On Tue, 17 Jun 2008 04:33:48 -0700 (PDT), Pentcho Valev
wrote:


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

I'd say the solution to this paradox is to distinguish between two
kinds of length contraction as follows:

I. Suppose the bug and its hole are at rest in 3-space and that the
rivet is moving.

Then:

1) In the frame of the bug, the Lorentz transform of the length of the
rivet represents a genuine length contraction.

2) In the frame of the rivet, the Lorentz transform of the depth of
the hole represents only an apparent length contraction--necessary to
keep calculations consistent.

So the bug is safe in this case.

II. Suppose the rivet is at rest in 3-space and the bug and its hole
are moving.

In this case, the situation is reversed and the bug gets squashed.

III. Suppose the bug and rivet are both moving through 3-space.

Then:

1) In the frame of the bug, the Lorentz transform of the length of the
rivet represents a length contraction that is part genuine and part
only apparent.

2) Ditto for the Lorentz transform for the depth of the hole in the
frame of the rivet.

So in this case the outcome would depend on which is moving faster
through 3-space.

I don't see any way to resolve this paradox with the spacetime
concept.


-- Surfer








Pentcho Valev