🚀 go-pugleaf

::  = Wolfgang G. Gasser in news:ep6cfd$3uk$1@atlas.ip-plus.net :
:   = harry in news:1169630995_1932@sicinfo3.epfl.ch :

Harry:
:::   dx' = dx/gamma  (a moving rod appears to contract; thus a really
:::                    moving rod really contracts)

Wolfgang:
:: Here also you are a victim of the confusion (resp. fatal error) I'm
:: dealing with. According to SR,  dx' = dx/gamma  means contraction
:: of rest-frame distances wrt the moving frame.

Harry:
: dx = dx'/gamma is valid in S' only. It's an often made mistake ...

Should this be a con trick in order to obfuscate your error above,
or are you simply confusing dx with dx'?

Your just introduced version dx = dx'/gamma actually has the meaning
you by mistake first attributed to dx' = dx/gamma: a moving rod
contracts wrt to the rest frame.

This new version dx = dx'/gamma is valid if we assume simultaneity
in the rest frame S, i.e. dt = 0:

  dx' = gamma * (dx - v*dt)   -->   dx' = dx  * gamma
                              -->   dx  = dx' / gamma

However, the version we originally have been dealing with,
dx' = dx/gamma, implies simultaneity in S', i.e. dt' = 0:

  dx = gamma * (dx' + v*dt')  -->   dx  = dx' * gamma
                              -->   dx' = dx  / gamma

So S-simultaneity leads to contraction of S' wrt S (or expansion of S
wrt S') and S'-simultaneity to contraction of S wrt S' (or expansion
of S' wrt S).

:: An ether distance of e.g. dx = 1 light-year is contracted to
:: dx' = l LY / gamma  in the moving-frame.
:
: "ether" and "is contracted" are incompatible,

and Lorentz ether theory is therefore inconsistent.

Let us assume a twin-paradox situation where one twin remains at rest
in the ether whereas the other travels with v = 0.5 c to a point 1 LY
away from the twin at rest. So an ether distance dx = l LY is passed
in dt = 2 years.

From time dilation follows that the moving twin does not need 2 years
proper time to reach the destination but only dt' = 2 Yr / gamma. So,
if the ether-distance dx from the twin at rest to the destination is
identical wrt the moving twin (i.e. dx' = dx = 1 LY) we get wrt the
moving twin a proper speed of:

   v'  =  dx' / dt'  =  dx / (dt/gamma)  =  v * gamma.

The only way to get a moving-twin speed of v' = v is the assumption,
that the ether distance dx = 1 LY contracts by gamma wrt the moving
twin:

  dx' = dx/gamma   -->   dx'/dt' = (dx/gamma) / (dt/gamma) = v

Time dilation is time expansion. If we combine time dilation with
length contraction, then velocity as length divided by time obviously
cannot remain invariant. Therefore we must combine time dilation of
a moving object with with length expansion of the object (equivalent
to contraction of the rest frame).

: I think that [] you misunderstand what the author of mathpages wrote.

Try again: news:ep2hvi$qli$1@atlas.ip-plus.net

Interestingly the LET-SR confusion, we are dealing with, shows up as
a different incarnation in the article you've pointed to. There you
write:

  "Similarly, the clocks will tick at 3/5 of the rate in rest, making
   one tick 0.6 s of duration. Because this is determined relative to
   the stationary ether or absolute space, the effects correspond to
   physical reality."
http://groups.google.com/group/sci.physics.relativity/msg/9db6b5df54b79f1d

If the clock rate of a moving clock is 3/5 of the rate of rest-frame
clocks, then one moving-clock cycle does not result in 0.6 sec in the
rest frame, but in 5/3 sec. Imagine simply a transversal light clock
moving at v = 0.8 c wrt the ether.

Sorry, Wolfgang