Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!watmath!clyde!cbosgd!ihnp4!qantel!hplabs!sri-unix!Cramer%CSL60%ti-csl.csnet@CSNET-RELAY.ARPA From: Cramer%CSL60%ti-csl.csnet@CSNET-RELAY.ARPA Newsgroups: net.physics Subject: Re: Do Positrons Have Negative Mass? Message-ID: <551@sri-arpa.ARPA> Date: Tue, 17-Sep-85 11:16:00 EDT Article-I.D.: sri-arpa.551 Posted: Tue Sep 17 11:16:00 1985 Date-Received: Sat, 21-Sep-85 04:31:41 EDT Lines: 14 From: Nichael >>How can we tell that Andromeda, say, is composed of matter and not >>anti-matter? What observational differences would there be between a matter >>galaxy and an anti-matter galaxy? The space between the Milky Way and Andromeda isn't a perfect vacumn. Were Andromeda made of anti-matter, there would have to be matter/anti-matter frontier somewhere between us. I don't have any numbers to back this up, but it seems that the resulting spike in the background radiation at ~1MeV would be easily observable. NLC ------- Brought to you by Super Global Mega Corp .com