Scenario #5

[Dillinger]

You are standing on a train going at the speed of light and you walk from the rear of the train to the front.

Would you be going faster than the speed of light relative to the ground?

If so - what happens to you?

 

[cybergirly]

That would depend on rather or not the speed of light is constant.

 

[Ice Cold]

Hmmm,,,, that depended... could they ever build a train that would have the structural integrity to withstand going the speed of light?

 

[Guest]

You are standing on a train going at the speed of light and you walk from the rear of the train to the front.

Would you be going faster than the speed of light relative to the ground?

If so - what happens to you?

Yes.
I gain infinite mass and become my own black hole.

 

[Meltzer]

yes the speed of light is constant. it is 186,ooo miles per second. dont know what would happen though, i guess it would be like normal movement. your body isnt goin faster than light just the vehical you are traveling in.

 

[REDWAVE]

Silly

You silly-- if the train is travelling at the speed of light, it, and everything on it, will be converted into energy.

 

[Guest]

Meltzer:
"yes the speed of light is constant."

It used to be constant, now they have reason to doubt that.

 

[Siren]

 

[Sillyman]

Depends on whether they have doughnuts or not.

 

[Meltzer]

Meltzer:
"yes the speed of light is constant."

It used to be constant, now they have reason to doubt that.

so you're saying that used to be constant but now its not. huh well whatever last time i checked it was constant.

 

[Dillinger]

so you're saying that used to be constant but now its not. huh well whatever last time i checked it was constant.

OH? Where did you last check, may I ask? We can compare sources?

When we walk into a dark room, flip a switch and the light is instantly on, it seems that light has no speed but is somehow infinite - instantly there - and that was the majority opinion of scientists and philosophers until September 1676, when Danish astronomer Olaf Roemer announced to the Paris Academie des Sciences that the anomalous behavior of the eclipse times of Jupiter's inner moon, Io, could be accounted for by a finite speed of light. [2] His work and his report split the scientific community in half, involving strong opinions and discussions for the next fifty years. It was Bradley's independent confirmation of the finite speed of light, published January 1, 1729, which finally ended the opposition. [3] The speed of light was finite-incredibly fast, but finite.

The following question was: "Is the speed of light constant?" Interestingly enough, every time it was measured over the next few hundred years, it seemed to be a little slower than before. This could be explained away, as the first measurements were unbelievably rough compared to the technical accuracy later. It was not that simple, though. When the same person did the same test using the same equipment at a later period in time, the speed was slower. Not much, but slower.

Available measurements of c and several statistical studies suggest that c has decreased in the past 300 years. What other "constants" of physics might prove to be non-fixed? How would a non-constant c affect physical laws?

http://www.ldolphin.org/constc.shtml

"Speed of light may not have been constant after all"
By The Associated Press
August 2001
http://www.usatoday.com/news/healthscience/science/astro/2001-08-15-speed-of-light.htm

New observations from the world's biggest telescope indicate that one of nature's supposedly immutable constants has changed over the 15 billion-year history of the universe.

Physicists were shocked at the discovery, but pleasantly so because it suggests that new theories about how the universe works on the subatomic scale may be correct.

More?

On Thursday 8th August 2002, a burst of Press publicity accompanied the publication of a paper in the prestigious scientific journal Nature. That article was authored by Professor Paul Davies, of Sydney's Macquarie University, and by two astrophysicists from the University of New South Wales, Dr. Charles Lineweaver, and graduate student Tamara Davis. The paper suggested that the speed of light was much higher in the past and had dropped over the lifetime of the universe. These conclusions were reached as a result of the observations of University of New South Wales astronomer Dr. John Webb made in 1999 and the more recent observations of one of his PhD students, Michael Murphy. These observations indicated a slight shift in the position of the dark lines that appear in the rainbow spectrum of metallic atoms deep in space when compared with their expected position.

And more?

The question whether the speed of light is a true physical limit has no definite answer yet. It depends on the real structure of the space-time continuum, which is presently unknown. If absolute time (and a preferred reference frame) exist, then faster-than-light speeds - and even faster-than-light travel - are possible, at least in principle. Although the theory of special relativity states against absolute time and superluminal phenomena, it does it not by proof, but only by assumption.

And by the way... It may be a surprise for many that even within the framework of general relativity faster-than-light speed is allowed, provided that the space-time metric of the universe is globally hyperbolic. This condition simply implies that closed time-like paths in space-time are excluded, so that causality is again preserved. (In this framework, the cosmological time parameter can be interpreted as the absolute time of the universe.)

Additional Resources:

http://homepage.sunrise.ch/homepage/schatzer/space-time.html

http://www******.com/scienceastronomy/generalscience/constant_changing_010815.html

http://www.abc.net.au/lateline/s347215.htm

• I. B. Cohen, "Roemer and the first determination of the velocity of light (1676)," Isis , Vol. 31, pp.327-379, 1939.
• J. Bradley, "A letter", Philosophical Transactions , Vol.35, No. 406, pp.637-661, December 1728.
• R. T. Birge, Reviews of Modern Physics, Vol. 1, January 1929, pp.1-73. See also: http://sunsite.berkeley.edu:
• A. Montgomery and L. Dolphin, Galilean Electrodynamics , Vol. 4 No. 5, pp. 93ff., 1993.
  6. V. S. Troitskii, "Physical Constants and the evolution of the Universe", Astrophysics and Space Science Vol. 139, 1987, pp
  389-411.
• W. G. Tifft, Astrophysical Journal , 206:38-56, 1976; 211:31-46, 1977; 211:377-391, 1977; 221:449-455, 1978;
  221:756-775, 1978; 233:799-808, 1979; 236:70-74, 1980; 257:442-449, 1982; etc.
• T. Beardsley, Scientific American 267:6 (1992), p. 19;. J. Gribbin, New Scientist 9 July (1994), 17; R. Matthews, Science 271
  (1996), 759.
• T. C. Van Flandern, "Precision Measurements and Fundamental Constants II," Taylor and Phillips (Eds.), National Bureau of
  Standards (U.S.) Special Publication 617, 1984, pp. 625-627.
• I. Newton: "Mathematical Principles of natural philosophy", (London, Dawson, 1969)
• J. P. Hsu, L. Hsu: "A physical theory based solely on the first postulate of relativity", Physics Letters A 196 (1994), pgs.1-6; F. Selleri: "Theories equivalent to special relativity", in Frontiers of Fundamental Physics, edited by M. Barone and F.Selleri, (Plenum Press, New York, 1994)
• H. Reichenbach: "The philosophy of space and time", (Dover, New York, 1958)
• J. D. Jackson: "Classical electrodynamics", (Wiley, New York, 1975), chapter 11
• Y. Aharonov, D. Z. Albert: "Can we make sense of the measurement process in relativistic quantum mechanics?", Physical "Relativistic Quantum Measurements", Annals of the New York Academy of Sciences, Volume 755 (1995) ("Fundamental Problems in Quantum Theory"), pgs. 445-450
• A. Einstein, B. Podolsky, N. Rosen: "Can quantum-mechanical description of physical reality be considered complete?", Physical Review 47 (1935), pp. 777
• J. S. Bell: "On the Einstein Podolsky Rosen paradox", Physics 1 (1964), No. 3, pp. 195
• A. Aspect et al.: "Experimental realization of Einstein-Podolsky-Rosen-Bohm gedankenexperiment: A new violation of Bell's inequalities", Physical Review Letters 49 (1982), No. 2, p. 91; "Experimental test of Bell's inequalities using time-varying analyzers", Physical Review Letters 49 (1982), No. 25, pp. 1804
• R. Y. Chiao, P. G. Kwiat, A. M. Steinberg: "Faster than light?", in Scientific American (1993), August
• O. Steinmann: "The EPR Bingo", Helv. Phys. Acta, Vol. 69 (1996), pgs. 702-705
• S. Weinberg: "Gravitation and cosmology", (Wiley, New York, 1972), chapter 14
• C. J. Isham: "Prima Facie Questions in Quantum Gravity": Relativity, Classical and Quantum, eds. J. Ehlers and H. Friedrich, Springer-Verlag, Berlin (1994), e-print:gr-qc/9310031; G. K. Au: "The Quest for Quantum Gravity", e-print:gr-qc/9506001
• B. Nodland, J. P. Ralston: "Indication of Anisotropy in Electromagnetic Propagation over Cosmological Distances", Physical Review Letters 78 (1997), No. 16. 3043-3046; e-print:astro-ph/9704196; see also here
• M. Alcubierre: "The warp drive: hyper-fast travel within general relativity". Classical and Quantum Gravity 11 (1994),pgs. L73-L77, see also here.

 

[calypso_21]

Wow...I'm skipping class today. I've had my lesson for the day. Finally something more interesting than various systems of the body and their functions.

 

[Mountain Man]

Please remember that the speed of light of 186,000miles/second/second...refers to light in a vacume...

light waves and particles are affected by outside forces that affect the speed of it.

light is bent by gravitational forces...ie...stars and Black holes....

 

[Dillinger]

Exactly right, MountainMan. Light also travels at differet speed through various objects, including water.