how can giant black holes emit red light radiation if nothing can escape its gravitational pull.?
339928
Some new theories state that xrays of high energy can escape from a black hole.  This is interesting, because if true, it means that over time the energy of the black hole will leak into space and it will "evaporate".  \n\nAny visible light comes from collisions of particles that are being sucked into the hole, but are not there yet, so the heat (as light) can still escape and be seen.
1117199
Not quite true; while the gravitational field is so immense within the event horizon of a black hole that even light cannot escape it, two different phenomena occur right at the event horizon which provide astronomers with secondary evidence of their presence.  Firstly, all the matter a black hole consumes becomes accelerated by its gravitational pull.  If the matter is a charged particle, acclerating it creates a changing electric and magnetic field around it, which propagates as electromagnetic radiation -- basically light.  Up until the point where it crosses the event horizon, it continues to emit EM radiation which may be detectable from Earth (if enough particles are accelerated at once)  Secondly, there's "Hawking radiation:" the intense curvature of space-time at the event horizon of a black hole causes virtual particles to pop into existence -- a pair, actually, one particle and it's corresponding antiparticle (being opposites, they cancel each other out energy-wise and the universe is still balanced)  In the rest of the universe, when a virtual particle pair appears, the two opposite charges annihilate one another in a (tiny) flash of light, but at the event horizon, there's a good chance that one of the two gets sucked into the black hole while the other goes zinging off in the opposite direction, effectively adding to the mass of the universe.  So a stream of subatomic particles can also sometimes be detected from a black hole.\n\nAlso, because black holes ARE such a big gravity well, they affect stars more distant from us than the black hole is by allowing us to see them via gravitational lensing -- the gravity is enough to bend light from stars that are beyond it enough so that we can see them, but there is a detectable distortion to the image that astronomers can use to determine where the mass causing the lensing is located, and based on what we know of the stars beyond it, can calculate its mass... and if the number they get is huge like a red giant star yet it doesn't glow, that's another good indicator of a black hole in the neighborhood.
839494
As a star gets older it fuses lighter elements into heavier ones. Every moment of a stars life is a delicate balance of the energy from the fusion reactions tryong to blow the star apart while the gravity of the star's mass tries to crush it inward.\n\nThere will be a point in every star's existance that the energy of nuclear fusion is no longer enough to maintain the balance and a new equilibrium of sought. When our sun runs out of hydrogen in roughly 5 billion years it will have to switch to helium and become a red giant star for example. When the star runs out of fusionable elements, it "dies". Depending on how much mass the star had is what happens next.\n\nIn the case of the largest and most massive of stars the result is very dramatic. Without fusionable elements, the gravity crushes the mass of the star down to a size so small that the velocity required to overcome the gravitational pull and escape the surface of the star is greater then the speed of light. Nothing can move faster then light, thus nothing can escape this star.\n\nThis is what a black hole is. You know how the shuttle has to be moving about 11 kilometers a second to escape Earth's pull? If the Earth was a Black Hole, the shuttle would have to be moving faster then the speed of light to escape. This is impossible.\n\nAs for whether or not they exist, it's true that they are hard to spot. However if you watch the matter surronding a black hole there are signs. In Cygnus X-1, there is an object "eating" a blue giant star that may just be a black hole. In fact, astrophysicists have hypothesized that any single star that has more mass then about 45 Suns will eventually become a Black Hole. The theory is that if these stars are left alone, becoming a Black Hole is inevitable.\n\nAs for what happens to light, we know that light goes in, it doesn't come out, and as it gets close it shifts toward red. That's about it.
170312
Are you talking about gravitational lensing?\n\nObviously, nothing, not even light can escape the gravitational pull of a black hole after it crosses the event horizon.\nBut is an object (or light) is a safe enough distance away from the black hole, it just experiences a pull towards it, it is not sucked in for all eternity.\nGravity can be though of as a depression/warping of the space time.  Alll object with mass have gravity, so all objects with mass can bend light.  The more mass an object has, the more light bends.  Since black holes have such an exreamly high mass, it can bend light a lot.\nIn fact it is possible for light to be bent into a circle, traveling round and round, never leaving its "orbit" around the black hole.\n\nIf some object located behind the black hole (from the point of view of the observer) is emmitting light at just the right angle, as the ligh nears the black hole, its path is bent so that it can go around the black hole.  This is known as a gravitational lens.\nThis phenomenon is not exclusive the black holes, our sun can even do this with noticible effects.  I belive one of the experiemnts used to verify the acuracy of the theort of relativity was to calciulate the "actual" position of Mercury compared to where we saw it in the sky.  Since Mercury is so close to the sun, just as it goes around the far side, the light was able to bend enough so that we could see it longer than we should have been able to.
1152122
A star is a big mass of gas. It originated as a hydrogen cloud  that started contracting because gravity pulled it together. When this happens the interior gets denser and hotter. Dense enough and hot enough for fusion reactions to start. The latter produce heat and light that pushes outwards.\n\nThe result is an equilibrium between gravity and the light radiation. The star stabilizes and stays stable for billions of years. The sun is in this stage.\n\nHowever, when the hydrogen is burnt up, the outward pressure is taken away and gravity takes over again. If the mass of this burnt out star is big enough, then there is nothing to counteract gravity.\n\nThe mass of the star will be more and more concentrated in a smaller and small volume. Gravity at the surface will become so strong that not even light can escape from it. \n\nThat is a black hole.
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.
379182
If your talking about light, traveling at the speed of light, yes it can. Black Holes suck in everything, including light. According to Steven Hawking there is only 1 thing that can escape a Black Hole, thermal radiation.
357992
i dont believe so, from watching many episodes on nova , i understand black holes to be tinny[ in size] particles of compressed matter , so compressed as to create an astronomical gravitational force so strong that even light cannot escape. i believe most scientist believe it is a large compressed star; a star the size of our sun compressed to the area of a marble or tennis ball which because of its great gravitational force act like a celestial vacuum cleaner... its real esoteric b.s.
57804
Emit light. A black hole absorbs darkness. And everything else, too.\n\nMypublic... is right. Darkness cannot be absorbed. Darkness is simply the absence of light.\n\nTHE Darkness, on the other hand, is a rockin' '80's throwback band!
660648
A Black hole is formed when a giant star (one thats many many times bigger than our average sized sun) burns up its gaseous energy sources(hydrogen) such that it can no longer sustain the nuclear reactions on its surface. As a result all the massive amount of matter it holds ,pulled by massive gravity collapses towards the center and results in what is called a supernova explosion. However the dense core of the star remains holding alot of matter, say a few billions the time of the mass of the sun but only stretching to a very tiny fraction of the star's original size. This core has so much gravity acting towards the center such that ,nothing including light can escape from it. THIS IS CALLED A BLACK HOLE!\n\nAs of their relevance to US!!! \nWe know black holes exist from the Quasar & Pulsar phenomenon mainly detected by radio telescopes, First, in the distant future where space travel will take us into very deep space, say towards the center of our Galaxy, space travellers must be able to avoid the Event horizon, otherwise they will be sacked ino it.\n\nSecondly, massive gravity seems to bend light that travels near it thus distorting the apparent location of objects whose light has to pass near black holes to reach us. This will have to be considered by astronomers observing distant stellar bodies\n\nLastly, its thought that at the center of our Galaxy-the milky way,there is a giant Black hole and its gravitational pull makes the star systems around it(eg the solar system) to revolve around it in a spiral manner because systems closer to the center rotate faster than the ones further out. So I guess, this particular blackhole is of the same relevance to the solar system as the sun is to the earth!::::::Thankyou
330240
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
943076
You can spin a black hole?   Well aren't you talented...  actually the whole known physical universe is first and foremost a gigantic black hole, and it is in motion.  Before the first star formed the dark spacial universe existed and on the smallest scale there is no empty space, everything is connected.  It has been said that darkness is merely the absence of light, but there's no such thing as nothing, everything is made of something, even the ordinary everyday nighttime darkness, on some immeasurable scale even your shadow is made of something?  Black holes are a different more massive type of darkness comprised of dark physical matter.   There's a theory that every galaxy has one at the center and without it the stars that form a galaxy couldn't exist, and it's probable that it is already spinning, nothing is actually sitting still.  It's estimated the output of light from all the stars should be enough to light up the whole universe, but it doesn't.  Then where does it go, what happens to it, we know on a sub atomic scale it doesn't simply dissipate?  Where does the darkness go when you switch on a light?  When you turn off the light, obviously it's still there, so wasn't it there the whole time?   Well, there are still more questions than answers, and maybe you should be a physicist, perhaps you could find an answer to the enigmas of the infinite machine.
944482
The acceleration due to gravity of a black hole depends on the mass of the black hole.  Each black hole has its own mass, and this determines the strength of gravity at a given distance.  It is a bit inaccurate to say that "the gravitational pull is greater than the speed of light."  It is better to say that the escape velocity is greater than the speed of light, within a certain radius called the event horizon.
5155
Because a "black hole" has a gravitational field so strong, light cannot escape.  Therefore, all we can see is that nothing is there, which appears like "blackness" to us, and since light "falls" into it, it's a "hole".\n\nThus, black hole.
312029
As moses said very well indeed, Nobody knows.\nThe major problem I have with a black hole is why it is called a black hole. If this thing is so dense and gravity is so powerful it would be bending light around at the event horizon so that you'd not even know the black hole is there. The other way to confirm this "black hole" would be to observe the planets remaining in the solar system still rotating around a sun which is not there any more. What you would actually confirm would be, according to the laws of gravitational attraction that two massive bodies are attracting each other. One is the planet you see and the other is the "black hole.\nWe know we can change things by sqeezing them, coal into diamonds etc, but there are some materials such as water that are supposed to be incompressible.\nWhat we are supposed to think is the acceleration gradient is so massive that atoms are stripped into their components.\nThe thing is, if the graviation is so massive beyond the event horizon that things are moving at the speed of light.\nThis is a contradiction according to the relativistic E=MC^2 equation.\nIn order for something to travel at the speed of light it must have no mass.\nWe know light has no rest mass.. I.e. stop some light and you get energy but nothing to look at.\nTherefore we are supposed to assume that a massive body changes into pure energy to reach the speed of light and then turn back to mass when it gets to the centre of the black hole.\nThe conclusion there is neither mass nor energy according to the laws of physics currently at the centre of a black hole.
267839
The universe is expanding more quickly the farther one gets toward the edge. \n\nWe know this because objects seen moving away from us through radio telescopes exibit a red shift, depending upon how fast they are moving away. The light from stars that are farther away from earth show more red shift than those close to earth, indicating that they are moving faster from us then their closer neighboors.\n\nThis implies that the forces of expansion are greater than those of contraction (gravity), and that the fate of the universe is not cyclical (no more big bangs), and that black holes, while locally dense, will never exert enough influence to contribute to large scale contraction of the universe.
985633
Nobody has answered this correctly yet.  Light does not have any rest mass.  The reason why it cannot escape a black hole once inside the event horizon is that the gravitational fiels is so intense that it warps the fabric of spacetime.  At the event horizon, if you were to turn tangent to the event horizon  and shoot a laser beam out straight you would hit yourself in the back.  Any light inside the horizon just spirals in, to where IDK.