Speed of Light Remains Constant

In summary: Thanks.In summary, NASA has announced results from examining light from two nearby galaxies, Mkn 421 and Mkn 501, which show that the speed of light is consistent with that described by special relativity. This supports the idea of continuous space-time and disproves theories that suggest the speed of light may vary due to quantum foam or extra dimensions. This information is useful in refuting claims that the infinite traversal of time is impossible, and provides further evidence for the existence of the continuum in reality. Additionally, a paper by Stecker discusses how this observation can be used to constrain models with preferred frames and Lorentz invariance violations at high energy. Further research is needed in this area, but
  • #1
Jeebus
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Despite some recent studies that indicate the speed of light may have been slowing down, NASA has announced results of examination of light from two nearby galaxies showing that the speed of light is as special relativity describes it.
Specifically, they looked at Mkn 421 and Mkn 501, both of which have massive black holes spewing gamma radiation. The gamma photons collide with infrared photons and annihilate each other. If the speed of light were not constant, the photons from the galaxies would not have enough energy to cancel out the infrared ones.

There has been some investigation into whether or not the quantum foam would impeded the speed of light. It also brings into question some models of a theory of everything involving extra dimensions. The results indicate that the energy levels of these dimensions can't be as powerful as some of the models claim them to be.

http://www.space.com/scienceastronomy/lightspeed_031217.html [Broken]

and for additional information


http://www.space.com/scienceastronomy/quantum_bits_030402.html [Broken]

These observations are also interesting because they support the idea of continuous space-time as opposed to discrete, quantized space-time. The information is useful in combatting apologetics which claim traversal of an infinite set of temporal moments is impossible, i.e. therefore there must be a First Cause. Not that the contrary can't already be demonstrated using convergent series, but it helps to show that the continuum appears to exist in reality.
 
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  • #2
Good post, I am going to move this to Relativity. There are several posting over there that need to see this.
 
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so is this most profound observation going to change
theorists minds about quantum gravity or the existence
of Planck units or strings and multiple dimentions?
i doubt it, i expect many pages of endless calculations
to show why light can escape any perturbance from
the quantum effect, and the theories will remain
afloat until all the patches are exhausted.
 
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  • #5
If you google on Stecker and arXiv, you'll see that he's active in the field of high energy astronomy, particularly cosmic (gamma) rays.

I've only skimmed a couple of the papers, but found this review to be quite interesting:
http://xxx.arxiv.cornell.edu/PS_cache/astro-ph/pdf/0309/0309027.pdf [Broken]

It isn't immediately obvious which of the papers in arXiv is the one referred to in the space.com article that Jeebus has a link to, but it would be an interesting read too.
wolfram wrote: so is this most profound observation going to change theorists minds about quantum gravity or the existence of Planck units or strings and multiple dimentions?
i doubt it, i expect many pages of endless calculations to show why light can escape any perturbance from the quantum effect, and the theories will remain afloat until all the patches are exhausted.
IMHO, it's just another piece of good research which constrains some models a bit more; part of the on-going effort. A long way to go yet I expect before we're at even the stage we were with neutrinos two decades ago.
 
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  • #6
Found it!
http://xxx.lanl.gov/abs/astro-ph/0308214
"Constraints on Lorentz Invariance Violating Quantum Gravity and Large Extra Dimensions Models using High Energy Gamma Ray Observations"

Comments from people who read this paper are most welcome.
 
  • #7
Originally posted by Nereid
Found it!
http://xxx.lanl.gov/abs/astro-ph/0308214
"Constraints on Lorentz Invariance Violating Quantum Gravity and Large Extra Dimensions Models using High Energy Gamma Ray Observations"

Comments from people who read this paper are most welcome.

this seems like a good paper and Stecker seems very on top of it.
Notice what he says on page 6:

"In many of these models Lorentz invariance is predicted to be violated at high energy. This results in interesting modifications of particle physics that are accesible to observational tests using TeV gamma-ray telescopes and cosmic ray detectors.

An example of such a model is a quantum gravity model with a
preferred inertial frame given by the cosmological rest frame of the cosmic microwave background radiation (For an extensive discussion, see the review given in Ref. [23].)"

I assume what he means by "violating Lorentz invariance"
is having a preferred frame, and what he is constraining (if they have not already been completely eliminated!) are the models in which there is a preferred frame.

To be sure about this, it might be helpful to consult the "review given in Ref. [23]" which Stecker offers as providing "an extensive discussion".
Particularly pages 18 and 19 in that reference: section 4 "The near term experimental situation"

Here is the Ref. [23] link. Any comments?
http://arxiv.org/hep-th/0303185 [Broken]
 
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  • #8
Originally posted by Jeebus
Speed of Light Remains Constant

Doesn’t this study just mean that the speed of light today is the same basic speed as it was half a billion years ago? I doesn’t mean that the relative speed of light never varies when it moves from one object to another. When passing near the sun, a beam of light slows down when viewed from the Earth and measured by an atomic clock at the earth. This was explained in Einstein’s 1911 gravitational redshift theory.
 
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Originally posted by David
Doesn’t this study just mean that the speed of light today is the same basic speed as it was half a billion years ago? I doesn’t mean that the relative speed of light never varies when it moves from one object to another. When passing near the sun, a beam of light slows down when viewed from the Earth and measured by an atomic clock at the earth. This was explained in Einstein’s 1911 gravitational redshift theory.
I don't know much about Einstein's 1911 Gravitational Redshift Theory, so that might account for the reason why I don't fully understand "a beam of light slows down when viewed from earth". I thought Special Relativity described how the speed of light remained constant regardless of your intertial frame (i.e. Its not possible to observe the speed of light "slowing down").

Edit to add: Nevermind, I found the information you were referring to on another thread :)
 
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What is the speed of light and why does it remain constant?

The speed of light is the fastest possible speed at which energy and information can travel through space. It is approximately 299,792,458 meters per second in a vacuum. The speed of light remains constant because it is a fundamental constant of the universe, and it is a result of the relationship between electric and magnetic fields.

How was the constant speed of light discovered?

The constant speed of light was first discovered by Danish astronomer Ole Rømer in the 17th century. He observed that the timing of eclipses of Jupiter's moons varied depending on the distance between Earth and Jupiter, and he realized that this was due to the finite speed of light.

Is the speed of light truly constant in all situations?

According to Einstein's theory of relativity, the speed of light is constant in all reference frames and cannot be exceeded. However, it can be slowed down in certain mediums, such as water or glass, due to interactions with atoms and molecules.

How does the constant speed of light affect our understanding of the universe?

The constant speed of light is a fundamental principle in physics and has led to many important discoveries and theories, such as special relativity and the famous equation E=mc^2. It also plays a crucial role in our understanding of the vastness and age of the universe.

Are there any exceptions to the constant speed of light?

While the constant speed of light is a well-established principle, there are some theories that suggest there may be exceptions in certain extreme scenarios, such as near black holes or during the early moments of the Big Bang. However, further research and evidence are needed to confirm these exceptions.

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