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Experimental verification of the relativity theory



John Mallinckrodt wrote:

Two events ("light enters train" and "light leaves train") happen
that are identifiable in either frame (otherwise any such analysis
should be abandoned) and we are to compare the distances between
them, x and x', and the time intervals between them, t and t'. I
think the only reasonable criticism of my solution should consist in
offering a solution proving that x/t = x'/t'. Einstein's theory is
expected to be able to resolve problems as simple as
this one.

I disagree. It is not Einstein's THEORY that addresses this
"problem" so much as the primary postulate OF that theory. If "the
speed of light is the same in all reference frames," then x/t =
x'/t'. That is REALLY all there is to it.

It is the spectacular agreement of the many seemingly bizarre
predictions of this theory with every experiment that has been
performed that give us such enormous confidence in the primary
postulate.

Here I am really incompetent - I don't know of those spectacular
agreements - but I have a bad suspicion, judging from what I know about
an analogous problem in thermodynamics. Sorry but I think that, since
Einstein badly needed Lorentz equations, he simply "obtained" them in a
way so absurd that
the world was paralysed and excited at the same time. The same event had
already happened in thermodynamics. In 1824, Carnot published essentially
the following argument:

Heat is an indestructible substance (calorique).
Perpetuum mobile (of the first kind) is impossible.
Therefore, all reversible machines working between two given temperatures
have the SAME efficiency.

Carnot's argument was valid (the conclusion did follow from the premises)
and the
conclusion seemed extremely fruitful - Kelvin quickly converted it into
his famous
universal temperature scale whereas Clausius extracted the concept of
entropy from it.
Then, to Clausius and Kelvin's horror, the fist premise proved wrong -
heat was not an
indestructible substance - the Carnot machine converted it into work. So
Clausius and
Kelvin had to "obtain" Carnot's conclusion in some other way, and this
way was paralysing and exciting at the same time. Nothing new under the
sun.
Curiously, thermodynamicists' dearest quotation belongs to Einstein:
"Thermodynamics is the only physical theory of a general nature of which
I am convinced
that it will never be overthrown". This must have been a spell - I am
sure Einstein cared
more about his own theory which had been based on similar logical tricks.
Tied down by the spell (he probably hoped), scientists would never
decipher thermodynamics' tricks -
likewise Einstein's own theory would never be overthrown.
Now to the point: Carnot's conclusion was in fact the original version of
the second law of thermodynamics. Clausius and Kelvin invalidly deduced
it from

Heat cannot move from a cold to a hot body in the absence of other
associated changes

which is an experience of mankind and which was declared as the "final"
second law. As an experience of mankind, the above statement has
obviously been tested countless tiimes and, in your terminology, the
agreement is spectacular. But the original version of the second law -
Carnot's conclusion - has practically never been tested (except perhaps
for a few not very serious attempts to build perpetuum mobile of the
second kind). When asked, scientists don't even know how it could be
tested.

Pentcho