Gravitons and the bending of SpaceTime

[Switchy]

Why look for Gravitons when gravity is meant to be the result of the bending of Space Time?
Instead shouldn't one look for something that causes mass to bend spacetime?

Switchy

[sanctus]

I do not know if this is right, but on the spot I would say that gravitons are the things that tell differents fermions that space-time is curved...just like photons are exchanged between electrically charged particles to tell each other that they are charged...

[CHADS]

This is of wiki.....

The Higgs boson is a hypothetical massive scalar elementary particle predicted to exist by the Standard Model of particle physics.
It is the only Standard Model particle not yet observed, but would help explain how otherwise massless elementary particles still manage to construct mass in matter.
In particular, it would explain the difference between the massless photon and the relatively massive W and Z bosons.
Elementary particle masses, and the differences between electromagnetism (caused by the photon) and the weak force (caused by the W and Z bosons), are critical to many aspects of the structure of microscopic (and hence macroscopic) matter; thus, if it exists, the Higgs boson has an enormous effect on the world around us.

Graviton Composition = Elementary particle
Interaction = Gravity

In physics, the graviton is a hypothetical elementary particle that mediates the force of gravity in the framework of quantum field theory. If it exists, the graviton must be massless (because the gravitational force has unlimited range) and must have a spin of 2 (because gravity is a second-rank tensor field.

Gravitons are postulated because of the great success of the quantum field theory (in particular, the Standard Model) at modeling the behavior of all other forces of nature with similar particles:
electromagnetism with the photon,
strong interaction with the gluons,
weak interaction with the W and Z bosons.

" In this framework, the gravitational interaction is mediated by gravitons, instead of being described in terms of curved spacetime as in general relativity. In the classical limit, both approaches give identical results, including Newton's law of gravitation."

[dkv]

In GR there are no forces... All particles move in a straight line in a curved space time.If the particles are in inertial motion(no force) then there is no question of any interaction because motion gets defined by the inertia ... which is a property inherent to the matter.

[sanctus]

So in GR there is no electrical field since there are no forces ??????????????????????????

[dkv]

wait I am not talking about electricmagnetic force.
I am talking about the gravitational forces.
There are no gravitational forces in GR... All objects remain in a state of inertia in the curved space time and they actually travel straight lines.
Gravity manifests due to curvature in space time.

[freeztar]

Originally Posted by dkv

There are no gravitational forces in GR...

Uhhh...What?

All objects remain in a state of inertia in the curved space time and they actually travel straight lines.
Gravity manifests due to curvature in space time.

Perhaps a better way of stating it is that objects traversing the universe travel along geodesics.

[dkv]

What are geodesics ? Geodesics are the smallest possible distance between two points.. which is nothing but a straight line...
There is no force involved becuase the geometry of curved space time accounts for the gravity... Can you have a force inside a geometry ?

[modest]

Originally Posted by dkv

What are geodesics ? Geodesics are the smallest possible distance between two points.. which is nothing but a straight line...
There is no force involved becuase the geometry of curved space time accounts for the gravity... Can you have a force inside a geometry ?

Yes dkv. Switchy's question concerns the differences between general relativity where gravitation is a result of geometry and proposed theories of quantum gravity such as the graviton in superstring theory where gravitation is a force akin to electromagnetism.

While the theories give equivalent results in the classical limit there do seem to be rather big distinguishing factors. Does anyone know how we would expect time dilation as a result of mass without general relativity? I'm not too well versed in quantum mechanics, certainly not theoretical quantum mechanics so I'm not sure...

~modest

[dkv]

Originally Posted by modest

Yes dkv. Switchy's question concerns the differences between general relativity where gravitation is a result of geometry and proposed theories of quantum gravity such as the graviton in superstring theory where gravitation is a force akin to electromagnetism.

While the theories give equivalent results in the classical limit there do seem to be rather big distinguishing factors. Does anyone know how we would expect time dilation as a result of mass without general relativity? I'm not too well versed in quantum mechanics, certainly not theoretical quantum mechanics so I'm not sure...

~modest

The quantum mechanical theories are of gravity are highly speculative...
GR was invented when it was all when known that Force of gravity exists...
And the same GR has explained the Universe for almost 80 years... people still make use of it to conduct experiments..
The central idea of GR is equivalence between curavture of space time and gravity... why do we experience force or why the theory should be believed is a different issue.But GR as originally proposed transfroms away gravity by choosing an inertial frame...
There are many respectable scientists who believe that it is not just a quatum mechanical universe but a mathematical multiverse... i.e every mathematical object actually exists...

The main question was whether gravitons are needed for pure gravitational reasons... the answer is no.