Why Einstein Proposed That Speed Of Light Is Invariable....

On May 16, 9:23*pm, Tom Roberts wrote in
sci.physics.relativity:
wrote:
There is no paradox. "The correct solution works like this:

No, it doesn't. You made a very basic mistake. One that's EASY to make
because of the VERY bad gedanken and the impossible assumptions it
makes, including the fact that the rivet does not stop instantaneously
in ANY inertial frame.

In the rivet frame, the end of the rivet reaches the bottom of the
well and crushes the bug because of the shortened depth of the well.

While the rivet is stopping, THERE IS NO "RIVET FRAME" in which the
rivet is at rest.

( The end hits the bottom of the well before the head reaches the top
of the well.)

This simply is not true, as long as one assumes the rivet is perfectly
rigid.

[...]
This works out to about 1.6 cm.

That's the inconsistency in your analysis -- the rivet is now at rest in
the bug frame, but you have it being 1.6 cm long, which is wrong.

Thus the end of the rivet reaches the bottom of the well before it
ever finds out that the head of the rivet has stopped and crushes the
bug."

This is not true.

Considered in the bug frame, the (short) rivet's head hits the wall and
stops. The part of the rivet body immediately ahead of the head stops,
and in the process of doing so, expands (in this frame). then the part
of the rivet immediately ahead of that stops and expands (in this
frame), etc. all the way to the end of the rivet. It should be clear
that in the bug frame the expansion of the rivet while it is stopping is
MONOTONIC, and so the rivet never crushes the bug. Note this has nothing
to do with elastic deformation of the rivet, it's just that different
regions of the rivet stop in the bug frame at different times in the bug
frame.

In the INITIAL rivet frame [#], one finds that the end of the rivet
stops before the head. This seeming violation of causality is due to the
impossible assumption of perfect rigidity. This is a simple consequence
of the previous discussion in the bug frame, transformed to the rivet frame.

* * * * [#] I of course mean the inertial frame of the rivet
* * * * before it begins stopping, and REMAINING in this frame
* * * * until after the rivet is stopped. This is NOT the "rest
* * * * frame of the rivet" while it is stopping.

As I said earlier, assuming perfect rigidity is incompatible with SR. So
the whole gedanken is ridiculous, because it inherently violates SR, and
also because this rivet has a kinetic energy comparable to a small
atomic bomb (!), and cannot possibly stop. In addition, the fact that
there _IS_ no "rivet frame" makes the analysis not elementary.

This does not illustrate any problem with SR. It merely illustrates the
fact that this is a VERY BAD gedanken.

Tom Roberts

A very bad gedanken Roberts Roberts, an awful gedanken indeed:

http://hyperphysics.phy-astr.gsu.edu.../bugrivet.html

Roberts Roberts your atomic bomb argument is so desperate.... You are
not so silly Roberts Roberts you surely have noticed that the bug is
unimportant: "squashing the bug" can be replaced by "contact betwen
the end of the rivet and the bottom of the hole" and then, not so
silly Roberts Roberts, if the proper length of the rivet is very close
to the proper length of the hole, the speed could be much lower than
0.9c.

By the way Roberts Roberts your cleverer brothers in Einstein criminal
cult do not care much about your atomic bomb argument - see:

http://www.people.fas.harvard.edu/~djmorin/book.html
Chapter 11, p. 42, Problem 11.7: "Seeing behind the stick"

The stick hits the wall Roberts Roberts, stops and....nothing. No
atomic explosion.

Pentcho Valev