what is black hole in space?
368768
A black hole is were a star once lived. Try this link for more details:\n\nhttp://www.cem.msu.edu/~cem181h/projects/98/TBA/Created.htm
914906
Its a remain of a exploded star. After explosion, under it own gravitational force, it compacts so much that after certain point its escape velocity crosses the speed of light. So even light cannot escape from it. Thats why its called Black Hole.\nCheck out this URL and get to know more of this interesting thing of this Universe.\nhttp://en.wikipedia.org/wiki/Black_hole
596967
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.
345783
Yes, black holes can move in space,\npartially due to the law of conservation of momentum (and inertia), if it was moving before it became a black hole, it will continue to move,\nand a black hole is affected by gravity like other objects.\n\nIt has been theorized, and some experimental evidence confirms, that larger (super-massive) black holes reside within many galaxy's centers.  As we can observe, galaxies can, and do, move around...thus if they have a black hole at thier center, the black hole moves as well.
23482
In astronomy, an object so massive that nothing, not even light, can escape its gravitation. Black holes were given their name because they absorb all the light that falls on them. The existence of black holes was first predicted by the general theory of relativity. Supermassive black holes have been found in the centers of many galaxies. Stellar black holes are thought to arise from the death of very massive stars. Astronomers expect to find many stellar black holes in the Milky Way. \n\n\nFiguratively, the term black hole is used to refer to a total disappearance: “They never saw the man again — he might as well have fallen into a black hole.”
330944
A black hole is a very large star, many times more massive than our Sun, that has collapsed under its own gravity (Usually, the star doesnt collapse because the nuclear reactions occuring in its core counter the gravitational force) The gravitational field around a black hole is so strong that not even light can escape
468852
A black hole, by definition, doesn't emit light; photons can enter the event horizon of a black hole, but cannot emerge from it. If you can't see a black hole, then how do you know it's there?? In order to detect a black hole, you have to be devious and use indirect methods. \nThe method of detecting dark objects by noting their gravitational effect on luminous objects is a very old one. \n\nThe planet Neptune was first discovered from its gravitational effect on the planet Uranus. \nThe white dwarf Sirius B was first discovered from its gravitational effect on the star Sirius A. \nA black hole can be discovered from its gravitational effect on luminous matter (stars and/or hot gas).\n\nIf a black hole exists in a close binary system, it can be detected indirectly. Gas ripped from the companion star will spiral in toward the black hole. As it does so, it is heated up (by tidal heating, and by friction as it rubs against neighboring gas). The hot gas emits X-rays as it undergoes its death spiral to the event horizon. (Once it's inside the event horizon, we don't see the gas any more, but it's highly visible as long as it's outside.) If you are hunting for black holes, it's good to start by looking for binary star systems which are also strong X-ray sources. \n\nAbout a dozen other black hole candidates, with masses up to 10 solar masses or so, have been found in binary star systems within our galaxy. (We don't expect too many black hole stellar remnants, given the scarcity of the extremely massive stars which are their precursors.) \nAn interesting recent development in astronomy is that supermassive black holes (that is, black holes more than a million times the mass of the Sun) are found at the centers of many galaxies. Our own galaxy, for instance, has a black hole with mass 2.6 million Msun at its center, 8000 parsecs away from us. Our own galactic black hole is actually fairly wimpy. The Andromeda Galaxy, 700,000 parsecs away, has a black hole with a mass of 30 million Msun. \n\nHow do you go about hunting such supermassive black holes? As usual, you go about it indirectly, by looking at the orbital motion of gas and stars near the centers of galaxies. For instance, the observation of stars near the center of our own galaxy has revealed that they are orbiting a massive object with M = 2.6 million Msun. The closest star to this massive object comes within 17 light-hours (120 A.U.) of its center. The only plausible way to cram 2.6 million solar masses of stuff into a sphere 120 A.U. in radius is to make it all into a single big black hole. (For instance, if you tried to make a cluster of a million neutron stars 120 A.U. in radius, the collisions between neutron stars would make them all merge into a single big black hole within a few hundred thousand years.)
1136303
A black hole is not actually a hole, but a physical object in space, consisting of ultra compact particals, contained in such a small area that thier gravitational pull is much stronger than any other celestial body of comperable size....  Basically you put all the matter and gravitational pull from a large star into the volume of a small moon... particles captured by a black hole are crushed and added to its composition. This in theory includes photons (light and other energy)as well.  As for whether black holes are hoax's or not.. the answer is no... we can see their effects on star near them, including gases that are syphoned, and other gravitational interactions.  Additionally when matter approaches a black hole and is accellerated, it reaches an energy level at the even horizon where xrays are emited, but not captured, which in turn we can also detect.  Though there is much we do not know about them, they definately exist, and most likely in much greater numbers than we oringinally thought.
1169308
It's a planet.  Planets are too small to be blackholes.  I will ignore the second part of your question.
128460
It might be, or it might be a neutron star. We do not really know. \n\nThere are some other objects in the sky which are much more certainly black holes, from their masses and other properties.
770597
well Black Hole is hole which is created when a star after growing for millions of years erupts. It is created actually due to little gravititional force which the black hole has & it starts acting like a tornado tries to bring everything towards it's centre. it is so powerful that even light cannot escape.\nas u know it forms when a star erupts so it is noemally located in space
755373
Black holes are a concept in cosmology and theoretical physics.  The idea of going into one doesn't really fit in with the science. \n\nUsing a mechanical model of the universe, black holes are extremely dense concentrations of matter with such a high gravitational force that everything (including light) is sucked in and cannot escape.  If you went near a black hole, you would be broken down into subatomic particles and crammed into the lump of compressed matter at the centre.\n\nHowever, quantum physics gives an alternative theory.  Black holes could be the ways in and out of shortcuts across the universe so that something sucked into one could be spat out of another.  This is probably something best not tried at home.
628731
black hole \n\nIn 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."
203553
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.
603896
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.
1059153
A black hole is a singularity in spacetime. In other words, its a place where the stress energy caused by a gravitating mass is so large that spacetime curves to a single point.\n\nIt is not possible to know what happens on the other side of a black hole because all of the laws of physics are discontinuous at its boundary. Thats not to say that they change inside the black hole, its just to say that there is no experiment that can be done or observation made outside the black hole that can ever tell you what is going on inside it.\n\nFalling into a black hole is odd. As the gravitational field increases, time relative to places with a lower gravitational field runs slower. At the event horizon of the black hole (just before you fell in) the escape velocity is the speed of light, and so it would be akin to travelling at the speed of light (which is impossible). Time for you would extend infinitely, even those outside would see you fall in.
10068
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