Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/3/84; site talcott.UUCP Path: utzoo!watmath!clyde!cbosgd!ihnp4!zehntel!hplabs!hao!seismo!harvard!wjh12!talcott!gjk From: gjk@talcott.UUCP (Greg J Kuperberg) Newsgroups: net.physics Subject: Re: quo vadis gravity? Message-ID: <181@talcott.UUCP> Date: Tue, 11-Dec-84 12:12:54 EST Article-I.D.: talcott.181 Posted: Tue Dec 11 12:12:54 1984 Date-Received: Fri, 14-Dec-84 04:42:02 EST References: <184@decwrl.UUCP> Organization: Harvard Lines: 20 > > >The gravitational field does not "travel" at all. > > If e=mc**2 and matter and mass are converted in an atomic bomb... shouldn't > something happen to the gravitational field of the "former" mass? A common myth: mass is not conserved, energy is not conserved, but the sum of the two is. This myth is in part propagated by Isaac Asimov and other popular science writers. Now here's reality: Mass *is* energy, and it is conserved. In fact, one more conservation law was thrown in: momentum. Whereas B.E. (before Einstein), we had the conservation of mass, the conservation of energy, and the conservation of momentum, A.E. (after Einstein), we have the conservation of energy-momentum (energy being equal to mass). Energy can be thought of as "momentum in the time direction". --- Greg Kuperberg harvard!talcott!gjk "Strange women lying in ponds distributing swords is no basis for a system of government." -Monty Python