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From: jeff@rtech.ARPA (Jeff Lichtman)
Newsgroups: net.misc,net.physics
Subject: Re: perpetual motion
Message-ID: <262@rtech.ARPA>
Date: Mon, 25-Mar-85 05:22:36 EST
Article-I.D.: rtech.262
Posted: Mon Mar 25 05:22:36 1985
Date-Received: Thu, 28-Mar-85 06:45:42 EST
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Organization: Relational Technology, Berkeley CA
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Xref: watmath net.misc:7675 net.physics:2328

> 
> 	Could someone kindly translate the above into English
> 	for those of us who don't often see phrases like
> 	"time translation invariance"
> 		 and
> 	"vanishing divergence of stress-energy-momentum tensor"?
> 
> 	Thanks.

"Time translation invariance" means that the laws of physics don't change with
time.  The results of an experiment are the same, regardless of when you do it.
This law and the law of conservation of energy are equivalent. I don't know how
to prove this, but I read it in a book on the fundamentals of physics.

I don't know what "vanishing divergence of stress-energy-momentum tensor"
means.
-- 
Jeff Lichtman at rtech (Relational Technology, Inc.)
aka Swazoo Koolak