Re: Difference between predictions of SR and LET - perhaps!

Paul B. Andersen wrote:
John Kennaugh wrote:
The following thoughts have come to me and I would like others opinions.
Lorentz's theory - The function of the aether was not merely a medium
in which light waves propagated it was also responsible for 'fields'. A
field maps out an altered state in the aether analogous to a stress
pattern. Forces between charges are transferred due to the interaction
of those 'stress patterns'.
Put simply action at a distance force is transferred via the aether.
Lorentz made the assumption that an object is a matrix of charged
particles held together with action at a distance force - transferred
via the aether.
Q - What then happens if that aether is in motion w.r.t the object?
A- Lorentz worked it out and showed that an object - a ruler say or the
arm of the MMX apparatus - would get shorter in the direction of motion
by the factor gamma thus explaining the null result of the MMX in terms
of Maxwell's aether. Unfortunately it has got into the literature that
Lorentz's 'length contraction' was an ad-hoc assumption.

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The twin paradox of SR - Essentially the 'tick' of a clock is an event.
It either happens or it doesn't. Both the earth bound twin and the
travelling twin agree as to the number of ticks the travelling twin's
clock registers. The earthbound twin sees the time interval between
ticks extended by gamma, as each is longer the travelling clock
registers fewer than his own. The travelling twin on the other hand sees
the distance to the star as contracted by gamma so it doesn't take him
as long to do the trip as it would if it was the distance measure by the
earth bound twin.
They get the same number of ticks but the description of why differs.
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It seems to me that there is a difference between the two theories which
may not be obvious from the maths. As far as I can see Lorentz's length
contraction ONLY applies to solid objects held together with action at a
distance EM forces not to the separation of objects in space. I can't
see as reason why according to Lorentz's theory the travelling twin
would see the distance to the distant star to be shortened.

The two theories will always predict _exactly_ the same for what
will be measured.

Sure the explanations are different, but that's metaphysics.

Not really. Lorentz gives a plausible physical explanation while SR puts forward no specific hypothesis. SR gives no explanation merely a predicted result.


And the LET can't really explain anything.
For example:
I measure the length of a moving metre stick to be shorter
than my metre stick. Why?
1. Because I am stationary in the ether, so the stick is moving
in the ether and is contracted.
2. Because the stick is stationary in the ether and is not contracted,
so I am moving in the ether and my stick is contracted.
However, due to the relativity of simultaneity, I will compare
the ends of the sticks at different times (as measured in the ether frame),
and will still measure the moving stick to be shorter than mine, even
if it in reality is the other way around.
3. Because neither I nor the stick are stationary in the ether, so it is
a bit of 1. and 2., but we can't know how much of each.

So how does LET explain why a moving stick is measured to be shorter? :-)

OK I hadn't thought that through.



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Suppose we have two points X and Y with a row of rulers AA' BB' CC'
measuring the distance between
XA------------A'B------------B'C------------C'Y
Then relativity says if the same set up moves w.r.t the observer it will
contract thus:
XA----------A'B----------B'C----------C'Y
Does LET predict the same or is the following consistent with LET?
X A----------A' B----------B' C----------C' Y

LET and SR always predicts exactly the same for everything!


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If a burst of charged particles is accelerated in a particle accelerator
does the length of the burst tend to zero as the speed approaches c?

No. Do think it should? If so, why?

It would appear to be the same scenario as in the twin paradox. In that the earth and the distant star were moving relative to the travelling twin and the distance between appeared shorter.
In this case the distance between the front particles and the rear particles of the burst might expect to appears smaller the faster they are going relative to a stationary observer. Assuming they are all travelling at the same speed. I don't see a fundamental difference other than in scale and that particles can be accelerated close to c accentuating the effect.


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Finally if SR says that length contraction applies to the separation of
things not merely the dimensions of the things themselves how can there
ever be measurable separation between light pulses? Their FoR is
travelling at c w.r.t us so all distance must contract to zero.

Strange misconception.
If I measure the separation between two light pulses emitted from
a source with one nanosecond interval, I will measure it to be 0.3 metres.
Why do you think the separation should be immeasurable small?

It must have been infinite in the FoR of the light for it appear to be 0.3m in your FoR surely.


There is no such thing as 'the FoR of a light pulse', and even if it were,
we could never measure anything in this FoR anyway.


--
John Kennaugh

.

Relevant Pages

  • Re: Lorentz chose one of three incorrect solutions for MMX
    ... >>>that there is no obvious or demonstrated reason that contraction occurs ... >> If you take the twin paradox and assume that the stay at home twin sees ... >> distance to the distant star is contracted to half the distance the stay ... >> John Kennaugh ...
    (sci.physics.relativity)
  • Re: Difference between predictions of SR and LET - perhaps!
    ... Lorentz's theory -  The function of the aether was not merely a medium ... Put simply action at a distance force is transferred via the aether. ... The twin paradox of SR - Essentially the 'tick' of a clock is an event. ... travelling twin agree as to the number of ticks the travelling twin's ...
    (sci.physics.relativity)
  • Re: Lorentz chose one of three incorrect solutions for MMX
    ... >that there is no obvious or demonstrated reason that contraction occurs ... If you take the twin paradox and assume that the stay at home twin sees ... distance to the distant star is contracted to half the distance the stay ... In the above if you apply expansion in the orthogonal direction it does not contract the distance to the distant star so you could not make the number of ticks the same for both observers. ...
    (sci.physics.relativity)
  • Re: Difference between predictions of SR and LET - perhaps!
    ... Lorentz's theory - The function of the aether was not merely a medium ... Put simply action at a distance force is transferred via the aether. ... Lorentz's 'length contraction' was an ad-hoc assumption. ... The twin paradox of SR - Essentially the 'tick' of a clock is an event. ...
    (sci.physics.relativity)
  • Re: Difference between predictions of SR and LET - perhaps!
    ... Lorentz's theory - The function of the aether was not merely a medium ... Put simply action at a distance force is transferred via the aether. ... Lorentz's 'length contraction' was an ad-hoc assumption. ... The twin paradox of SR - Essentially the 'tick' of a clock is an event. ...
    (sci.physics.relativity)
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