Re: special relativity

[Arnulfo Castellanos Moreno <acastell@FISICA.USON.MX>]

 From the electromagnetic theory, the speed of light
must be a constant because "c" appears as a function
of two constants: epsilon_0 and mu_0.

This constants are independent of the reference frame.


Arnulfo Castellanos Moreno



----- Original Message -----
From: "John Mallinckrodt" <ajmallinckro@CSUPOMONA.EDU>
To: <PHYS-L@lists.nau.edu>
Sent: Monday, May 20, 2002 8:48 AM
Subject: Re: special relativity


> On Mon, 20 May 2002, Justin Parke wrote:
>
> > Most textbooks and teachers (at least all that I have seen or
> > known) introduce special relativity by introducing two
> > postulates:
> >
> > 1)  The laws of physics are the same in all reference frames
> >
> > 2)  The speed of light is independent of the speed of the
> > source and the observer.
> >
> > I have always thought that these are redundant.  Isn't 2)
> > implied in 1)?
>
> This is certainly a fair enough question from our current
> perspective.  Statement 2 *is* implied by statement 1 if you
> consider it to be a law of physics.  (Note that the speed of sound
> is NOT independent of the speed of the source and the observer,
> nor is it implied to be so by statement 1.)  At the time Einstein
> proposed the second postulate, it had not been accepted as a law
> of physics.
>
> Perhaps it would be clearer today to write:
>
> 1)  The laws of physics are the same in all reference frames
>
> 2)  One of the laws of physics is that the speed of light is a
>     universal constant.
>
> John Mallinckrodt      mailto:ajm@csupomona.edu
> Cal Poly Pomona          http://www.csupomona.edu/~ajm