So, I was sat on the loo and thought...

In article ,
Mark McIntyre wrote:

Clearly you did not read the caveat underneath that explained how to
make a proper superluminal pair of scissors where the blade crossing
point does move at a speed greater than c.

Clearly, you didn't understand it (and I suspect that whoever wrote it
didn't fully, either, or at least wasn't able to explain to
themselves). The 'length' of such scissors would have to be
infinitesimal. By that stage, other problems will appear.

The scissors can be of normal size with the blades moving at, say,
1 cm / second. If the angle is small enough (which of course it never
is with typical scissors, because of the way they are hinged) then
the crossing point can be made to move at arbitrarily high speeds.

Consider two blades, one moving up the y axis at 1 m/s, the other with
its edge at a very small angle to the x axis, say along the line
y = x / 10^10. Suppose at t=0 the first blade's edge is at y=0, so that
at time t its edge is along the line y = t.

Nothing is accelerating, no forces are acting, nothing physical is
moving at more than 1 m/s. No relativistic mechanics are involved.

The locus of the intersection of the blades is (10^10t, 0).

-- Richard