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Topic: Variable speed of light


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In the News (Fri 17 May 13)

  
 Faster-than-light - Encyclopedia, History, Geography and Biography
In special relativity, while it is impossible to accelerate an object to the speed of light, or for a massive object to move at the speed of light, it is not impossible for an object to exist which always moves faster than light.
For example, fast-moving particles on opposite sides of a circular particle accelerator will appear to be moving at slightly less than twice the speed of light, relative to each other, from the point of view of an observer standing at rest relative to the accelerator, and who naively adds velocities according to Galilean relativity.
In conventional physics, the speed of light in a vacuum is assumed to be a constant.
www.arikah.net /encyclopedia/FTL   (4555 words)

  
 Variable speed of light - Wikipedia, the free encyclopedia
A variable speed of light (VSL) is the idea that the speed of light, usually denoted by c, may not be constant, for some reason.
Paul Davies and collaborators have suggested that it is in principle possible to disentangle which of the dimensionful constants (the elementary charge, Planck's constant, and the speed of light) of which the fine-structure constant is composed is responsible for the variation.
A variable speed of light cosmology has been proposed independently by John Moffat and the two-man team of Andreas Albrecht and João Magueijo to explain the horizon problem of cosmology.
en.wikipedia.org /wiki/Variable_speed_of_light   (1849 words)

  
 SPEED OF SOUND AND LIGHT YEAR DISTANCE | MILES OR KILOMETRES PER HOUR CONVERSION TABLES | SPEED ACE NELSON KRUSCHANDL.   (Site not responding. Last check: 2007-10-20)
This exact speed is a definition, not a measurement, as the metre itself is defined in terms of the speed of light and the second.
According to standard modern physical theory, all electromagnetic radiation, including visible light, propagates (or moves) at a constant speed in a vacuum, commonly known as the speed of light, which is a physical constant denoted as c.
Any slight change in speed of light along each arm of the interferometer (due to the fact that the apparatus was moving with the Earth through the proposed "aether") would change the amount of time that the beam spent in transit, which would then be observed as a change in the pattern of interference.
www.speedace.info /speed_of_sound_and_light_year_distance.htm   (4543 words)

  
 ScienceDaily: Einstein In Need Of Update? Calculations Show The Speed Of Light Might Change
The frequency-dependent expression of the speed of light depends on the gravitational constant, a quantity that is known since Newton established his law of gravitation.
The frequency-dependent expression of the speed of light was used to solve a problem faced by three physicists: Tadashi Kifune, from the University of Tokyo in Japan, Ray Protheroe, from the University of Adelaide in Australia, and Hinrich Meyer, from the University of Wuppertal in Germany.
Speed Of Light May Not Be Constant, Physicist Suggests (October 6, 1999) -- A University of Toronto professor believes that one of the most sacrosanct rules of 20th-century science -- that the speed of light has always been the same - is wrong.
www.sciencedaily.com /releases/2001/02/010212075309.htm   (2196 words)

  
 Speed of light... variable? - SciForums.com
The speed of light in a vacuum is a constant for all observers, regardless of their relative speeds.
Photons may interact with electrons to zig zag and slow the speed of the propagation wave front it may even smear into an atom and form a polariton with a hole (which is what they call stopping light) but light really never travels at other than c when you add all it's properties together.
The postulate in SR concerning light is where Einstein states that the speed of light, c, is constant for all observers.
www.sciforums.com /showthread.php?t=4389   (1649 words)

  
 VSL (Variable Speed of Light) Relativity - Advanced Physics Forums   (Site not responding. Last check: 2007-10-20)
Joao Magueijo asserts in his book, “Faster Than the Speed of Light: The Story of a Scientific Speculation”, Perseus Publishing, 2003, that revisions to special relativity that do not contradict the relativity of motion are possible.
VSL is now an umbrella for many different theories, all predicting, in one way or another, that the speed of light is not constant, and that revisions to special relativity are required.
The only time I\'ve heard the possibility of light not being constant was when they published some results from the background radiation possibly pointing to the fine structure constant not being so constant during the early universe....
www.advancedphysics.org /forum/showthread.php?t=62   (872 words)

  
 Lightspeed versus Special Relativity
The idea that light from a remote source maintains a constant speed (c) relative to all observers regardless of their differing speeds and directions, as proposed by the theory of Special Relativity, is shown to be incompatible with the characteristics of light's speed demonstrated by the data, analysis and charts of Io's eclipse timing.
The speed of light was assumed to be constant in relation to this material Aether of space, in the same manner that the speed of sound is constant relative to its medium.
With the light and the space craft racing to the same point at their different speeds,...how is it possible to subscribe to the concept of Special Relativity (SR) that states that the relative light speed does not decrease with changing motion.
home.netcom.com /~sbyers11/litespd_vs_sr.htm   (6416 words)

  
 Relativity in Quran (Islam)
Is the speed of angels, which we intend to calculate and then compare to the known speed of light (no external forces, no acceleration, no deceleration).
For example, an observer outside gravitational fields measures the speed of light locally (in his location) at 299792.458 km/s but when he looks towards a fl hole he sees the speed of light there to be as slow as a few km/s.
In conclusion, the velocity of light in a gravitational field is not a constant, but rather a variable depending upon the reference frame of the observer; what one observer sees as true another observer sees as false.
www.speed-light.info /relativity_quran.htm   (8806 words)

  
 Varying speed of light a fiber-optics plus?   (Site not responding. Last check: 2007-10-20)
Although there is no known technological application for speeding up light beyond its theoretical limit of approximately 186,000 miles per second, Thevenaz's experiment has generated some controversy, since it appears to violate the basic principle of relativity, which states that nothing in the universe can travel faster than light.
This long-elusive goal of EEs would be enabled by the smooth variation of the speed of light in the fiber, rather than by changing the length of the delay line, which is the ordinary solution.
"The kind of light speed we strongly modified was the 'group velocity' that in textbooks is associated with the speed of the signal.
www.commsdesign.com /printableArticle/?articleID=170700576   (929 words)

  
 Speed of light question - Revisited - Advanced Physics Forums   (Site not responding. Last check: 2007-10-20)
Light isn't subject to combined speed - it always moves at the same rate, no matter what frame of reference you choose.
If you were moving at the speed of light, you wouldn't experience anything, because you wouldn't be moving through time.
Light propagates at C because of the permeability and permittivity of free space and the way electromagnetic waves propagate.
www.advancedphysics.org /forum/showthread.php?t=3512   (734 words)

  
 A Ritzian Interpretation of Variable Stars
This article is written under the presumption that the constancy of the "measured" speed of light by all observers (in vacuo) is an unresolved issue.
in which the velocity of a light source is vectorially additive to the velocity of the light emitted by it, i.e., the velocity of light is c + v.
For example, the light curves in the figure to the left were produced by a computer program which simulates the orbit of one component of a spectroscopic binary.
www.datasync.com /~rsf1/binaries.htm   (1108 words)

  
 Ultra High Energy Cosmic Rays
Using Fox* extinction-limited Ritzian Variable Speed of Light (VSL)** relativity(1)(2)(3), Ultra High Energy Cosmic Rays can be explained as the result of time-wise compression of many cosmic rays, the compression being brought about by close encounters of stars.
Tolman held to the view that the speed of star light was not affected by its passage through the earth's atmosphere.
Light curves for the blue component are shown for increasing distances from the encounter.
www.datasync.com /~rsf1/uhecrs.htm   (1377 words)

  
 The Decay of c-decay
By observing light emitted from a supernova, it can be determined that the speed of light has not changed appreciably in the past 170,000 years.
As Setterfield states, "The basic postulate of this article is that light has slowed down exponentially since the time of creation," making it clear that he intends to show not only a decay in the value of c, but an exponential decay.
In fact, the authors plot a set of residuals against light travel time and state, "The best fit occurs at zero where the light travel time is identical to the currently accepted value value," completely contradicting the value in Setterfield's table.
www.talkorigins.org /faqs/c-decay.html   (2038 words)

  
 Young Earth Argument: Is The Speed Of Light Decreasing ?
Some creationists have claimed that historical measurements of the speed of light ("C") show a decrease of half a percent across the last 300 years.
Barry Setterfield suggested that the speed of light was decreasing.
The idea that light had a finite speed was suggested by Romer (or Roemer) in 1675.
www.don-lindsay-archive.org /creation/speed_of_light.html   (760 words)

  
 Re: VSL (Variable Speed of Light) Relativity
This means if I shine a torch at time t and measure the speed of light I will measure exactly the same speed as if I shine it at another time.
The way the speed of light can vary under normal SR is it having a very small mass which means its speed is not the same as the speed in the Lorentz transformation.
Prev by thread: Re: VSL (Variable Speed of Light) Relativity
www.lns.cornell.edu /spr/2003-08/msg0053344.html   (346 words)

  
 "A crisis in physics." @ Blogcritics.org   (Site not responding. Last check: 2007-10-20)
The speed of light is variable, c'=c+v, where c is the speed of photons relative to the light source and v is the relative speed of the light source and the observer.
The speed of light is constant, c'=c, independent of v, the relative speed of the light source and the observer.
Einstein's false second postulate according to which the speed of light is independent of the speed of the light source should be replaced with its negation: The speed of light does depend on the speed of the light source.
blogcritics.org /archives/2003/10/28/122259.php   (4726 words)

  
 Mailgate: it.scienza: Relatività ed autodistruzione   (Site not responding. Last check: 2007-10-20)
If they undergo acceleration the frequency shift detected by the receiver is due to the variable speed of light, in accordance with the formula c'=Lf', where L is wavelength and f is frequency.
Roughly speaking, either variable speed of light and no gravitational time dilation, or gravitational time dilation and constant speed of light.
Initially Einstein chose c'=Lf': http://www.physlink.com/Education/AskExperts/ae13.cfm : "So, it is absolutely true that the speed of light is _not_ constant in a gravitational field [which, by the equivalence principle, applies as well to accelerating (non-inertial) frames of reference].
mailgate.supereva.com /it/it.scienza/msg264060.html   (345 words)

  
 New theory on light weighs heavily on scientists | csmonitor.com   (Site not responding. Last check: 2007-10-20)
At the heart of Einstein's elegant equation, E=mc2, is the constant speed of light.
No one knows yet whether or not VSL is correct - a colleague told him it stood for "very silly" - but Magueijo claims that all the disdain from his detractors and the fight for publication was worth it.
"Faster Than the Speed of Light" is part science, part biography, and part adventure, a book that takes us behind the closed doors of the intellectual elite and sheds light on the pettiness and brilliance of speculations and theories that ultimately may change our lives and our beliefs.
www.csmonitor.com /2003/0130/p14s03-bogn.html   (966 words)

  
 variable speed of light   (Site not responding. Last check: 2007-10-20)
v = (4/5) c, or four-fifths the speed of light.
So in other words: to fit a 5m car into a 3m garage the car must be travelling at 4/5 the speed of light in a vacuum (relative to the garage).
It we speed up to catch the car, assuming we started out in motion with the car and synchronized our clocks, we would find that the clocks in the frame of the garage have lost time.
www.physicsforums.com /showthread.php?p=94963   (2032 words)

  
 Speed of Light.   (Site not responding. Last check: 2007-10-20)
However, according to Einstein's theory of General Relativity, the speed of light appears to vary with the intensity of the gravitational field.
These measurements show that the velocity of the moon varies considerably (from 3470 km/hr up to 3873 km/hr); which means that the moon accelerates and decelerates continuously.
Well yes it is faster than the speed of light, but the Big Bang itself turned out to be faster than the speed of light!
www.speed-light.info /angels_speed_of_light.htm   (8969 words)

  
 VSL (Variable Speed of Light) Relativity
I've looked at many papers on VSL (Variable Speed of Light) Relativity on the Internet and they are all beyond me. I've asked about VSL at the newsgroup sci.physics.relativity and have never received a specific answer.
What are the transformation equations between "inertial" frames of reference that modify SR and preserve a variable speed of light?
And finally, is there any possibility that VSL justifies the unorthodox "tired light" hypothesis?
www.lns.cornell.edu /spr/2003-08/msg0053056.html   (140 words)

  
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forum.physorg.com /index.php?showtopic=6831   (135 words)

  
 Varying speed of light a fiber-optics plus?   (Site not responding. Last check: 2007-10-20)
Following on from developments at NXP and Freescale, which of the following three companies do you think is most likely to come under private equity control?
09/05/2005 2:00 PM Portland, Ore. - In an experiment at the Ecole Polytechnique Federale de Lausanne, researchers have been able to speed up or slow down light transmitted through an optical fiber with precise control.
Page 2: Varying speed of light a fiber-optics plus?
eetimes.eu /uk/showArticle.jhtml?articleID=170700446   (831 words)

  
 Skil Orbital Variable Speed Site-Light Jigsaw 4580-04 Review at Epinions.com
Skil Orbital Variable Speed Site-Light Jigsaw 4580-04 Review at Epinions.com
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