In Newtonian physics, gravity describe as a force but in General Relativity gravity is no more the normal force we feel or experience but some kind of curvature of the spacetime cause by mass and energy(mass-energy equivalence from special relativity). So if there is a mass, then if some other mass smaller compare to it will roll to the center of the larger mass in a curve trajectory in global sense, but in local sense all the smaller mass experince is only a straight trajectory( this is where the 1st Newton's law!). It would be the case as in 4the post said if explain in terms of the fabric manners.
About the explanation of light is, light is some kind of energy with no mass, so it would also be drag by the larger mass source as ordinary particle. From this we can expain about the bending of light at gravitational sources(like our sun). When the gravitational source is too large(like black hole), the time required for light escape from it is larger and larger and even became infinity in the event horizon, so the time as if freezed near the event horizon and we know nothing from black hole because the light signal can never reach us.( Not quite sure about the explanation at this paragraph in more precise and technical sense but almost the case as we know today).
Before we have the Hawking radiation theory, we just expect that we can never reach to the information stored inside a black hole, but after it, we expect to get some information form the Hawking radiation. ( almost i can tell... the rest i also quite understand) Intersted people can go read black hole thermodynamics and about some quantum information theory.

45 dimensions? M-theory can reduce the dimensions to only 12 and only 12 is fit the thoery. For lqg we don't even look at extra dimesions but we foliate the spacetime into space and we take no more time but the evolution of the spin network(which is space) and this evolution of network forms our ordinary 4 dimesion view of spacetime - spinfoam.
Anyway, this thread is talking about the macro physics, so no need of quantum theory and quantum gravity to discuss, just general relativity.
btw, the white hole that convivencia is still a conjecture, not even a theory and thus proven yet. in the theory, star collapse to black hole and "sucks" everything around it, emits Hawking radiation and other kind of radiation plus heat, while white hole doing the opposite thing, "spouts" out everything the black hole sucks, create a new star or galaxy or even universe and this two "hole" connected by wormhole.

This post has been edited by nobunaga84: Sep 17 2009, 09:12 PM

1st of all, in science, this is called astrophysics, not astrology. astrology is more to the horoscope prediction etc... that's still not a branch of science. for the science of observation on the stars etc, that's astronomy, for the science to learn about the birth of universe etc or in precise word learn the universe as a whole, that's called cosmology. each of this still have their branches, like quantum cosmology etc.

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Added on October 5, 2009, 1:08 pmabout the extra dimensions, u can read string theory. string theory as one of the popular approach to the quantum gravity require extra dimension to support its consistency. in supergravity we need 13(if i'm not mistaken) dimension in total, in M theory we need 11 dimensions, in brane localized gravity we need 5 dimensions. in the theory of extra dimensions, all the extra dimensions out of our ordinary 4 dimensions is compactified(e.g. like Calabi-Yau manifolds).

anyway, in another popular approach to quantum gravity, loop quantum gravity we doesn't require extra dimension.

This post has been edited by nobunaga84: Oct 5 2009, 01:10 PM

Well the spring explanation u talked on is just a simple analogy. in fact the whole life of a star is just a fighting between gravity and nuclear reaction. if the expansion due to nuclear fusion win, then the star keep on expanding, so, when the fuel is out, the expansion will tend to be smaller, so expansion to outward direction is getting more and more weaker than gravity. when gravity grew stronger so is the bending of the light become more and more. so, when the gravity grew stronger untill a certain limit (this is quite simple but in fact a complicate process. i cant talk in more technical terms here, involve too many things) even the light from the star itself is bent to the inward direction towards the star(think of this as a 180 degree), so light cannot escape from the star. since all observables involve light signal, so no light means that we cannot see it directly, so it is black in the area! because the gravity is so strong that even light cannot escape from falling back into the star, so it is like a hole sucking everything, even the light while we cannot see and setect the hole directly, so in simple word this is a "black hole".

am i making any confuse? comment on it.

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Added on October 8, 2009, 3:16 pmWell, if u seriously interested in this and wants to make it ur career, the n u shld convince ur parents that u are not playing around with it! regarding the job prospect, it does have little selection if campare with engineering or economics or even administration, but, there are many job u can take too if u search carefully.
Malaysians(including me) are too ignorant in this kind of things that they think that a researcher cannot have a good income compare to others. yes, we cannot make an income of 1 million per yr or even per week unless we invent something which is every valuable, but we still can have a moderate income which is sometimes is better than an office worker. our working time is flexible also. so u have to conviced ur parents that u are serious! this is thew most important thing.

actually i'm quite happy seeing that there are still people in Malaysia who interestered in all this kind of knowledge. this kind of knowledge is not useless but have a variety of usage, some already applied in other field, some maynot, probably due to other reason like we still have no technology that can apply them etc.

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Added on October 8, 2009, 3:23 pmSchwarzchild radius derived when Schwarzchild solvingfor the exact solution of Einstein equation for the spherical, non rotating mass. Any non-rotating and non-charged mass that is smaller than the Schwarzschild radius forms a black hole. The solution of the Einstein field equations is valid for any mass M, so in principle (according to general relativity theory) a Schwarzschild black hole of any mass could exist if conditions became sufficiently favorable to allow for its formation. The Schwarzschild black hole is characterized by a surrounding spherical surface, called the event horizon, which is situated at the Schwarzschild radius, often called the radius of a black hole.

quote from wikipedia. is it clear for u?

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Added on October 8, 2009, 3:30 pmthere are in deed distinction between black holes and worm hole as u said. and should have been tell u is that worm hole is not neccessarily connecting black hole, they are just a warp through spacetime which we can travel from 1 point to other through a short cut. but anyway there are in fact a hypotetical object only. no proof of a worm hole is given yet. even the black hole has not been found yet, although we do have a few candidate which we suspect that they are black hole. u can search for candidate for balck holes if u interested. in fact the supermassive black hole in the center of our galaxy is one of the candidate for balck hole.

regarding why it is black, read my above argument.

This post has been edited by nobunaga84: Oct 8 2009, 03:35 PM

non Euclidean geometry.