David Finkelstein, in 1958, first published the interpretation of 'black hole' as a region of space from which nothing can escape."
"The discovery of neutron stars by Jocelyn Bell Burnell in 1967 sparked interest in gravitationally collapsed compact objects as a possible astrophysical reality."
"The first black hole known was Cygnus X-1, identified by several researchers independently in 1971."
"Black holes of stellar mass form when massive stars collapse at the end of their life cycle."
"Supermassive black holes of millions of solar masses may form by absorbing other stars and merging with other black holes."
"There is consensus that supermassive black holes exist in the centres of most galaxies."
"The presence of a black hole can be inferred through its interaction with other matter and with electromagnetic radiation such as visible light."
"Any matter that falls onto a black hole can form an external accretion disk heated by friction, forming quasars, some of the brightest objects in the universe."
"If other stars are orbiting a black hole, their orbits can be used to determine the black hole's mass and location."
"Such observations can be used to exclude possible alternatives such as neutron stars. In this way, astronomers have identified numerous stellar black hole candidates in binary systems."
"The radio source known as Sagittarius A*, at the core of the Milky Way galaxy, contains a supermassive black hole of about 4.3 million solar masses."