A report on Black hole

Direct image of a supermassive black hole at the core of Messier 87
Animated simulation of a Schwarzschild black hole with a galaxy passing behind. Around the time of alignment, extreme gravitational lensing of the galaxy is observed.
Simulated view of a black hole in front of the Large Magellanic Cloud. Note the gravitational lensing effect, which produces two enlarged but highly distorted views of the Cloud. Across the top, the Milky Way disk appears distorted into an arc. Published in 2019.
Gravitational time dilation around a black hole
The ergosphere is a region outside of the event horizon, where objects cannot remain in place.
Gas cloud being ripped apart by black hole at the centre of the Milky Way (observations from 2006, 2010 and 2013 are shown in blue, green and red, respectively).
Artist's impression of supermassive black hole seed
Simulated event in the CMS detector: a collision in which a micro black hole may be created
This artist's impression depicts the paths of photons in the vicinity of a black hole. The gravitational bending and capture of light by the event horizon is the cause of the shadow captured by the Event Horizon Telescope.
Predicted appearance of a non-rotating black hole with toroidal ring of ionised matter, such as has been proposed as a model for Sagittarius A*. The asymmetry is due to the Doppler effect resulting from the enormous orbital speed needed for centrifugal balance of the powerful gravitational attraction of the hole.
Black hole with corona, X-ray source (artist's concept)
NASA simulated view from outside the horizon of a Schwarzschild black hole lit by a thin accretion disk.
Blurring of X-rays near black hole (NuSTAR; 12 August 2014)
A Chandra X-Ray Observatory image of Cygnus X-1, which was the first strong black hole candidate discovered
Magnetic waves, called Alfvén S-waves, flow from the base of black hole jets.
Detection of unusually bright X-Ray flare from Sagittarius A*, a black hole in the centre of the Milky Way galaxy on 5January 2015
Simulation of gas cloud after close approach to the black hole at the centre of the Milky Way.
An infographic explaining in detail the appearance of a black hole. The photon sphere surrounds the black hole's shadow.

Region of spacetime where gravity is so strong that nothing – no particles or even electromagnetic radiation such as light – can escape from it.

- Black hole
Direct image of a supermassive black hole at the core of Messier 87

119 related topics with Alpha

Overall
According to general relativity, objects in a gravitational field behave similarly to objects within an accelerating enclosure. For example, an observer will see a ball fall the same way in a rocket (left) as it does on Earth (right), provided that the acceleration of the rocket is equal to 9.8 m/s2 (the acceleration due to gravity at the surface of the Earth).

General relativity

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Geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of gravitation in modern physics.

Geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of gravitation in modern physics.

According to general relativity, objects in a gravitational field behave similarly to objects within an accelerating enclosure. For example, an observer will see a ball fall the same way in a rocket (left) as it does on Earth (right), provided that the acceleration of the rocket is equal to 9.8 m/s2 (the acceleration due to gravity at the surface of the Earth).
Light cone
Schematic representation of the gravitational redshift of a light wave escaping from the surface of a massive body
Deflection of light (sent out from the location shown in blue) near a compact body (shown in gray)
Ring of test particles deformed by a passing (linearized, amplified for better visibility) gravitational wave
Newtonian (red) vs. Einsteinian orbit (blue) of a lone planet orbiting a star. The influence of other planets is ignored.
Orbital decay for PSR 1913+16: time shift (in s), tracked over 30 years (2006).
Orbital decay for PSR J0737−3039: time shift (in s), tracked over 16 years (2021).
Einstein cross: four images of the same astronomical object, produced by a gravitational lens
Artist's impression of the space-borne gravitational wave detector LISA
Simulation based on the equations of general relativity: a star collapsing to form a black hole while emitting gravitational waves
This blue horseshoe is a distant galaxy that has been magnified and warped into a nearly complete ring by the strong gravitational pull of the massive foreground luminous red galaxy.
Penrose–Carter diagram of an infinite Minkowski universe
The ergosphere of a rotating black hole, which plays a key role when it comes to extracting energy from such a black hole
Projection of a Calabi–Yau manifold, one of the ways of compactifying the extra dimensions posited by string theory
Simple spin network of the type used in loop quantum gravity
Observation of gravitational waves from binary black hole merger GW150914

These predictions concern the passage of time, the geometry of space, the motion of bodies in free fall, and the propagation of light, and include gravitational time dilation, gravitational lensing, the gravitational redshift of light, the Shapiro time delay and singularities/black holes.

This is the first direct image of a supermassive black hole, located at the galactic core of Messier 87. It shows radio-wave emission from a heated accretion ring orbiting the object at a mean separation of 350 AU, or ten times larger than the orbit of Neptune around the Sun. The dark center is the event horizon and its shadow. The image was released in 2019 by the Event Horizon Telescope Collaboration.

Supermassive black hole

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This is the first direct image of a supermassive black hole, located at the galactic core of Messier 87. It shows radio-wave emission from a heated accretion ring orbiting the object at a mean separation of 350 AU, or ten times larger than the orbit of Neptune around the Sun. The dark center is the event horizon and its shadow. The image was released in 2019 by the Event Horizon Telescope Collaboration.
An artist's conception of a supermassive black hole surrounded by an accretion disk and emitting a relativistic jet
Artist's impression of stars born in winds from supermassive black holes.
Simulation of a side view of a black hole with transparent toroidal ring of ionized matter according to a proposed model for Sgr A*. This image shows the result of bending of light from behind the black hole, and it also shows the asymmetry arising by the Doppler effect from the extremely high orbital speed of the matter in the ring.
Inferred orbits of 6 stars around supermassive black hole candidate Sagittarius A* at the Milky Way galactic center
Artist's impression of a supermassive black hole tearing apart a star. Below: supermassive black hole devouring a star in galaxy RX J1242−11 – X-ray (left) and optical (right).
Hubble Space Telescope photograph of the 4,400 light-year-long relativistic jet of Messier 87, which is matter being ejected by the supermassive black hole at the center of the galaxy
The supermassive black hole of NeVe 1 is responsible for the Ophiuchus Supercluster eruption – the most energetic eruption ever detected. ''From: Chandra X-ray Observatory

A supermassive black hole (SMBH or sometimes SBH) is the largest type of black hole, with its mass being on the order of millions to billions of times the mass of the Sun.

Linearly polarised gravitational wave

Gravitational wave

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Gravitational waves are disturbances or ripples in the curvature of spacetime, generated by accelerated masses, that propagate as waves outward from their source at the speed of light.

Gravitational waves are disturbances or ripples in the curvature of spacetime, generated by accelerated masses, that propagate as waves outward from their source at the speed of light.

Linearly polarised gravitational wave
Primordial gravitational waves are hypothesized to arise from cosmic inflation, a faster-than-light expansion just after the Big Bang (2014).
The effect of a plus-polarized gravitational wave on a ring of particles
The effect of a cross-polarized gravitational wave on a ring of particles
The gravitational wave spectrum with sources and detectors. Credit: NASA Goddard Space Flight Center
Two stars of dissimilar mass are in circular orbits. Each revolves about their common center of mass (denoted by the small red cross) in a circle with the larger mass having the smaller orbit.
Two stars of similar mass in circular orbits about their center of mass
Two stars of similar mass in highly elliptical orbits about their center of mass
Artist's impression of merging neutron stars, a source of gravitational waves
Two-dimensional representation of gravitational waves generated by two neutron stars orbiting each other.
Now disproved evidence allegedly showing gravitational waves in the infant universe was found by the BICEP2 radio telescope. The microscopic examination of the focal plane of the BICEP2 detector is shown here. In January 2015, however, the BICEP2 findings were confirmed to be the result of cosmic dust.
A schematic diagram of a laser interferometer
LIGO measurement of the gravitational waves at the Hanford (left) and Livingston (right) detectors, compared to the theoretical predicted values.

Sources that can be studied this way include binary star systems composed of white dwarfs, neutron stars, and black holes; events such as supernovae; and the formation of the early universe shortly after the Big Bang.

Simulated view of a Neutron star with accretion disk. The disk appears distorted near the star due to extreme gravitational lensing

Neutron star

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Collapsed core of a massive supergiant star, which had a total mass of between 10 and 25 solar masses, possibly more if the star was especially metal-rich.

Collapsed core of a massive supergiant star, which had a total mass of between 10 and 25 solar masses, possibly more if the star was especially metal-rich.

Simulated view of a Neutron star with accretion disk. The disk appears distorted near the star due to extreme gravitational lensing
Radiation from the rapidly spinning pulsar PSR B1509-58 makes nearby gas emit X-rays (gold) and illuminates the rest of the nebula, here seen in infrared (blue and red).
Simplified representation of the formation of neutron stars.
Gravitational light deflection at a neutron star. Due to relativistic light deflection over half the surface is visible (each grid patch represents 30 by 30 degrees). In natural units, this star's mass is 1 and its radius is 4, or twice its Schwarzschild radius.
Cross-section of neutron star. Densities are in terms of ρ0 the saturation nuclear matter density, where nucleons begin to touch.
Computer renders of a neutron star with accretion disk, with magnetic field lines projected, showing bursts of powerful X-rays and Radio Waves. The simulations are taken from 2017 data from NASA's NuSTAR and Swift, and ESA's XMM-Newto observatories
P–P-dot diagram for known rotation-powered pulsars (red), anomalous X-ray pulsars (green), high-energy emission pulsars (blue) and binary pulsars (pink)
NASA artist's conception of a "starquake", or "stellar quake".
Central neutron star at the heart of the Crab Nebula.
Circinus X-1: X-ray light rings from a binary neutron star (24 June 2015; Chandra X-ray Observatory)
An artist's conception of the pulsar planet PSR B1257+12 C, with bright aurorae.
The first direct observation of a neutron star in visible light. The neutron star is RX J1856.5−3754.
Different Types of Neutron Stars (24 June 2020)
Artist's impression of disc around a neutron star RX J0806.4-4123.

Except for black holes and some hypothetical objects (e.g. white holes, quark stars, and strange stars), neutron stars are the smallest and densest currently known class of stellar objects.

Artist's conception of gravity pulling mass away from a star and into a black hole

Gravity

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Fundamental interaction which causes mutual attraction between all things with mass or energy.

Fundamental interaction which causes mutual attraction between all things with mass or energy.

Artist's conception of gravity pulling mass away from a star and into a black hole
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English physicist and mathematician, Sir Isaac Newton (1642–1727)
An illustration of the Schwarzchild metric, which describes spacetime around a spherical, uncharged, and nonrotating object with mass
The 1919 total solar eclipse provided one of the first opportunities to test the predictions of general relativity
An initially-stationary object that is allowed to fall freely under gravity drops a distance that is proportional to the square of the elapsed time. This image spans half a second and was captured at 20 flashes per second.
If an object with comparable mass to that of the Earth were to fall towards it, then the corresponding acceleration of the Earth would be observable.
A falling tower for gravity experiments, University of Bremen, Germany.
Gravity acts on stars that form the Milky Way.
The LIGO Hanford Observatory located in Washington, United States, where gravitational waves were first observed in September 2015.
Rotation curve of a typical spiral galaxy: predicted (A) and observed (B). The discrepancy between the curves is attributed to dark matter.

The most extreme example of this curvature of spacetime is a black hole, from which nothing—not even light—can escape once past the black hole's event horizon.

Image of Sirius A and Sirius B taken by the Hubble Space Telescope. Sirius B, which is a white dwarf, can be seen as a faint point of light to the lower left of the much brighter Sirius A.

White dwarf

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Stellar core remnant composed mostly of electron-degenerate matter.

Stellar core remnant composed mostly of electron-degenerate matter.

Image of Sirius A and Sirius B taken by the Hubble Space Telescope. Sirius B, which is a white dwarf, can be seen as a faint point of light to the lower left of the much brighter Sirius A.
A comparison between the white dwarf IK Pegasi B (center), its A-class companion IK Pegasi A (left) and the Sun (right). This white dwarf has a surface temperature of 35,500 K.
The white dwarf cooling sequence seen by ESA's Gaia mission
Artist's impression of the WD J0914+1914 system.
Internal structures of white dwarfs. To the left is a newly formed white dwarf, in the center is a cooling and crystallizing white dwarf, and the right is a black dwarf.
Artist's impression of debris around a white dwarf
Comet falling into white dwarf (artist's impression)
The merger process of two co-orbiting white dwarfs produces gravitational waves
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White dwarfs are thought to be the final evolutionary state of stars whose mass is not high enough to become a neutron star or black hole.

Picture of space infalling into a Schwarzschild black hole at the Newtonian escape speed. Outside/inside the horizon (red), the infalling speed is less/greater than the speed of light. At the event horizon, the infalling speed equals the speed of light. Credit: Andrew Hamilton, JILA

Hawking radiation

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Picture of space infalling into a Schwarzschild black hole at the Newtonian escape speed. Outside/inside the horizon (red), the infalling speed is less/greater than the speed of light. At the event horizon, the infalling speed equals the speed of light. Credit: Andrew Hamilton, JILA

Hawking radiation is thermal radiation that is theorized to be released outside a black hole's event horizon because of relativistic quantum effects.

Spacetime diagram showing a uniformly accelerated particle, P, and an event E that is outside the particle's apparent horizon. The event's forward light cone never intersects the particle's world line.

Event horizon

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Event horizon is a boundary beyond which events cannot affect an observer.

Event horizon is a boundary beyond which events cannot affect an observer.

Spacetime diagram showing a uniformly accelerated particle, P, and an event E that is outside the particle's apparent horizon. The event's forward light cone never intersects the particle's world line.

In 1958, David Finkelstein used general relativity to introduce a stricter definition of a local black hole event horizon as a boundary beyond which events of any kind cannot affect an outside observer, leading to information and firewall paradoxes, encouraging the re-examination of the concept of local event horizons and the notion of black holes.

At NASA's StarChild Learning Center, c. 1980s

Stephen Hawking

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English theoretical physicist, cosmologist, and author who, at the time of his death, was director of research at the Centre for Theoretical Cosmology at the University of Cambridge.

English theoretical physicist, cosmologist, and author who, at the time of his death, was director of research at the Centre for Theoretical Cosmology at the University of Cambridge.

At NASA's StarChild Learning Center, c. 1980s
Stephen Hawking in 1966
Hawking at an ALS convention in San Francisco in the 1980s
Hawking with string theorists David Gross and Edward Witten at the Strings Conference in January 2001, TIFR, India
Hawking at the Bibliothèque nationale de France to inaugurate the Laboratory of Astronomy and Particles in Paris, and the French release of his work God Created the Integers, 5 May 2006
Hawking with University of Oxford librarian Richard Ovenden (left) and naturalist David Attenborough (right) at the opening of the Weston Library, Oxford, in March 2015. Ovenden awarded the Bodley Medal to Hawking and Attenborough at the ceremony.
Hawking holding a public lecture at the Stockholm Waterfront congress centre, 24 August 2015
Hawking taking a zero-gravity flight in a reduced-gravity aircraft, April 2007
Stephen Hawking's memorial stone in Westminster Abbey
President Barack Obama talks with Hawking in the White House before a ceremony presenting him with the Presidential Medal of Freedom on 12 August 2009
Hawking in Monty Python's “Galaxy Song” video at the comedy troupe's 2014 reunion show, Monty Python Live (Mostly)
Hawking being presented by his daughter Lucy Hawking at the lecture he gave for NASA's 50th anniversary, 2008
The Blackboard from Hawking's Office on display in the Science Museum

Hawking's scientific works included a collaboration with Roger Penrose on gravitational singularity theorems in the framework of general relativity, and the theoretical prediction that black holes emit radiation, often called Hawking radiation.

Artist's impression of a stellar-mass black hole (left) in the spiral galaxy NGC 300; it is associated with a Wolf–Rayet star

Stellar black hole

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Artist's impression of a stellar-mass black hole (left) in the spiral galaxy NGC 300; it is associated with a Wolf–Rayet star

A stellar black hole (or stellar-mass black hole) is a black hole formed by the gravitational collapse of a star.