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Article #16157

Re: Why sound needs a medium to travel and light not?

#16157
From: Pentcho Valev
Date: Mon, 19 May 2008 23:13
56 lines
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On May 19, 9:14 pm, Sanny <softta...@hotmail.com> wrote:
> > > Why sound needs a medium to travel and light not?
>
> > Why kites need a medium to travel and bullets not?
>
> Good Analogy !!!
>
> Because Kites uses Aerodynamics to fly in air. It uses Air Lift to
> rise high. Bullets travel using the Kinetic Energy possesed by it.
>
> Does Light has a Kinetic Energy that make it fly without the need of
> any Medium?
>
> Bye
> Sanny

A very clever apostle of Einstein's, Banesh Hoffmann, could be useful:

http://www.amazon.com/Relativity-Its-Roots-Banesh-Hoffmann/dp/0486406768
"Relativity and Its Roots" by Banesh Hoffmann, Chapter 5.
(I do not have the text in English so I am giving it in French)
Banesh Hoffmann, "La relativite, histoire d'une grande idee", Pour la
Science, Paris, 1999, p. 112:
"De plus, si l'on admet que la lumiere est constituee de particules,
comme Einstein l'avait suggere dans son premier article, 13 semaines
plus tot, le second principe parait absurde: une pierre jetee d'un
train qui roule tres vite fait bien plus de degats que si on la jette
d'un train a l'arret. Or, d'apres Einstein, la vitesse d'une certaine
particule ne serait pas independante du mouvement du corps qui l'emet!
Si nous considerons que la lumiere est composee de particules qui
obeissent aux lois de Newton, ces particules se conformeront a la
relativite newtonienne. Dans ce cas, il n'est pas necessaire de
recourir a la contraction des longueurs, au temps local ou a la
transformation de Lorentz pour expliquer l'echec de l'experience de
Michelson-Morley. Einstein, comme nous l'avons vu, resista cependant a
la tentation d'expliquer ces echecs a l'aide des idees newtoniennes,
simples et familieres. Il introduisit son second postulat, plus ou
moins evident lorsqu'on pensait en termes d'ondes dans l'ether."

Translation from French: "Moreover, if one admits that light consists
of particles, as Einstein had suggested in his first paper, 13 weeks
earlier, the second principle seems absurd: a stone thrown from a fast-
moving train causes much more damage than one thrown from a train at
rest. Now, according to Einstein, the speed of a particle would not be
independent of the state of motion of the emitting body! If we
consider light as composed of particles that obey Newton's laws, those
particles would conform to Newtonian relativity. In this case, it is
not necessary to resort to length contration, local time and Lorentz
transformations in explaining the negative result of the Michelson-
Morley experiment. Einstein however, as we have seen, resisted the
temptation to explain the negative result in terms of Newton's ideas,
simple and familiar. He introduced his second postulate, more or less
evident as one thinks in terms of waves in aether."

Pentcho Valev
pvalev@yahoo.com
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From: Pentcho Valev <pvalev@yahoo.com>
Newsgroups: sci.physics,alt.philosophy,alt.astronomy,sci.physics.relativity,fr.sci.physique
Subject: Re: Why sound needs a medium to travel and light not?
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