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kevinrichart
Nov23-09, 10:27 AM
I am new at this so I hope you all will excuse me if I am stupid. But I got this idea about the graviton. If it is a wave then it should display some sort of doppler shift when it moves with respect to the observer.
So there it is , somebody tell me why I am dumb.

DrChinese
Nov23-09, 10:45 AM
But I got this idea about the graviton. If it is a wave then it should display some sort of doppler shift when it moves with respect to the observer.


Welcome to PhysicsForums, kevinrichart!

If the graviton exists (which is an open question), then it is a quantum particle/wave. Photons exhibit a slight frequency shift in the presence of a gravitional field, but I am not sure if gravitons would shift in the presence of a photon or other fields. If it did, it would be extremely small in size. Since gravitons are too weak to be detected individually (assuming they exist), it wouldn't look good for seeing any frequency shift.

Does that answer your question? I am not an expert on graviton theories.

juzzy
Nov23-09, 08:52 PM
if gravity is a wave then it can be described by wave mechanics but no gravity waves have ever been found. The largest detector, which is in Germany, is plagued by interference which cannot be accounted for. However, the frequency range of the interference closely matches predictions relating to the holographic principle, so in their search for gravity they may have unwittingly made a far more fundamental discovery....the pixels of the universe????

Neo_Anderson
Nov23-09, 11:06 PM
I am new at this so I hope you all will excuse me if I am stupid. But I got this idea about the graviton. If it is a wave then it should display some sort of doppler shift when it moves with respect to the observer.
So there it is , somebody tell me why I am dumb.

I'm thinking that the doppler shift for the graviton would be detected through gravitational lensing somehow.

With sounds, the doppler shift is due to compressed soundwave as the train approaches you and expanded soundwave as the train leaves you. With light ("red shift"), the same principle applies, only the lightsource moving closer to you appears more bluish, and after it passes you, will appear more reddish.

The presence of matter (and hence gravity/gravitons) determines the structure of space. Therefore, any disturbance of this space must be accounted for by a disturbance of the graviton wave. For this reason, I'd think that the graviton and gravitational lensing are keenly tied for the purpose of detection.

You know what? After re-reading this post of mine, I find that I'm damn good at mastering the obvious!