Re: What is LET?

RP wrote:
> Bilge wrote:
> > Martin Hogbin:
> > >
> > >"Bilge" <dubious@xxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
> > >news:slrndtkf64.5j.dubious@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> > >> Martin Hogbin:
> > >> >
> > >> >"dej4" <clujdej@xxxxxxxxx> wrote in message news:1138321586.235441.304020@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> > >> >> Thank you, Martin
> > >> >>
> > >> >> What makes LET indistinguishable from SR? Who decided that? This group?
> > >> >
> > >> >No, the entire physics community. It is a well known fact.
> > >> >Although the term LET is not widely used, Lorentz's theory
> > >> >was well known to physicists. Both theories are result in
> > >> >the same Lorentz transformations (the clue is in the name).
> > >>
> > >> Actually, that isn't true if one insists on absolute simultaneity,
> > >> even in principle.
> > >
> > >It is for all observable quantities in LET. As for unobservable
> > >quantities, I have never seen one on my life.
> >
> > When someone wants to give me his/her definitions which suffice
> > to define absolute simultaneity, I'll point out the observable
> > differences.
>
> In the context of LET, which amounts effectively to different
> interpretation of the Lorentz transform, events that are simultaneous
> wrt an observer in K are indeed also simultaneous wrt an observer in K',
> despite what Tom Roberts seemed to imply. He started out ok, but
> that's all. He knows what he meant to say, but he say what he meant.

Well, it really boils down to "What is LET", doesn't it?

>
> Firstly we have to distinguish between a measuring stick and clock and
> an observer. Wrt an observation made in K' ( using measuring
> instruments that have not been intentionally tampered with since their
> calibration while at rest in K) the events aren't simultaneous, yet wrt
> an observer in K' (a person who believes that K is the master frame)

But he has no reason to think that *is* the master frame,
as you point out later on.

> they are simultaneous. IOW, the measurements that the K' observer obtain
> do not correspond to his knowledge that the events are simultaneous.
> This knowledge in term stems from his acceptance that K is an absolute
> frame, a master frame, and that time as measured in K is absolute for
> every observer, while his own measured time is not absolute. He regards
> these faulty measurements as arising from the fact that his meter sticks
> and clocks have been physically altered in conjunction with their
> acceleration from K to K'.

That is one way to talk about it. Roberts's is another way
to talk about it. Which one of them is LET? Do you have
a definitive reference that says one way or the other, or are
you just guessing?

>
> An important result of this interpretation is that we may chose a given
> inertial frame as master frame, and then by careful monitoring of
> acceleration (perhaps via an accelerometer) we can intentionally
> recalibrate our meter sticks and clocks so that they remain synchronized
> with the clocks in K wrt the observer in K. If we then use these

You would of course have to speed up your clocks as well
as reset them. This would make physics *really* hard to do.

> purposely modified meter sticks and clocks to measure speeds and times
> and displacements wrt our frame, then we can use the Galilean transform
> to obtain accurate predictions, and moreover all observers how
> participate in this conspiracy against SR will also measure as
> simultaneous any events that are simultaneous in K.

Sure, but I predict there'd be a black market out there for
unadjusted meter sticks and clocks. What people would
end up doing is to use their black-market measuring tools,
and (in the rare cases that this would be coerced by some
policy) convert to "real" time via the Lorentz transform. That
would be much easier than tinkering with clocks all the time
and much *much* easier than changing the laws of physics
to be meaningful with those tinkered clocks.

And not just physics. Imagine a doctor trying to take your
pulse, and then looking into some almanac to get the current
speed wrt the master frame, then looking up the pulse
reading (wrt the tinkered clocks) in some giant table to
determine whether that pulse was normal. I think that doc
would soon be getting a clock from the black market too...

>
> Thus space-time is truly Galilean wrt LET. It is however because we
> cannot determine which frame is master frame that we must go ahead and
> use our relativistically altered meter sticks and clocks as is, that is,
> since we don't know which frame with which to sync them, and as a result
> the Lorentz transform, which has these measurement adjustments already
> incorporated into them, is used instead. That is the difference between
> LET and SR. SR doesn't regard the Lorentz transform as just a Galilean
> transform plus necessary conversion factors, bur rather as.....hell I

I don't think LET regards it that way either, if I even know
what you mean by that. Certainly you don't get the
Lorentz transform by multiplying a Galilean transform
by some factor. Or "plussing" some factors either.

> don't know what it regards the Lorentz transform *as* other than a way
> to get the right answer. It is no interpretation at all of the
> transform. :)

The Lorentz transform is a theorem of the SR postulates.

>
> Another way to describe the difference is that it exists only in what
> each system of thought regards as true time and true displacement. One
> is no more correct than the other, it's a simple matter of a priori
> assumptions, that in turn lead to different philosophical positions,
> though the math is completely unaffected. Both of those philosophies
> have a high probability however of being "not even wrong", IMHO. That's
> why I state that the theories underlying these philosophies, since those
> theories are just the maths, are in actuality identical.
>
> There are many mathematical approaches to any problem whatsoever, yet it
> seems only in the LET/SR debate are they ever regarded to express
> different theories. I say farmer Joe has 3 cows because he had two when
> I met him, and then Bessy his cousin gave him another, but Joe took one,
> and then later brought it back. That is my theory of the 3 cows. Now
> you might come along and say well, I say he has 3 cows because I added
> all the legs and there were 12, then I divided by 4 and got 3, and that
> is why he has 3 cows. Your interpretation may differ, but the bottom
> line is that he has 3 cows, how we got there is really immaterial.

So if it doesn't matter, why are you making such a big deal over
what Roberts said?

.

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