Re: colp, why did AE use the word "relativity"?

On Jun 20, 2:34 pm, "Sue..." <suzysewns...@xxxxxxxxxxxx> wrote:
On Jun 20, 1:57 am, Uncle Ben <b...@xxxxxxxxxxx> wrote:

colp, you complain that SR implies a contradiction: each twin is
younger than the other, which is absurd. No one has yet explained to
you why, in SR, it is not absurd.

Consider two trains passing in opposite directions.. I  am in one
train and you are in the other. I say I am stationary and you are
moving;  you say you are stationary  and I am moving.

We go to a seance and the medium let's us ask the  ghost of Galileo
who is right?  Galileo says, "motion is relative!" We agree then that
we are both right, each relative to his own rest frame of reference.

Consider now the first phase of the symmetric twin puzzle: each twin
calculates from SR that the other is aging slower than himself.
Absurd? No, each is correct relative to his own rest frame.  


Still looking for a book written since 1905?

discovered that time is relative!

No he didn't. He placated the adherents of Newton's
corpuscular light notions by stipulating it
that way and specifically excluding the
physical nature of light.

<<There is only one demand to be made of the
definition of simultaneity, namely, that in
every real case it must supply us with an
empirical decision as to whether or not the
conception that has to be defined is fulfilled.
That my definition satisfies this demand is
indisputable. That light requires the same time
to traverse the path A —> M as for the path B —> M
is in reality neither a supposition nor a hypothesis
about the physical nature of light, but a stipulation
which I can make of my own freewill in order
to arrive at a definition of simultaneity.”>>

You don't want to believe that time is relative,

Perhaps he has cracked a book or two written
after 1918.

<< Application of Noether's theorem allows physicists to
gain powerful insights into any general theory in physics,
by just analyzing the various transformations that would
make the form of the laws involved invariant. For example:

    * the invariance of physical systems with respect
      to spatial translation (in other words, that the laws
      of physics do not vary with locations in space) gives
      the law of conservation of linear momentum;
    * invariance with respect to rotation gives the law
      of conservation of angular momentum;
    * invariance with respect to time translation gives
      the well-known law of conservation of energy  >>

because you have no
experience moving at even 0.001 c, but people have measured the
effect, and Einstein was right.

Was he right in 1905 or right in 1920?

<< Einstein's relativity principle states that:

     All inertial frames are totally equivalent
     for the performance of all physical experiments.

In other words, it is impossible to perform a physical
experiment which differentiates in any fundamental sense
between different inertial frames. By definition, Newton's
laws of motion take the same form in all inertial frames.
Einstein generalized[1] this result in his special theory of
relativity by asserting that all laws of physics take the
same form in all inertial frames. >>

[1]<< the four-dimensional space-time continuum of the
theory of relativity, in its most essential formal
properties, shows a pronounced relationship to the
three-dimensional continuum of Euclidean geometrical space.
In order to give due prominence to this relationship,
however, we must replace the usual time co-ordinate t by
an imaginary magnitude


ct proportional to it. Under these conditions, the
natural laws satisfying the demands of the (special)
theory of relativity assume mathematical forms, in which
the time co-ordinate plays exactly the same rôle as
the three space co-ordinates. >>

<< where epsilon_0 and mu_0 are physical constants which
can be evaluated by performing two simple experiments
which involve measuring the force of attraction between
two fixed charges and two fixed parallel current carrying
wires. According to the relativity principle, these experiments
must yield the same values for epsilon_0 and mu_0 in all
inertial frames. Thus, the speed of light must be the
same in all inertial frames. >>


Uncle Ben- Hide quoted text -

- Show quoted text -

Sue, you haven't lost your touch. In spite of your advanced age, you
still manage to post almost as much irrelevant material as our friend

But I've already read this stuff. Please find something new next
time. How about the Magna Carta, or one of Shakespeare's plays?