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Gamma-ray burst restricts ways to beat Einstein's relativity
Symmetry ^ | Thursday, October 29, 2009 | David Harris

Posted on 10/29/2009 6:58:41 PM PDT by SunkenCiv

When the Fermi team did the calculations, using the most conservative estimates for how astrophysics plays into this, they determined that the mass scale must be at least 1.2 times the Planck mass, and by using reasonable but less conservative assumptions, they derived lower limits on the mass scale of up to 100 times the Planck mass. One way to interpret this is to say that there is no variation of the speed of light coming from any quantum gravity effects at less than 1.2 times the Planck mass. And given that some quantum gravity frameworks predict that effects should be showing up at that point, perhaps those models are simply wrong, and there is no changing speed of light.

There are, however, quite a few caveats. The limit on the mass scale is only true if the quantum gravity effects show up in the simplest possible phenomenology where the time difference is proportional to the energy difference scaled by the quantum gravity mass. Some models suggest that the time difference might be proportional to the square of the energy difference scaled by the quantum gravity mass. That would be a much smaller time difference and not observable in this kind of experiment.

Additionally, other quantum gravity models could still have quantized space-time but wouldn't show an energy-dependent speed of light in this form. Instead, speed might depend on the polarization of the light (called birefringence, like the optical property of calcite crystals which create two images when you look through them). There are other options floating around as well.

To be fair to the claim, though, ruling out the simplest dependence of speed on energy at the expected Planck scale is a significant constraint on future theories of quantum gravity.

(Excerpt) Read more at symmetrymagazine.org ...


TOPICS: Astronomy; Science
KEYWORDS: anisotropy; cosmology; creation; electrogravitics; energy; energypolicy; evolution; fusion; fusionenergy; inflation; intelligentdesign; nuclear; physics; scientism; stringtheory
[the link behind this image leads to an mp4]
In this illustration, one photon (purple) carries a million times the energy of another (yellow). Some theorists predict travel delays for higher-energy photons, which interact more strongly with the proposed frothy nature of space-time. Yet Fermi data on two photons from a gamma-ray burst fail to show this effect, eliminating some approaches to a new theory of gravity. Click for an animation that shows the delay scientists had expected to observe. Credit: NASA/Sonoma State University/Aurore Simonnet

Gamma-ray burst restricts ways to beat Einsteins relativity

1 posted on 10/29/2009 6:58:43 PM PDT by SunkenCiv
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Here’s the Ars Technica I couldn’t use because of copyright restrictions through the failing Conde’ Nast:

http://arst.ch/9dp


2 posted on 10/29/2009 7:00:06 PM PDT by SunkenCiv (https://secure.freerepublic.com/donate/__Since Jan 3, 2004__Profile updated Monday, January 12, 2009)
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To: AdmSmith; bvw; callisto; ckilmer; dandelion; ganeshpuri89; gobucks; KevinDavis; Las Vegas Dave; ...
Quantum gravity site:freerepublic.com
Google

· List topics · post a topic · subscribe · Google ·

3 posted on 10/29/2009 7:01:20 PM PDT by SunkenCiv (https://secure.freerepublic.com/donate/__Since Jan 3, 2004__Profile updated Monday, January 12, 2009)
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To: SunkenCiv
The limit on the mass scale is only true if the quantum gravity effects show up in the simplest possible phenomenology where the time difference is proportional to the energy difference scaled by the quantum gravity mass.

The above cleared it all up for me.

4 posted on 10/29/2009 7:08:25 PM PDT by Recon Dad (SSGT O - 3rd Afghanistan Deployment - Day 9 getting to FOB)
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To: SunkenCiv

5 posted on 10/29/2009 7:25:46 PM PDT by The Comedian (Evil can only succeed if good men don't point at it and laugh.)
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To: The Comedian

That should do it...


6 posted on 10/29/2009 7:31:18 PM PDT by SunkenCiv (https://secure.freerepublic.com/donate/__Since Jan 3, 2004__Profile updated Monday, January 12, 2009)
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To: The Comedian

LOL


7 posted on 10/29/2009 7:32:43 PM PDT by OneWingedShark (Q: Why am I here? A: To do Justly, to love mercy, and to walk humbly with my God.)
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To: SunkenCiv
Some models suggest that the time difference might be
proportional to the square of the energy difference
scaled by the quantum gravity mass

Anyone with even half a brain knows that....

8 posted on 10/29/2009 7:34:56 PM PDT by mikrofon (Calling the Wizard...)
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To: Recon Dad
Snorg Tees

9 posted on 10/29/2009 7:39:18 PM PDT by SunkenCiv (https://secure.freerepublic.com/donate/__Since Jan 3, 2004__Profile updated Monday, January 12, 2009)
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To: SunkenCiv

Makes sense to me.


10 posted on 10/29/2009 7:40:25 PM PDT by oldbill
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To: SunkenCiv

11 posted on 10/29/2009 8:11:54 PM PDT by JoeProBono (A closed mouth gathers no feet)
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To: Recon Dad
The limit on the mass scale is only true if the quantum gravity effects show up in the simplest possible phenomenology where the time difference is proportional to the energy difference scaled by the quantum gravity mass.

" The above cleared it all up for me."

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

The above made my head hurt! :^p

12 posted on 10/29/2009 8:16:49 PM PDT by airborne (I'm from an older generation. When killing the enemy was a good thing!)
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To: SunkenCiv

Sounds a lot like this thread I posted back in June:

Re-Analysis of the Marinov Light-Speed Anisotropy Experiment
http://www.freerepublic.com/focus/f-bloggers/2270920/posts
06/12/2009 11:25:41 PM PDT · by Kevmo · 27 replies · 1,125+ views
arxiv.org ^ | Reginald T. Cahill


13 posted on 10/29/2009 10:14:29 PM PDT by Kevmo (So America gets what America deserves - the destruction of its Constitution. ~Leo Donofrio, 6/1/09)
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To: SunkenCiv

>>>the mass scale must be at least 1.2 times the Planck mass, and by using reasonable but less conservative assumptions, they derived lower limits on the mass scale of up to 100 times the Planck mass.

I was thinking that just the other day. Darn I knew I should have written it down.


14 posted on 10/29/2009 10:43:39 PM PDT by tlb
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To: Kevmo

It looked familiar, but the commie search engine turned up nothing. :’)


15 posted on 10/30/2009 2:38:35 PM PDT by SunkenCiv (https://secure.freerepublic.com/donate/__Since Jan 3, 2004__Profile updated Monday, January 12, 2009)
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To: tlb

:’)


16 posted on 10/30/2009 2:38:41 PM PDT by SunkenCiv (https://secure.freerepublic.com/donate/__Since Jan 3, 2004__Profile updated Monday, January 12, 2009)
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