What is a Black Hole?
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A black hole is a concentration of mass great enough that the force of gravity prevents anything past its event horizon from escaping it except through quantum tunnelling behaviour (known as Hawking Radiation). The gravitational field is so strong that the escape velocity past its event horizon exceeds the speed of light. This implies that nothing, not even light, inside the event horizon can escape its gravity. It is, however, theorized that wormholes can provide an exit path for energy or matter. The term "black hole" is widespread, even though it does not refer to a hole in the usual sense, but rather a region of space from which nothing can return.\n\nThe existence of black holes in the universe is well supported by astronomical observation, particularly from studying X-ray emission from X-ray binaries and active galactic nuclei.
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General relativity (as well as most other metric theories of gravity) not only says that black holes can exist, but in fact predicts that they will be formed in nature whenever a sufficient amount of mass gets packed in a given region of space, through a process called gravitational collapse. For example, if you compressed the Sun to a radius of three kilometers, about four millionths of its present size, it would become a black hole. As the mass inside the given region of space increases, its gravity becomes stronger — or, in the language of relativity, the space around it becomes increasingly deformed. Eventually gravity gets so strong that nothing can escape, an event horizon is formed, and matter and energy must inevitably collapse into a singularity.
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A black hole is a concentration of mass great enough that the force of gravity prevents anything from escaping it except through quantum tunnelling behaviour (known as Hawking Radiation). The gravitational field is so strong that the escape velocity near it exceeds the speed of light. This implies that nothing, not even light, can escape its gravity.This makes this object invisible to the rest of the universe,hence the word "black". The term "black hole" is widespread, even though it does not refer to a hole in the usual sense, but rather a region of space from which nothing can return.\n\nThe existence of black holes in the universe is well supported by astronomical observation, particularly from studying X-ray emission from X-ray binaries and active galactic nuclei.\n\nGeneral relativity (as well as most other metric theories of gravity) not only says that black holes can exist, but in fact predicts that they will be formed in nature whenever a sufficient amount of mass gets packed in a given region of space, through a process called gravitational collapse. For example, if you compressed the Sun to a radius of three kilometers, about four millionths of its present size, it would become a black hole. As the mass inside the given region of space increases, its gravity becomes stronger   or, in the language of relativity, the space around it becomes increasingly deformed. Eventually gravity gets so strong that nothing can escape, an event horizon is formed, and matter and energy must inevitably collapse into a singularity.\n\nA quantitative analysis of this idea led to the prediction that a star remaining about three times the mass of the Sun at the end of its evolution, will almost inevitably shrink to the critical size needed to undergo a gravitational collapse. Once collapse starts, it cannot be stopped by any physical force, and a black hole is created. This is because there is a limit to the strength of materials due to the fact that the speed of sound, related to the materials stiffness, cannot be greater than the speed of light.\n\nStellar collapse will generate black holes containing at least three solar masses. Black holes smaller than this limit can only be created if their matter is subjected to sufficient pressure from some source other than self-gravitation. The enormous pressures needed for this are thought to have existed in the very early stages of the universe, possibly creating primordial black holes which could have masses smaller than that of the Sun.\n\nSupermassive black holes are believed to exist in the centres of most, (if not all) galaxies, including our own Milky Way. This type of black hole contains millions to billions of solar masses, and there are several models of how they might have been formed. The first is via gravitational collapse of a dense cluster of stars. A second is by large amounts of mass accreting onto a "seed" black hole of stellar mass. A third is by repeated fusion of smaller black holes. Finally it may be possible to construct such a black hole by the collapse of a large gas cloud via an intermediate stage of a relativistic star.\n\nCertain models of unification of the four fundamental forces allow the formation of micro black holes under laboratory conditions. These postulate that the energy at which gravity is unified with the other forces is comparable to the energy at which the other three are unified, as opposed to being the Planck energy (which is much higher). This would allow production of extremely short-lived black holes in terrestrial particle accelerators. No conclusive evidence of this type of black hole production has been presented, though even a negative result
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The gravatational pull from a black hole is so strong that the likelyhood of an object being released is slim at best. The reason it is called a black hole is because gravity is so strong it even absorbs and disburses the waves and particals that make up light. Most scientists believe that even atomic coheasion is lost so that the smallest particals of the nuclious are torn apart.
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LAYMAN'S THEORY\n\nBlack holes are objects so massive and compact that no physical body or signal—not even light—can escape from their gravitational pull once it has crossed the so-called "event horizon" around the black hole (for a black hole of the mass of our sun the event horizon would have a radius of just 3 km, hence black holes are comparably small objects in astronomical terms). Besides the frequent stellar mass black holes (which are thought to be generated at the death of stars about 10 times or more massive than our sun) there is a second class of black holes, which reside in the centers of almost all galaxies and are a million to billion times as massive as our sun. Such so-called supermassive black holes are thought to be the central engine of "Quasars," the most distant and luminous objects known in the universe. Their electromagnetic emission is thought to arise when gas heats up to temperatures of million of degrees before falling beyond the event horizon of a supermassive black hole. In order to find evidence for the existence of such objects, one has to show that so much matter is concentrated in such a small volume that all alternatives to black hole can be excluded—e.g., dense clusters of dark astrophysical bodies such as planets, neutron stars, etc. This is a difficult task in extragalactic systems because of their incredibly large distance. The center of our home galaxy, the Milky Way, however, is about 100 times closer than our next major neighbour galaxy, the Andromeda galaxy. Therefore the undertaking of finding strong direct evidence for the existence of supermassive black holes is most easily done in the Milky Way. For probing the gravitational field at the center of the Milky Way one can use stars as test particles. Imagine the following scenario: If our sun did not give off any light, we would still know of its existence because the gravitational pull of the Sun (along with the angular momentum of the Earth) makes our home planet move around it once a year. In a similar way we have observed the movements of stars close to the supposed supermassive black hole, called Sagittarius A*, in the center of our Milky Way for over a decade. A star was found that moves around Sagittarius A* once every 15 years. By inferring the properties of its orbit with the help of Kepler's laws it was straightforward to show that the (dark) object that forces the star onto its orbit must have about 3.5 million times as much mass as our sun. Furthermore, this mass must be concentrated into a volume just about three times as large as our solar system. Since there is no other known physical object with these properties that can be stable over a significant length of time (compared to the lifetime of our galaxy of about 10 billion years) we concluded that the Sagittarius A* is indeed a supermassive black hole.
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A black hole isn't necessarily big or heavy. Any mass M which is compressed to \n\nSchwarzschild Radius: R = 2*G*M/c²\n\ngravitational constant: G = 6,6742/10^11 m³/(kg*m²)\nspeed of light: c = 2,9979*10^8 m/s\n\n\nwill collapse and form a black hole, theoretically. If you have such a thing and want to carry it around you have to isolate it from surronding matter because everything touching the event horizont R will fall into it. But that's science fiction. Rumours say that romulans use tiny black holes for their warp drives and call them quantum singularities.\n\nHawking Radiation\nhttp://en.wikipedia.org/wiki/Hawking_radiation
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A black hole is a concentration of mass great enough that the force of gravity prevents anything past its event horizon from escaping it except through quantum tunnelling behaviour (known as Hawking Radiation). The gravitational field is so strong that the escape velocity past its event horizon exceeds the speed of light. This implies that nothing, not even light, inside the event horizon can escape its gravity. It is, however, theorized that wormholes can let one exit a black hole. The term "black hole" is widespread, even though it does not refer to a hole in the usual sense, but rather a region of space from which nothing can return.\n\nThe existence of black holes in the universe is well supported by astronomical observation, particularly from studying X-ray emission from X-ray binaries and active galactic nuclei.\nContents\n\nHistory\n\nThe concept of a body so massive that not even light could escape it was put forward by the English geologist John Michell in a 1783 paper sent to the Royal Society. At that time, the Newtonian theory of gravity and the concept of escape velocity were well known. Michell computed that a body 500 times the radius of the Sun and of the same density would have, at its surface, an escape velocity equal to the speed of light, and therefore would be invisible. In his words:\n\nIf the semi-diameter of a sphere of the same density as the Sun were to exceed that of the Sun in the proportion of 500 to 1, a body falling from an infinite height towards it would have acquired at its surface greater velocity than that of light, and consequently supposing light to be attracted by the same force in proportion to its vis inertiae (inertial mass), with other bodies, all light emitted from such a body would be made to return towards it by its own proper gravity.\n\nAlthough he thought it unlikely, Michell considered the possibility that many such objects that cannot be seen might be present in the cosmos.\n\nIn 1796, the French mathematician Pierre-Simon Laplace promoted the same idea in the first and second edition of his book Exposition du Systeme du Monde. It disappeared in later editions. The whole idea gained little attention in the 19th century, since light was thought to be a massless wave, not influenced by gravity.\n\nIn 1915, Einstein developed the theory of gravity called General Relativity. Earlier he had shown that gravity does influence light. A few months later, Karl Schwarzschild gave the solution for the gravitational field of a point mass, showing that something we now call a black hole could theoretically exist. The Schwarzschild radius is now known to be the radius of the event horizon of a non-rotating black hole, but this was not well understood at that time. Schwarzschild himself thought it was not physical.\n\nIn the 1920s, Subrahmanyan Chandrasekhar argued that special relativity demonstrated that a non-radiating body above 1.44 solar masses, now known as the Chandrasekhar limit, would collapse since there was nothing known at that time that could stop it from doing so. His arguments were opposed by Arthur Eddington, who believed that something would inevitably stop the collapse. Both were correct, since a white dwarf more massive than the Chandrasekhar limit will collapse into a neutron star. However, a neutron star above about three solar masses will itself become unstable against collapse due to similar physics.\n\nIn 1939, Robert Oppenheimer and H. Snyder predicted that massive stars could undergo a dramatic gravitational collapse. Black holes could, in principle, be formed in nature. Such objects for a while were called frozen stars since the collapse would be observed to rapidly slow down and become heavily redshifted near the Schwarzschild radius. The mathematics showed that an outside observer would see the surface of the star frozen in time at the instant where it crosses that radius. However, these hypothetical objects were not the topic of much interest until the
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A black hole is a concentration of mass great enough that the force of gravity prevents anything past its event horizon from escaping it except through quantum tunnelling behaviour (known as Hawking Radiation). The gravitational field is so strong that the escape velocity past its event horizon exceeds the speed of light. This implies that nothing, not even light, inside the event horizon can escape its gravity. It is, however, theorized that wormholes can let one exit a black hole. The term "black hole" is widespread, even though it does not refer to a hole in the usual sense, but rather a region of space from which nothing can return.\n\nThe existence of black holes in the universe is well supported by astronomical observation, particularly from studying X-ray emission from X-ray binaries and active galactic nuclei.
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By black hole and singularity we mean two different things: \nA black hole is just the area around a singularity, where the escape velocity is equal to or greater than the speed of light. The event horizon itself forms before the singularity. \n\nIf you use Schwarzchild coordinates, you'll also come up with a singularity at the event horizon, but that's only because of the coordinate system. With a different set of coordinates - Kruskal-Szekeres or Eddington-Finkelstein - the singularity at the event horizon will disappear and the math works out to singularity at r = 0.
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a black hole is a region of spacetime from which nothing can escape because of gravity, and yes, they exist.  this was not a very detailed answer, but i may write more later.  you can follow the link below.\n\nhttp://en.wikipedia.org/wiki/Black_hole
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Black holes, in astronomy, celestial object of such extremely intense gravity that it attracts everything near it and in some instances prevents everything, including light, from escaping. The term was first used in reference to a star in the last phases of gravitational collapse (the final stage in the life history of certain stars; see stellar evolution) by the American physicist John A. Wheeler.\n\nGravitational collapse begins when a star has depleted its steady sources of nuclear energy and can no longer produce the expansive force, a result of normal gas pressure, that supports the star against the compressive force of its own gravitation. As the star shrinks in size (and increases in density), it may assume one of several forms depending upon its mass. A less massive star may become a white dwarf, while a more massive one would become a supernova. If the mass is less than three times that of the sun, it will then form a neutron star. However, if the final mass of the remaining stellar core is more than three solar masses, as shown by the American physicists J. Robert Oppenheimer and Hartland S. Snyder in 1939, nothing remains to prevent the star from collapsing without limit to an indefinitely small size and infinitely large density, a point called the “singularity.”\n\nAt the point of singularity the effects of Einstein's general theory of relativity become paramount. According to this theory, space becomes curved in the vicinity of matter; the greater the concentration of matter, the greater the curvature. When the star (or supernova remnant) shrinks below a certain size determined by its mass, the extreme curvature of space seals off contact with the outside world. The place beyond which no radiation can escape is called the event horizon, and its radius is called the Schwarzschild radius after the German astronomer Karl Schwarzschild, who in 1916 postulated the existence of collapsed celestial objects that emit no radiation. For a star with a mass equal to that of the sun, this limit is a radius of only 1.86 mi (3.0 km). Even light cannot escape a black hole, but is turned back by the enormous pull of gravitation.\n\nIt is now believed that the origin of some black holes is nonstellar. Some astrophysicists suggest that immense volumes of interstellar matter can collect and collapse into supermassive black holes, such as are found at the center of some galaxies. The British physicist Stephen Hawking has postulated still another kind of nonstellar black hole. Called a primordial, or mini, black hole, it would have been created during the “big bang,” in which the universe was created (see cosmology). Unlike stellar black holes, primordial black holes create and emit elementary particles, called Hawking radiation, until they exhaust their energy and expire. It has also been suggested that the formation of black holes may be associated with intense gamma ray bursts. Beginning with a giant star collapsing on itself or the collision of two neutron stars, waves of radiation and subatomic particles are propelled outward from the nascent black hole and collide with one another, releasing the gamma radiation. Also released is longer-lasting electromagnetic radiation in the form of X rays, radio waves, and visible wavelengths that can be used to pinpoint the location of the disturbance.\n\nBecause light and other forms of energy and matter are permanently trapped inside a black hole, it can never be observed directly. However, a black hole can be detected by the effect of its gravitational field on nearby objects (e.g., if it is orbited by a visible star), during the collapse while it was forming, or by the X rays and radio frequency signals emitted by rapidly swirling matter being pulled into the black hole. A small number of possible black holes have been detected. The first discovered (1971) was Cygnus X-1, an X-ray source in the constellation Cygnus. In 1994 astronomers employing the Hubble Space Telescope annou
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Black holes aren't holes in the sense that you're thinking of. A black hole is a region of spacetime (it has 3+1 dimensions like everything else) that has an event horizon (a spherical region) that nothing can escape from.\nTaking the rubber sheet analogy (this is 2+1 dimensional, two spatial dimensions, 1 time dimension), suppose there is a spherical mass placed on the stretched sheet. Depending on how massive that mass is, the sheet around the mass will be circularly distorted, creating a potential energy well. You can roll smaller masses by it. If you roll the smaller mass with too little tangent velocity, it will spiral into the larger mass. If you roll it with a great enough tangential velocity, it may change direction, but it will go right through the potential energy well.\nA black hole has a certain region of its potential energy well (the region inside the event horizon) where no velocity you give a particle will be enough to get it back out of the energy well; all particles entering the event horizon will spiral into the singularity at the center. Part of the reason for this is the limit placed on massive particle accelerations of only being able to accelerate up to the speed of light in vacuum. It is interesting to note that outside the event horizon (assuming a non-spinning black hole), gravity behaves classically. Ie., if the Sun were to collapse into a black hole (which it doesn't have the mass to do), the radius of its event horizon would be less than the current radius of the Sun, so the solar system would continue as usual; the gravitational field outside the event horizon is unchanged.\nAlso, a black hole need not be caused by the death of a star. Primordial black holes are hypothesized to be black holes that formed during the chaotic spacetime of the early universe.
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I'm not sure what a blackhole is, But I have heard that it is a star that has such a strong gravitational pull that even light can't escape.
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The current scientific theory holds that black holes are formed when stars of sufficient mass (about 3x the mass of our Sun) reach the end of their life and collapse down into a singularity, which is, in essence, an infinitely small point with a huge amount of gravity - gravity so powerful that not even light can escape it's pull if it gets too close. It is also thought that black holes can be formed from smaller masses if external energy/pressure is exerted to squeeze the mass into a singularity.\nNot sure if there's any direct experimental evidence of creation, but there is evidence that they exist. Cosmologists use several different methods to detect blacks holes, such as by looking for light being bent and/or disappearing as it travels from remote stars towards us, and also by looking for bursts of x-rays that are given off as matter is sucked into the back hole and destroyed.\nFun fact: current evidence and theory suggests that the center of the Milky Way is a giant black hole that was formed as the densly packed stars in the center collapsed and sucked each other in.
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Things that enter a black hole do not "implode," and black holes and the big bang are two uttern non-connected things.\n\nshort answer day!
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try here\nhttp://en.wikipedia.org/wiki/Black_hole
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Search black hole in the internet.