Re: A mixture of time dilations and constrictions

[pvalev <pvalev@BAS.BG>]

--- Stephen Speicher <sjs@COMPBIO.CALTECH.EDU> wrote:

> [Sorry for the long delay. I have been away at a conference and I
> found it impossible to keep up with my e-mail.]
>
> On Mon, 7 Jul 2003, pvalev wrote:
>
> > --- Stephen Speicher <sjs@COMPBIO.CALTECH.EDU> wrote:
> >
> > > On Tue, 1 Jul 2003, Pentcho Valev wrote:
> > >
> > > > Stephen Speicher wrote:
> > > >
> > > > > I do not know what you have been told on other lists, but
> > > > > special relativity is a geometric theory with the notion
> > > > > of a point-like event as a fundamental concept.  Clocks
> > > > > are idealized to be present at any given event, not as an
> > > > > extended object but as a point-like particle. One can
> > > > > deal with a clock as an extended object in relativity,
> > > > > but such techniques are _vastly_ more complex than
> > > > > standard analysis.
> > > >
> > > > Still let us try.
> > >
> > > No, let us not. There is no point to complex analysis when
> > > there is a lack of understanding and agreement of basic
> > > principles upon which such an analysis is based.
> >
> >
> > Just a question. When a clock is idealized as a point-like
particle,
> > the analysis is standard and simple, as you say above. When one
deals
> > with a clock as an extended object (i.e. with a real clock), the
> > analysis is vastly more complex and we should not discuss it since
> > there is a lack of understanding between us.
>
> No. The lack of understanding I have referred to is your own, in
> regard to the basic concepts of relativity.  To that end I have
> recommended that you carefully read and thoroughly study Taylor
> and Wheeler's "Spacetime Physics," including working out all of
> the exercises therein. This deceptively simple non-technical book
> will give you a good conceptual understanding of the fundamentals
> of the theory.

Your counterargument (essentially, this is the only counterargument
you have advanced so far) deals exclusively with my personal
qualities. I don't mind and even partly agree with you. However the
problems I raise are in fact college problems - in college textbooks,
it is claimed that the two Lorentz equations can be deduced from
Einstein's two axioms, then they are somehow deduced, and then
implications and examples are given. I don't think I move too far
away from this. What is wrong with discussing this stuff? Imagine I
am ashamed by my ignorance and stop discussing special relativity.
Will you ever start this discussion? Is everything OK with the
presentation of SR in textbooks? Here is an example: in some
textbooks, time dilation is deduced before Lorentz transform is
given, and then this time dilation is used as a premise in the
deduction of Lorentz transform. In most textbooks however time
dilation is obtained as a corollary of Lorentz transform. Should such
problems be discussed on this list? If yes, please explain the
difference between the two approaches (otherwise a student could be
confused).

Pentcho