General Relativity believers talk about gravity as warping of space -time;what is the fabric of space -time ?
147684
the fabric is space-time :)\nlook curvature of space-time is just a model to understand what happened so you don't need to assume it is a material.\nBut I believe that the space is different from null. Space is a creature because it has physical properties.
320062
Warping of spacetime, analogy of spacetime as a piece of elastic fabric are just ways to make some mathematical concepts more understandable for laymen. There r hardcore mathematical description behind all these. It doesn't explain anything because u cannot understand the counterintuitive concept behind it and the hard math. It does describe gravity pretty well. Describe. Like all science, it describe. It explains how. It does not explain why. Why is a philosophical, or maybe religious, question.\n\nAnother analogy. An ant walk on a piece of paper. It walk straight ahead. When u bent the paper, u see the ant's path as a curve. If the paper is invisible, it appear as if some force has bent the path of the ant who is just walking a straightline on itself. This is too simplistic but hope u get the picture.\n\nCurvature of spacetime is for description of the geometry of paths. With the presence of gravity, the spacetime get curved, and the geometry of a straightline on a 1 spatial and one time dimentions spacetime becomes a curved line on a 3 spatial and 1 time dimensions spacetime, the spacetime we observe.\n\nWhy would an object with mass has gravitational field around it? why does electron have charges? why does exchange of photons create electric charges? u will never ever get down to the answer because whatever ingredient u used to cook up the answer need to be explain further. it is a never ending process. General Relativity doesn't explain why gravity, but describe how gravity.\n\n\n\n\nthey did not move to spacetime description from Newtonian, in an attempt to explain the why of gravity. They move becoz the spacetime description is more accurate in describing gravity. science cannot really explain why. If one day, they discovered gravitational pull is due to movement of gravitons between masses, the next question would be, why such movement could create gravitational pull. so instead of looking at this as an explanation of WHY, these gravitons would just be a even more detailed DESCRIPTION of HOW gravity works. No scientist know WHY things work. Nobody does. But a lot of scientists do know HOW things work. In the case of gravity, many does.
78675
The poster before me gave an excellent answer which is that nobody really knows. I just wanted to point you to a very cool experiment about how mass warps space.\n\nAnother very profound question to ask would be why are gravitational mass and inetial mass so nearly (if not exactly) equal?
246282
I don't know why there are so many Cosmic Ridlles like Aether and Curvature of Time and even worse Space; Who does really understand it. And how can they play the fiddle in Space That is my Riddle!
126640
In general relativity, mass affects space and time, causing what we call gravity, and time dilation. The equations predicted that clocks in a gravity field would run more slowly, although the effect is very slight for most masses that we are familiar with, like the Earth. It has been measured and agrees well with predictions.\n\nSimilarly, the equations predicted that light would be bent around a mass, like the sun, and this has also been proved to be correct. In fact, strong gravity sources can create illusions, sometimes splitting the image of a light source behind a high-gravity object so it appears to us to be two separate images.\n\nA new discovery is that the rotation of a gravity source, like the sun or a galaxy, causes "frame dragging", that is, distorts spacetime like water around a spinning ball, also predicted by Einstein's theory.\n\nThere are a lot of good science sites on the web for this information.
418600
That's a mystery that the physicists haven't figured out.  \n\nAristotle theorized that the objects "want" to go toward the middle of the earth.  We might laugh, but think he has a point.  A common theme throughout reality is that things want to go toward equilibrium, and if you keep wanting to go toward something, or have a pull toward something, then you aren't at equilibrium.\n\nPhysicists theorize about gravitons, particles that are gravity.  I think that's wrong.  I believe that gravity is working on the stuff that space is made of.  I believe that the natural state of the universe is probably a singularity.  And when it's not in this state, it tries to return to this state.
801582
No, physicists have always known that gravity is the one "force" that we really still don't understand. Now it is true that at macroscopic or large distance scales, we understand gravity very well through Einstein's General Relativity Theory. But at the quantum level, the scale of sub-atomic particles, we have no idea how gravity works there. And the most interesting thing is that when we try to probe and understand gravity at the quantum level, we find that we have to abandon all our currently understanding of space and time, as well as the notion of 3-dimensional space.
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gravity is the curvature of space-time.  The more mass an object has, the more gravity it has, the bigger the curvature.  Imagine a rubber sheet with a bowling ball on it.  The sheet is space-time and curves around the ball.  No energy necessary.
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No.\n\nBefore Einstein physicists tried to explain the properties of light by assuming there was this fluid like medium (Aether) everywhere in the universe.\n\nEinstein showed that such assumptions could not explain observation. Instead he eventually introduced a new idea of space time, and explained gravity as curvature in space. The differences between space time and Aether are like night and day. In no ways does space time curvature resemble a fluid of any sorts. In fact they talk about two totally different things. Aether deals with the properties of light, space time curvature deals with the properties of gravity.
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There is currently no porperly accepted quantum theory of gravity. \n\nSome candidate theories include the graviton as the exchange particle that would carry the gravitational force. Gravity has a very special role in physics because it act on everything, and so effectively shapes space-time. A quantum theory of gravity has to allow for the graviton to interact with every other particle, including the other force carrying particles, which would be unique behaviour.\n\nThe classical theory of gravity is that it operates by curving space-time (the theory of General Relativity which, contrary to what you may expect, is classical physics). General relativity is smooth down to the smallest scale, unlike quantum mechanics.
92597
Okay. Everything that has mass has gravity. You and I have our own innate gravity. So does your pencil, your computer, the air you breathe. \n\nIf you think of space-time (see Einstein) as the surface of a huge trampoline on which everything sits, then mass sits on top of that trampoline. But if you put a bowling ball on a trampoline, it puckers the surface and smaller things are drawn towards it, and it is drawn towards the smaller thing, if only a little bit. Similarly, if you roll a marble around the bowling ball, it will circle many times before it finally crashes into the bowling ball. (That how orbiting works.)\n\nThis is simplified, of course, but it helps to understand the concepts. If you are interested in the subject, I would recommend reading Billions and Billions by Carl Sagan.\n\nGood Luck!
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to date, the best description of gravity is given by general relativity.  general relativity was published in 1915.  however, physicists are trying to develop a more accurate quantum description of gravity because of the contradictions between general relativity and quantum physics.  both general relativity and quantum physics are supported by incredibly precise observations.\n\nhttp://en.wikipedia.org/wiki/General_relativity\n\nthis is really bizarre.  it is the holographic universe.  the name comes from the hologram, which is a two dimensional film that has information stored on it and will project a three dimensional image, if laser light is put thru it.  physicists can describe the universe with two sets of laws: one three dimensional set with gravity and one two dimensional set without gravity, and there is no way to tell them apart.  this second set essentially states that gravity is an illusion.  see "the illusion of gravity", scientific american, november 2005
486183
I find it to be quite fascinating.  Although mind-bending as well (11 dimensions - my brain hurts just thinking about it).  I don't know if it is correct or not (well, no one knows for sure), but it seems to have potential, particularly with resolving the Relativity/Quantum Physics battle.
1157163
Who said you could see it? You can make an educated guess that there is gravity due to its consumption of materials but you cant actually see gravity!
308069
String theory is a step in the direction for the GUT.  But string theory itself is out the window.  GUT will mostly likely be a hybrid of string and quantum.  Each answer some of the most important fundamental questions, but not the same ones and not all of them.  Essentially string theory just states matter is made up of vibrating strings of energy.  For a good book on the subject, three roads to quantum gravity by smolin is excellent.  He is partial to quantum theory but gives both justice and goes a little into some radical ideas that don't branch from either quantum or relativity.
435368
I think u could visit this website for the general relativity:\n\nhttp://archive.ncsa.uiuc.edu/Cyberia/NumRel/GenRelativity.html
937989
Gravitons are theoretical "virtual particles"...it is an attempt that quantum mechanics makes to explain gravity...but general relativity with its curve in spacetime explains it much better.