Do you know what black holes are?
367170
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
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.
17
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.
794668
Well, black holes are mysterious simply because they are regions where light itself cannot escape!  If you go by general relativity black holes are singularities where space and time lose their meaning in the rational sense!  As for black holes leading to some location, most likely that is not the case.  Such an object is a wormhole, which is a theoretical solution to Einstein's field equations like black holes are.  But, wormholes have not been observed in nature and they are unstable to the point where if even a tiny amount of mass enters the wormhole it will collapse it and destroy the matter before it ever gets to the other side!  So, that being true a black hole has no opening somewhere else, because if it did it would collapse the same way.  However, Stephen Hawking showed that black holes do dissipate over many billions of years because of quantum tunneling.  Turns out some matter/energy actually gets out of the black hole!  So, we still have alot to learn about the nature of black holes, because we still have to learn alot about gravity!
989936
Curved spacetime.\n\nThere is nothing unduly special about the event horizon (ie it has no discontinuities). And very large black holes do not have unduly curved spacetime at their event horizons (the curvature of the supermassive black hole at the centre of our galaxy is on 20 times greater than that here on Earth, and here on Earth the curvature is pretty much undetectable).
529002
The obvious answer is black holes. But other kinds are non reflective nebulae and dark matter.
762962
no, but i can tell you what we think it is:\n\nit is a star whose gravity is too great for the nuclear fusion in its core to negate.  it collapses in on itself and goes supernova.  then it is a neutron star.  if the gravity is still too great, it collapses some more and becomes a black hole.  its gravity is so strong that light itself cannot escape it (thus it is 'black').  they are suspected to be at the center of many galaxies, especially quasars and other active galaxies.  one is believed to be at the center of our own galaxy, the milky way.\n\nonce again, no one has really seen one, just the indirect evidence that one exists (strange star orbits, gas being sucked into nothing, strange bursts of some kind of rays (can't remember what kind) coming out of the poles, etc.\n\neverybody is pretty convinced that they exist.  its just kinda hard to prove.\n\nps the idiot down there who said black holes are dead galaxies has no clue what he is talking about. please ignore him.  and its not the size of an atom, its an infinitely small point, the swartzchild point.
144870
We have no idea what happens to any matter inside a black hole. The laws of physics that we know do not apply.
473814
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.
1057805
A black hole is a star that has collapsed to the point that the empty space in the atoms no longer exists.  They are solid matter, though not matter that exists anywhere on earth.  They are called black holes because the gravitation force is so large that even light cannot excape.  The link below gives a decent explanation.
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
115592
I'm not sure I understand the question.  However, newton's laws of gravitation do not describe anything like black holes.  Black holes fall out of Einstein's theories of general relativity.
575553
Nope.  Whoever told you this has been watching too much science fiction.\n\nBlack holes are just collapsed stars, and their gravity is no bigger than any other star (except to things that are very close to it).  There are enormous black holes at the center of galaxies, but these don't pose a threat to the majority of the galaxy ... and the earth is way out near the edge of our galaxy.  And there is no black hole even theorized that is big enough to swallow entire galaxies.
453327
Who knows about black holes, but I do know an a** hole when I see one and those priest are big ones.
1097264
A black hole is an immensely massive (dense, heavy) and immensely small (tiny) object in space that has such a strong electromagnetic and gravitational pull, it sucks light photons into it, making it look like there is a giant hole in the universe.\n\nNothing anywhere on this planet, including in the ocean, is anything like a black hole.
651133
The black hole is where the force of gravity has successfully joined our known universe back with infinitely dimensional space. \n\nSpace is where our universe was born in a disturbance known as the big bang.  \n\nThe black hole is the grand finale to gravity, gravity's 'goal' creating a porthole to where we came from before the big bang.  \n\nGravity is the connection space has with our universe, too stubborn to let us go and will one day bring us back to become nothing and everything with it once again.\n\nPeace Out
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.