🚀 go-pugleaf

In article <1992Aug10.174709.18689@nevada.edu>, rbond@nevada.edu (RICHARD BOND) writes...
>In article <1992Aug7.165808.1391@visus.com> jml@visus.com (Jim Large) writes:
>>  "The intersection of a pair of scissors"
>>		-- Cool idea, though I doubt that we'll ever make the 
>>		   the scissors which are perfect enough to actually 
>>		   do this experiment.
>  
>   Dumb idea; if you would review your relativity theory, you will see
>   that it points out that there is no such thing as a perfectly rigid
>   structure. No matter how long you made your scissors, the far end 
>   would not get the signal that the near end was moving any faster than
>   the speed of light. Or do I just not get the joke?

It's not a joke, but you didn't get it.  You are correct about the 
limiting speed of the tips of the scissors.  But Jim was referring to the
point of contact between the two blades, which speeds off towards the tips
at much faster than the speed of light if the two blades are long enough.
Imagine a pair of scissors with each blade two light-seconds long. They
are open at the far end by only 1 inch.  Now close the scissors.  The 
tips move 1 inch in, say, one second.  But the leading point of contact
travels down 2 light-seconds of blade in the same one second.

-Scott
--------------------
Scott I. Chase			"The question seems to be of such a character
SICHASE@CSA2.LBL.GOV		that if I should come to life after my death
				and some mathematician were to tell me that it
				had been definitely settled, I think I would
				immediately drop dead again."      - Vandiver