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From: tino@hou2f.UUCP (A.TINO)
Newsgroups: net.physics
Subject: Faster-than-light Scissors
Message-ID: <482@hou2f.UUCP>
Date: Wed, 5-Jun-85 16:54:18 EDT
Article-I.D.: hou2f.482
Posted: Wed Jun  5 16:54:18 1985
Date-Received: Mon, 10-Jun-85 02:35:37 EDT
Organization: AT&T Bell Labs, Holmdel NJ
Lines: 23

>	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.

Let person A squeeze the handle and person B, at the far end,
rest his neck on the bottom blade.  If the scissors were rigid
I guarantee that some serious information could be transmitted
at faster-than-light speed even with a single pass of the blade.  
You don't need any wave-like motion to send information.

The intersection point of the blades never travels at
faster-than-light speed because, in the relativistic realm, the blades
aren't rigid. (As pointed out by Hummel. Hi Ed!)

			Al Tino, Bell Labs at Holmdel