Wednesday, September 17, 2008

A Quantum Gravity result?

Two weeks ago I asked a question haunting me for some time, on bad astronomy and universe today forum: What is the gravitational field of a photon?

I discovered this forum via the great podcast of Fraser Cain and Dr. Pamela L. Gay: astronomycast.

And the answered I got kind of stunned me. Like Richard said on the forum:
"But believe it or not, exact solutions of high symmetry conditions exist.
One is a plane ElectroMagnetic Wave solution.
Chris Hillman wrote most of those article I think."

It's amazing! There is an exact solution of a pure "Quantum Gravity" question!
And what's more is that it imply that the "gravitational influence" of a quanta of EM field is actually a PLANE in spacetime!
I'm so annoyed I cannot do the math, and spend time fully grasping this result, because it's exactly what I had in mind.
Can the gravitational effect of the petawatt laser (1.25 e15 watts in 0.5 e-12 seconds) in Livermore Laboratory be detected?
That will be a real "Quantum Gravity" experiment no?

NOTES: The rest of the blog express my feelings and has absolutly no scientifical ground!

If Gravity is a Quantum Field of some kind (and I really don't think it is), the photon should "emit" gravitons in all directions. But traveling at the speed of light that will generate a Gravitational shock wave!
My visual solution was: The photon needs to loose influence in the space dimension it is travelling!
The thing is, the photon is already loosing a dimension: Time!
In standard relativity, all observers are equal. The protons inside the LHC have their own point-of-view of the world that is as valid as ours. The thing is, that, as they increase their speed, their internal clock is getting more and more desynchronized with ours. For them, nothing changed (except when they are accelerated), but for us they look like they are living very slowly. This is strongly evident with particles that decay in nanoseconds and keep running in the accelerators for seconds. So, the faster they go, the lazier (for us) they get!
Everything looks good, since all is asymptotic and the protons can never reach the speed of light. But here is my question: What about the life of a photon?
By using the above limit, the photon does not feel time at all.
So, what is the life expectancy of a photon? It can be zero, no?

So what is amazingly beatiful for me in the above solution is that the photon loose one dimension by "merging" time and it's direction of travel!
I love it, it's just Einstein and Maxwell, and no need for vibrating strings and extra dimensions (Actually we just lost one :)!

Now, with a very strong electric field, generating photons that have this anisotropic influence on spacetime... Can we make the "Funiverse" a reality?

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