Question on Photons and Gravitons

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The Code
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Question on Photons and Gravitons

Post by The Code » Sun Jan 31, 2010 7:02 pm

Does A Photon, Contain a Graviton?

There are no links, this is from my mind.

How can a Mass less particle, be affected at the speed of light, by Gravity?

Mark
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bystander
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Re: Question on Photons and Gravitons

Post by bystander » Sun Jan 31, 2010 7:16 pm

My guess is no. The photon is an elementary particle and so is the graviton, if it exists.

As to the rest of your question, see here:

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Re: Question on Photons and Gravitons

Post by RJN » Sun Jan 31, 2010 7:40 pm

The photon and graviton are different particles. They interact with matter differently. For example, a photon is much more easily scattered by an electron. They both are effected by gravitational fields similarly, though: they act as any particle moving very near the speed of light. The inherent reason why the photon and graviton interact with particles differently is really unknown and derived from experiment. Trying to reduce this reason to a theoretical framework that has as few assumptions as possible is one of the underlying drivers of string theory. - RJN

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Re: Question on Photons and Gravitons

Post by The Code » Sun Jan 31, 2010 7:58 pm

I do not believe they will find a Graviton. Unless they are talking about a very complex Nothing. A mass Less particle containing a Mathematical % of gravitons. I really do think the very small is as complex as the whole universe. Sorry
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Re: Question on Photons and Gravitons

Post by neufer » Sun Jan 31, 2010 8:10 pm

mark swain wrote:Does A Photon, Contain a Graviton?
RJN wrote:The photon and graviton are different particles. They interact with matter differently. For example, a photon is much more easily scattered by an electron. They both are effected by gravitational fields similarly, though: they act as any particle moving very near the speed of light.
The bending of light by gravity can be interpreted as a photon absorbing a graviton.

Once absorbed, however, the graviton ceases to exist.

(Photons can also emit gravitons.)
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Re: Question on Photons and Gravitons

Post by The Code » Sun Jan 31, 2010 8:45 pm

neufer wrote: The bending of light by gravity can be interpreted as a photon absorbing a graviton.

Once absorbed, however, the graviton ceases to exist.

(Photons can also emit gravitons.)
Off the Record?

If a Mass less particle can be affected by gravity At the speed of light, something we have not discovered is at work. Free roaming gravitons? I Doubt. Something smaller than we can see? But it is something.
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Re: Question on Photons and Gravitons

Post by bystander » Sun Jan 31, 2010 9:18 pm

neufer wrote:The bending of light by gravity can be interpreted as a photon absorbing a graviton.

Once absorbed, however, the graviton ceases to exist.

(Photons can also emit gravitons.)
How does a photon (an elementary particle) absorb and emit gravitons (another elementary particle)? :?

Of course, I've also heard it suggested that the gauge bosons acquire mass by interaction with the Higgs boson.

My confusion is, if the particles are considered elementary, doesn't that mean there are no smaller constituent particles?

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Re: Question on Photons and Gravitons

Post by neufer » Sun Jan 31, 2010 9:36 pm

mark swain wrote:
neufer wrote: The bending of light by gravity can be interpreted as a photon absorbing a graviton.

Once absorbed, however, the graviton ceases to exist.

(Photons can also emit gravitons.)
Off the Record?

If a Mass-less particle can be affected by gravity at the speed of light, something we have not discovered is at work.
Gravity is coupled to the four-momentum
of both matter & radiation
through the stress-energy tensor :

Image

The stress-energy tensor of a source-free electromagnetic field is
Image

where Fμν is the electromagnetic field tensor:
Image
  • Almost ALL tests of General Relativity thus far, e.g.:
    • 1) Gravitational time dilation and frequency shift
      2) Light deflection and gravitational time delay
      3) Gravitational lensing
    involve the interaction of photons with gravitons.
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Re: Question on Photons and Gravitons

Post by The Code » Sun Jan 31, 2010 9:39 pm

bystander wrote:doesn't that mean there are no smaller constituent particles?
There is as much space in the eye of a needle, As space in the whole universe. (apparently)
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Re: Question on Photons and Gravitons

Post by Chris Peterson » Mon Feb 01, 2010 3:44 pm

mark swain wrote:How can a Mass less particle, be affected at the speed of light, by Gravity?
A photon is not a massless particle. A photon has a rest mass of zero, which is a very useful theoretical concept fundamental to understanding it and other particles. But in nature, a photon is never at rest. In every measurable way, it behaves as a particle with mass. This makes sense for multiple reasons. First, it obviously has energy, and anything with positive energy has a mass equivalence. Second, it has momentum. In Newtonian mechanics, that would be defined as P = mass * velocity. In the case of a single particle, a QM definition is used, P = h / lambda. The two momentum values are physically equivalent in terms of mechanical behavior, so possessing momentum is equivalent to possessing mass.

Thus, it becomes perfectly reasonable to expect a photon to be affected by gravity, either using Newtonian mechanics (which does approximately work, but produces a slightly incorrect result), or using GM and relativistic mechanics.
Chris

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