Re: What happened between Newton and Einstein?

On Feb 28, 1:02 pm, "kk" <mr_kurt_kings...@xxxxxxxxx> wrote:
On Feb 27, 2:38 pm, "PD" <TheDraperFam...@xxxxxxxxx> wrote:

On Feb 27, 12:49 pm, "kk" <mr_kurt_kings...@xxxxxxxxx> wrote:
List _one_ "testable implication" that has been
"derived" from Einstein's second postulate (the
one that claims that light's one-way speed from
Point A to Point B in any and all frames is c).

Sure.
From this postulate was directly derived the Lorentz
transforms.

The Lorentz transforms in turn implied that a clock
traveling in a straighter spacetime path would show
a greater time elapsed between two events than a clock
traveling in a less straight spacetime path.

Thanks for giving a sincere, direct and simple answer.
(No sarcasm intended.)

But let's look a little closer.

You are saying that special relativity explicitly
pertains to different ages for twins and triplets,
and to different time readings for clocks in
different frames (for the same two events).

You are also saying that these different ages and
readings are given by Einstein's 2nd postulate.

Re your first claim, I reply that special relativity
(SR) cannot explicitly pertain to intrinsic twin age
differences (or to intrinsic clock differences)
simply because SR refuses to believe in any effect
(i.e., any observable or detectable effect) of actual
or absolute motion through space, and yet such motion
is the only possible cause of the age differences
between twins and triplets.

I'm sorry, I don't see how absolute motion is the *only* possible
cause of the age differences between twins and triplets.

In the case of the twins, A and B, A and B *both agree* that A takes a
straighter path through spacetime than B. However, this in no way
implies anything about absolute motion.


Re your second claim, I reply that since Einstein's
2nd postulate is purely a mere definition (of clock
synchronization), it cannot pertain to anything in
nature.

I completely disagree. The second postulate is an explicit statement
about what will be the result of a measurement of the speed of light,
independent of any state of motion of the source or of the observer.
There is NOTHING in the statement of the second postulate that says
anything about clock synchronization.

Now, it is true *later* that Einstein *uses* that postulate to define
a procedure for clock synchronization, as in implication of the
postulate. However, the postulate is not dependent on clock
synchronization in any way. In fact, using light for clock
synchronization is not even a *requirement*. You can synchronize two
spatially separated clocks by *any* procedure that carries a signal at
the same speed in both directions -- including walking. Einstein just
happened to use light because he had just postulated that it satisfies
this criterion as a usable signal.

Please be sure to stick with what the postulate says and try not to
include *other* things as implicit postulates that aren't really that.


How, then, you may wonder, did SR come to contain
actual (absolute) clock slowing and absolute rod
length contractions (along with actual or absolute
age differences for twins and triplets)?

The answer is extremely simple, but not extremely
well known:

Real clock slowing and real rod shrinkage entered
SR not via Einstein's postulates, but via his
upfront (pre-postulation-era) acceptance of the
Michelson-Morley experiment null result. (Actually,
Einstein simply accepted upfront full round-trip
nullness, which included both the MMx and the KTx,
with the former having rod contraction, and the
latter having clock slowing.)

Actually, if you read the histories of this, Einstein was pretty
steadfast in being unaware of the MMX result. However, he was *quite*
aware of the form of Maxwell's equations, and he was *very* aware of
that factor of c that appeared everywhere in them, and he was
*painfully* aware that no absolute speed appears anywhere in any of
the Newtonian laws of motion and that this fact ensures their
invariance with choice of inertial reference frame. And so he simply
tried to figure out how it is possible that c could appear in
Maxwell's equations and still have those equations be invariant with
choice of inertial reference frame. It was Maxwell's equations that
demanded the invariance of c, not the MMX.


So twin and triplet age differences were given
via experiment prior to SR (as far as Einstein
was concerned), and were not given by his 2nd
postulate (as you seem to think).

However, as I mentioned above, even though SR
implicitly contains intrinsic clock slowing and
intrinsic rod contraction, it still explicitly
denies their existence by denying all meaning
to that which causes them, namely, absolute
motion through space.

Try again.


.

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