"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 where the gravity is so strong that nothing, not even light, can escape.
General Relativity: The theory of gravity developed by Einstein that explains how mass and energy curve the fabric of space-time.
Black Hole Definition and Formation: Understanding what black holes are, and how they form after stars collapse under their own weight.
Event Horizon: The boundary around a black hole beyond which nothing can escape.
Singularity: The point at the center of a black hole where gravitational forces become infinite.
Types of black holes: Understanding the differences between stellar black holes, intermediate black holes, and supermassive black holes.
Gravitational Waves: Ripples in the fabric of space-time caused by the acceleration of massive objects.
LIGO and Virgo Detectors: Understanding the technology behind the detectors used to detect gravitational waves, and how they work.
Binary Black Holes: A pair of black holes that orbit around each other and eventually merge, producing gravitational waves.
Spacetime: Understanding the fabric of space-time and how it is affected by gravity.
Black Hole Entropy: Understanding the thermodynamics of black holes and how they emit radiation.
Astrophysical Jets: The powerful jets of plasma that are emitted by black holes.
Black Hole Information Paradox: The conflict between classical and quantum mechanics over whether information is lost when it falls into a black hole.
Wormholes: Hypothetical tunnels through space-time that might allow for faster-than-light travel.
Hawking Radiation: The process by which black holes emit radiation, named after Stephen Hawking.
Quantum Mechanics: The branch of physics that describes particles on a very small scale, and how it relates to black holes.
Stellar black holes: These are formed when a massive star collapses upon itself under the force of gravity, and its core becomes too dense to resist the inward force. These black holes have masses ranging from a few solar masses up to 100 solar masses.
Intermediate black holes: These black holes have masses between 100 and 100,000 solar masses and are believed to form when the stars in the center of a dense stellar cluster merge.
Supermassive black holes: These are at the center of almost all galaxies and have masses ranging from a few hundred thousand to billions of solar masses. Their formation is unclear, but some theories suggest they result from merging of intermediate black holes or accretion of gas and dust.
Primordial black holes: These are hypothetical black holes that were formed shortly after the Big Bang, and are believed to have masses less than a few solar masses.
Naked black holes: These are black holes with no event horizon, meaning that they can be observed directly without the need for a telescope. Their existence is purely theoretical as no such black hole has been observed to date.
"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."