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From: jay@npois.UUCP (Anton Winteroak)
Newsgroups: net.physics
Subject: re long scissors
Message-ID: <334@npois.UUCP>
Date: Wed, 5-Jun-85 14:50:19 EDT
Article-I.D.: npois.334
Posted: Wed Jun  5 14:50:19 1985
Date-Received: Mon, 10-Jun-85 00:30:01 EDT
Organization: ATTIS, Neptune, NJ
Lines: 20


	A way to look at the long scissors experiment to demonstrate
to yourself that you cannot use them to transmit information at faster than
the speed of light (in a vacuum) is that one bar of the scissor can be
held stationary, while the other moves. The moving bar must be waved back
and forth in a way that represents the information being sent. The stresses
in the bar which cause each succeeding layer of atom to sway one way
or the other cannot move faster than the speed of light.
	Of course if you are only looking for one sweep of the blades,
you can get the cross-over moving at faster than the speed of light,
but you cannot send information faster than light.
	Not to be a spoilsport or anything, but how thick would the blades
of such scissors have to be in order to keep them from breaking under
the stress of the force to move them, or at least to prevent mechanical
bending that far outsizes the relativistic bending?
	I hear that if you accelerate a meter stick made of 3 cm on a side
spring steel up to 50% the speed of light, at the maximum rate that
won't permenently deform it more than 1 mm, it will as far away as Venus
when it gets up to speed.