From: utzoo!decvax!harpo!eagle!jerry
Newsgroups: net.misc
Title: Re: what is time
Article-I.D.: eagle.429
Posted: Fri Jul 30 00:09:59 1982
Received: Sat Jul 31 00:30:26 1982
References: hplabs.582 pur-phy.414


If you are interested in the question "what is time" and have
a fairly good physics background I would recomend 

		The Physics of Time Asymettry
		by P. C. W. Davies
		University of California Press
		(1977 edition)

It's first sentence describes its topic. "How is it
possible to account for the difference between past and future
when and examination of the laws of physics reveals only the
symmetry of time?"

His answer (as best I understand it -- my physics isn't up to
really understanding the book) is cosmological.  I quote (p. 109)

"We have reached a remarkable conclusion.  The origin of all thermodynamic
irreversibility in the real universe depends ultimately on gravitation.
Any gravitating universe that can exist and contains more than one type
of interacting material must be asymettric in time, both globally in
its motion, and locally in its thermodynamics."

Jerry Schwarz -- BTL Murray Hill -- eagle!jerry