From: utzoo!decvax!duke!harpo!floyd!rhm Newsgroups: net.space Title: Re: Supernova, Gravity, Etc Article-I.D.: floyd.426 Posted: Fri Aug 6 16:09:11 1982 Received: Mon Aug 9 06:43:17 1982 Re ihnss!knudsen comment. Again, during a supernova explosion, the change in mass is zero, both instantaneously and long term. Photons do just as good a job of causing gravitation as anything else of the same mass.