[Phys-L] time dilation, or not

[John Denker <jsd@av8n.com>]

On 04/25/2013 11:49 PM, Dr Keith S Taber wrote:

> What, no time-dilation?

Nope.  Not anymore.

People like to talk about «Einstein’s Special Theory of Relativity (1905)».
However, our understanding of relativity did not begin or end with Einstein, 
and it did not begin or end in 1905.  There were major contributions from 
Galileo, FitzGerald, Lorentz, Poincaré, Michelson, Morley, and many many 
others.

The most original and most consequential contribution was from Minkowski 
(1908).  That's where we get the idea of time as the fourth dimension.
That's where we get spacetime diagrams.

Special relativity is the geometry and trigonometry of spacetime; nothing
more, nothing less.  If you agree that rotating a ruler does not change
"the" length, then boosting a clock does not change "the" time.  The
*projection* onto the laboratory x and/or t axes might get changed, but 
the interesting physics -- the /simple/ physics -- doesn't care about 
the projections.  It cares only about the proper length, the proper 
time, and the invariant mass.  For details, see
  http://www.av8n.com/physics/spacetime-welcome.htm

> (If not, why then has the news been so slow to reach me?)

Theory #1:  It could be a glitch in the matrix.

Theory #2:  There is a tendency for people to assume that whatever Einstein
said in 1905 or 1907 must be the Last Word on the subject ... even when
it comes to things like relativity or the alleged quantization of energy, 
where our understanding has dramatically improved since then.

Einstein relied on Minkowski's ideas for all of his later work ... including 
general relativity.  It's practically impossible to get anywhere with GR 
without the modern (post-1908) approach to SR.

The influential little book _Spacetime Physics_ by Taylor and Wheeler came 
out in 1963.  Both Taylor and Wheeler went on to win Oersted medals.  So 
it's not like any of this is a big secret.