On May 15, 2:24�am, PD wrote:
On May 14, 11:31�pm, rbwinn wrote:

� � However, it defies all of the laws of physics and mathematics for
a train to shrink to a fraction of its length just because it is
moving.

What laws of physics and mathematics would that be?

In the interest of foreshortening the conversation, note that neither
the Galilean nor Lorentz transforms are laws of physics. Perhaps you
could start by listing a few laws of physics you know, and then select
out of that pool the ones you think are defied by having length be a
frame-dependent quantity.

While you're at it, note that kinetic energy of an object is a frame-
dependent quantity, even in Galilean physics. And note that energy
conservation is one of the laws you're looking for. This would be a
good opportunity to point out also why no laws of physics are violated
by this frame-dependence.

PD

Well, according to Einstein's interpretation of the Lorentz equations,
and also Lorentz's, one frame of reference actually shrinks relative
to the other. Not only that, but the one that shrinks is also its own
size in its own frame of reference, and the other frame of reference
is shrinking. So there are several things going wrong at once here.
Scientists at one time maintained that no laws of science were
violated by the Ptolemaic system of astronomy because it could
accurately predict the positions of planets with its complicated
mathematics of epicycles. Do you know how to figure epicycles?
Well, maybe you had better brush up on them because some
scientists said they were true.
Robert B. Winn