Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site utastro.UUCP Path: utzoo!watmath!clyde!burl!hou3c!hocda!houxm!vax135!cornell!uw-beaver!tektronix!hplabs!hao!seismo!ut-sally!utastro!ethan From: ethan@utastro.UUCP (Ethan Vishniac) Newsgroups: net.physics Subject: Re: Radius of Universe Message-ID: <545@utastro.UUCP> Date: Tue, 18-Sep-84 14:56:38 EDT Article-I.D.: utastro.545 Posted: Tue Sep 18 14:56:38 1984 Date-Received: Tue, 25-Sep-84 09:41:32 EDT References: <13494@sri-arpa.UUCP> Organization: UTexas Astronomy Dept., Austin, Texas Lines: 15 [This line is blank] This is a well known problem in the unification of gravity and the rest of physics. Simply put the problem is that the energy zero-point is arbitrary in most of physics. If you add a potential energy which is constant in space and time it doesn't affect anything. However, one's naive interpretation of gravity would be that since all mass-energy couples to gravity that this uniform background is self-gravitating and produces a gravitational field. The hope is that when gravity is unified with the other forces of nature there will be some obvious way of seeing that the zero-point oscillations of the various background fields don't couple to the gravitational field. There is no generally accepted approach to solving this problem. Ethan Vishniac