Talk:Graviton

I find what looks like three different questions, so I'm giving three separate replies.

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This page needs at leas copyediting, maybe revision of contents.

From a historical viewpoint it is quite intruiging, whether the graviton exists as elementary particle or not. 150 years ago physicists were searching for the calory. In the end the calory was not a particle but a property. [G.K.]

More like 250 years ago. They had no framework. The "calorie" was just an idea.

In contrast, gravitons have not been postulated to explain something presently incomprehensible, but are a seemingly inevitable consequence of two of our best theories of physics, GR and QM. Their biggest role in physics is to tell theorists whether or not their equations have a chance of talking about quantum gravity. These equations will normally be far more interesting than mere gravitons, and maybe someday one of them will be testable.--192.35.35.34 20:05, 16 Feb 2005 (UTC)

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Why must gravitons be for attractive gravity? Gravity is, in fact, noticeably repulsive at extragalactic scales. (Think about universal expansion! and inflation.) How else could the universe counter an unsaturated force from a pseudosingularity? lysdexia 07:10, 16 Oct 2004 (UTC)

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Who says that's "gravity"? Inflation results from GR mixed with GUT symmetry breaking.

As it is, the "attraction" in question, when talking about quantizing gravity, is what gravity does "matter to matter". In other words, the people studying quantum gravity are studying this situation, and here is where they expect to find gravitons. The fun with GR, of course, is that space-time bending and warping is an added bonus. Quantization and the graviton concept does not touch these issues, although many people would like to find a way to do so.--192.35.35.34 20:05, 16 Feb 2005 (UTC)

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The following is not a question concerning the article itself, but asking if the graviton itself has a function, while the below train of thought is correct:

How could a grivaton be able to transport the information if there is gravity (or not) through a black holes rim (schwarzschild radius) in order to make the singularity have gravitation, while it has to speed up the information faster than light to do this.

-nerdi (de.wp.org) 9.12.2004 Thank you in advance

The short answer is that the treatment of force by exchange of virtual particles is really a heuristic for certain complicated mathematical calculations, whose validity as a calculation is unknown in regards to gravity. In other words, "no comment".

So perhaps the real question is how can physicists even think to be looking for quantum gravity with a theory that has gravitons escaping from a black hole all time, whence nothing (or essentially nothing) is supposed to escape? The answer is that virtual particles do not have most of the properties of real particles. In particular, they are not bound by the speed of light. So the Schwarzschild radius, defined as where the escape velocity is c, only restricts real particles.

In fact, an elementary argument says QFT + SR requires antimatter to exist, as follows: if two particles exchange a virtual particle that happens to be going faster than light, there must be a frame of reference that thinks the particle exchange happened in the reverse order. The virtual particle in this second frame has all the properties of the antiparticle to the virtual particle in the original frame.

Again, this is just a heuristic reading of certain mathematical calculations. There is no "information" involved, and SR is not violated. Note that this goes back to the birth of QFT in the thirties. In other words, it's a non-issue for black holes because it's a non-issue in general.--192.35.35.34 20:05, 16 Feb 2005 (UTC)

This entry needs more mathematical discussion. Showing how linearized gravity can be quantized would be nice.

Dark energy implies anti-gravity. Which makes sense why univerese expands like it does. Since it is 70% of Universe acording to wiki article and so little is known about them, it's futile to simply ignore a posible relationship. --Cool Cat ^{My Talk} 15:42, 20 Mar 2005 (UTC)

No. Dark energy is a negative pressure. No antigravity. In fact, there can't be antigravity unless GR is seriously wrong. --Pjacobi 16:53, 2005 Mar 20 (UTC)

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Could this not raise questions about Antigravitons, though?

I believe not because gravity is not supposed to be a specific interaction. In fact there is no evidence for a gravitational force. -- Orionix 08:21, 11 Apr 2005 (UTC)

Ok, but if we think with scope about Newtonian physics, particularly Newton's third ("Whenever one body exerts force upon a second body, the second body exerts an equal and opposite force upon the first body.") the supposed force in this example is cultivated by 'gravity' and the opposing is the 'NRF'. Due to the nature of the topic (to theorize that such a particle as a graviton could exist), could you not also be led to believe that the cancellation of the two forces (gravity and NRF) are both diametric opposites? --- I apologize about the poor wording and how ill thought-through my theory is. Also for using a basic principle with outdated physics. Please feel free to correct, coment and criticise.