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How does physics explain the graviton?
Okay, so what happens? 
Quote from: Chemistry4me on 14/03/2009 10:59:40Okay, so what happens? Do you mean why a ball falls to the ground?
Perhaps it is something that physics cannot explain just at this moment? 
mass bends spacetime so the ball is forced to follow that bending.
General Relativity says that objects move towards each other due to the curvature of space that is caused by the presence of matter (matter tells space how to curve and space tells matter how to behave).
I think I'm right in saying that the graviton only exists in Quantum Field Theory. It is basically postulated to make gravity work in the same way as the other known forces: i.e. by the exchange of guage bosons like the W & Z bosons of the weak force.
Quote from: DoctorBeaver on 14/03/2009 11:15:52I think I'm right in saying that the graviton only exists in Quantum Field Theory. It is basically postulated to make gravity work in the same way as the other known forces: i.e. by the exchange of guage bosons like the W & Z bosons of the weak force.Yes, but there is just a little problem: gravity is still not described by quantum mechanics...
You two write at the speed of sound! I couldn't edit my post that you already have written two of them! 
Hmmm... now I'm confused. 
How does physics explain the graviton? Can one of you clever people out there please tell me how physics explains the fact that when I let go of a ball, it falls to the ground? What on Earth is going on here? How does this (hypothetical?) graviton interact with the ball so that it falls to the ground? 
Who the heck comes up with this kind of stuff?!? 
Now to the second question. 
The end of the SUGRA eraThe initial excitement over 11-dimensional supergravity soon waned, as various failings were discovered, and attempts to repair the model failed as well. Problems included: * The compact manifolds which were known at the time and which contained the standard model were not compatible with super-symmetry, and could not hold quarks or leptons. One suggestion was to replace the compact dimensions with the 7-sphere, with the symmetry group SO(, or the squashed 7-sphere, with symmetry group SO(5) times SU(2). * Until recently, the physical neutrinos seen in the real world were believed to be massless, and appeared to be left-handed, a phenomenon referred to as the chirality of the Standard Model. It was very difficult to construct a chiral fermion from a compactification — the compactified manifold needed to have singularities, but physics near singularities did not begin to be understood until the advent of orbifold conformal field theories in the late 1980s. * Supergravity models generically result in an unrealistically large cosmological constant in four dimensions, and that constant is difficult to remove, and so require fine-tuning. This is still a problem today. * Quantization of the theory led to quantum field theory gauge anomalies rendering the theory inconsistent. In the intervening years physicists have learned how to cancel these anomalies.Some of these difficulties could be avoided by moving to a 10-dimensional theory involving superstrings. However, by moving to 10 dimensions one loses the sense of uniqueness of the 11-dimensional theory.The core breakthrough for the 10-dimensional theory, known as the first superstring revolution, was a demonstration by Michael B. Green, John H. Schwarz and David Gross that there are only three supergravity models in 10 dimensions which have gauge symmetries and in which all of the gauge and gravitational anomalies cancel. These were theories built on the groups SO(32) and E_8 \times E_8, the direct product of two copies of E8. Today we know that, using D-branes for example, gauge symmetries can be introduced in other 10-dimensional theories as well.
Why are you talking about me behind my back?
Quote from: Chemistry4me on 16/03/2009 10:26:11Why are you talking about me behind my back? Coz it's easier on the eye than your front 
Mr Chem, that was a sheep trick, introducing Lambert to gravity.http://www.youtube.com/watch?v=LRtKAQJUc3g
To my mind, attempts at unifying gravity with the other forces are pointless because no such unity exists. TOEs are full of fudges & kludges that seem to be no more than mathematicians' playthings. Layer upon layer of complexity is added to patch holes that exist in the theories. Those layers, in turn, have holes in them that require more patches and so on. It's worse than a Microsoft OS (OK, maybe not). By accepting that gravity is totally separate from the other forces we can do away with all that complexity & desperate fine-tuning.
When particle is new, is hot/density and that particle time is slowly!Thats why new particle dont emit energy fast and that why is not giving kinetic energy for expanding atoms nucleus!When particle is old, is not so hot/density and time is not so slowly and thats why particle emit energy fast. Thats why particle giving kinetic energy for expanding atoms nucleus!thats why we stay earth skin with out gravity, you know!thats why you can see old light who is redshifting!Not, because space expanding!space dont expanding or curving/bending at all!.