Re: [Phys-l] Relativity Question (corrected)

[John Denker <jsd@av8n.com>]

On 05/06/2009 12:28 PM, Eric Lane, Lane wrote:

> However irregular it may be, we are couching our development in the
> context of Newtonian space and absolute time. We distinguish between
> a "classical" observation and a "relativistic" one. The first means
> observation of an event datum, or an algebraic expression such as
> momentum, by a physicist present in the originating frame of the
> event, and in near proximity to his clock, that is, Einstein's proper
> time. The relativistic one is an observation of either of those
> quantities in which one or more data did not originate in the
> observer's frame, but must be transformed to his frame from where it
> orignated. That action introduces a signal delay, which is the
> essence of distinction of a relativistic interpretation. Clearly,
> most of the nomenclature, restrictions, and formalism of space-time
> SR will not apply in our approach, and we ask you to bear with us on
> that. For example, we think the question of how long it takes a
> photon to travel from one point in space to another a defin ed
> distance Lo = vT1 away when sent, is quite reasonable.

I'm pretty sure I know what you're trying to do.  I'm somewhat
sympathetic, having undertaken similar efforts from time to time.
It's a developmental phase that people go through.

I can predict how it will turn out.  The main possibilities are:
  a) You re-invent Fitzgerald-Lorentz transformations.
  b) You re-invent Minkowski spacetime.
  c) You invent something that doesn't work, but you don't
   realize it doesn't work, à la Pentcho Valev.
  d) You realize it doesn't work and either give up or cycle
   back to (a) or (b).

I emphasize that outcome (b) is greatly to be preferred.  Read
Taylor & Wheeler and/or
  http://www.av8n.com/physics/spacetime-trig.pdf
  http://www.av8n.com/physics/odometer.pdf

> .... which is the
> essence of distinction of a relativistic interpretation.

Actually in order to make relativity work, in the non-recommended
Fizgerald-Lorentz approach, there are *three* essences:  
 1) time dilatation,
 2) length contraction, and 
 3) breakdown of simultaneity at a distance.
Usually when people set out to "reconcile" relativity with non-
relativistic physics, they overlook item (3).  More rarely they
overlook one of the other items, or multiple items.

I emphasize that if you take the spacetime approach, you almost
don't need to worry about any of that;  the four-dimensional 
trigonometry takes care of it for you.

> Nothing we have obtained changes relativistic results, is not
> proposed as a better way of doing SR, much less trying to replace it.
> It is a pedagogical investigation which explains what SR is.

Strictly speaking, this re-invention phase is *not* a pedagogical 
exercise, because pedagogy refers to teaching young students.  This 
is a larval phase that you go through by yourself, for your own
edification.  Inflicting it on students would be a huge step in the 
wrong direction.

> we use the Lorentz transformation
> also, once, to determine the light transit time between specified
> frames 

That is an unnecessary abuse of the terminology.  Find another
way of saying it.

> Space-time accomodates the unique propogation properties of light,
> through a coordinate system based on the Lorentz transformation, the
> heart of SR, as shown by Einstein.

I wouldn't have said that.  Spacetime was invented by Minkowski.
Einstein was quite disappointed with himself for not inventing it,
but before long he adopted the spacetime approach.  He *had* to, 
in order to make progress on general relativity.

Following in Einstein's footsteps is a waste of time ... but I
don't expect to talk you out of it.  Sometimes people need to
make a mistake in order to see how big of a mistake it is.
Trying to do relativity without spacetime is like trying to 
eat vichyssoise with a fork.  It's a waste of time, especially
given that spoons are readily available. 

I will also warn you that inventing a theory that explains
_part_ of SR is easy but extremely unhelpful.  Don't go there.
That's serious crackpot territory.