This animation is based on a section of the (forthcoming) book,
SPECIAL RELATIVITY ILLUSTRATED, by John de Pillis.
At rest, the left surfaces of parallel plates and the length of a rivet shank are both d.
After separation, the rivet travels from the left toward the plates at a speed of 0.8c.
where a bug waits on the righthand plate.
FROM the PLATES FRAME:
The static plates "see" the moving rivet with a shank
that is only 0.6 times its original length. Hence, at the moment of collision, the too-short
rivet shank will not touch the bug.
FROM the RIVET FRAME:
The static rivet "sees" the moving plates with a space between them
that is only 0.6 times its original space. Hence, at the moment of collision, the too-long rivet shank,
relative to the shortened plate space, will touch the bug.
Is the bug touched by the rivet?
Yes --- before the collision in one frame and after the collision in the other
frame! In fact, special relativity
requires that after collision, the rivet shank length increases
beyond its at-rest length d.
To require rigidity and to reject "rivet-stretching,"
is to accept the fact that the future affects the present.