Einstein makes extra dimensions TOE the line

In summary: Have a look:In summary, scientists say that Albert Einstein's principle of the constancy of the speed of light holds up under extremely tight scrutiny, a finding that rules out certain theories predicting extra dimensions and a "frothy" fabric of space.
  • #1
Ivan Seeking
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Scientists say that Albert Einstein's principle of the constancy of the speed of light holds up under extremely tight scrutiny, a finding that rules out certain theories predicting extra dimensions and a "frothy" fabric of space.

http://www.gsfc.nasa.gov/topstory/2003/1212einstein.html [Broken]
 
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  • #2
What I want to know is why are those two black hole particle beams "aimed directly at the Earth"? Coincidence? I think not...
 
  • #3
That's funny, but maybe you should take a look at this,

http://xxx.lanl.gov/abs/astro-ph/0308214

"Some models with large extra dimensions are ruled out by the existence of absorption in the very high energy spectra of nearby BL Lac objects. The fact that more distant brighter sources are not seen can also be taken as indirect evidence of intergalactic absorption by pair production interactions. The constraints based on analysis of the Crab Nebula γ-ray spectrum, discussed in the previous section, imply that the quantum gravity scale is orders of magnitude above the Planck mass scale. This indicates that the class of models considered here with linear Planck scale suppressed terms in the dispersion relations cannot be reflective of physics at the Planck scale. Models such as loop quantum gravity with a preferred inertial frame are ruled out by this line of reasoning. Alternative models to consider might be models with quartic momentum terms with [itex]M_{QG}^2[/itex] supression in the dispersion relations, Lorentz invariant quantum gravity models, or really new Planck scale physics such as string theory, which preserves Lorentz invariance."
 
  • #4
Originally posted by selfAdjoint
What I want to know is why are those two black hole particle beams "aimed directly at the Earth"? Coincidence? I think not...
Ah blazars! They're really no different from other active galactic nuclei (AGNs), just that by chance we're looking straight down the jets. You can use data on the observed blazar sky density to do several consistency checks of AGN models; e.g. if the jets have an opening angle of x radians, then the sky density of AGNs should be [tex]\frac{4\pi}{x}[/tex].

A good collection of links:
http://wwwospg.pg.infn.it/blazarsintheweb.htm [Broken]

BTW, there are several threads with related discussions (including reference to the very same Stecker paper) in our very own PF Special & General Relativity board.
 
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1. What is "Einstein makes extra dimensions TOE the line"?

"Einstein makes extra dimensions TOE the line" is a phrase that refers to the concept of a theory of everything (TOE) that incorporates the idea of extra dimensions, which was first introduced by Albert Einstein in his theory of general relativity.

2. What are extra dimensions?

Extra dimensions are additional spatial dimensions beyond the three dimensions (length, width, and height) that we are familiar with in our everyday lives. These dimensions are theorized to exist at a microscopic level and play a role in unifying the laws of physics.

3. How does Einstein's theory of general relativity relate to extra dimensions?

Einstein's theory of general relativity provides the mathematical framework for understanding the effects of gravity, including the possibility of extra dimensions. It suggests that space and time are intertwined and can be bent or curved by the presence of matter and energy, which could explain the existence of extra dimensions.

4. Why is it important to study extra dimensions?

Studying extra dimensions is important because it could potentially lead to a unified theory of physics that explains all the fundamental forces and particles in the universe. It may also help us understand the mysteries of dark matter and dark energy, which make up the majority of the universe.

5. Has the existence of extra dimensions been proven?

No, the existence of extra dimensions has not been proven yet. It is still a theoretical concept and scientists are conducting experiments and observations to gather evidence for their existence. However, some theories, such as string theory, suggest that extra dimensions may be necessary for a complete understanding of the universe.

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