From: utzoo!watmath!bstempleton Newsgroups: net.physics Title: Rest mass Article-I.D.: watmath.3239 Posted: Tue Aug 10 00:29:18 1982 Received: Tue Aug 10 04:55:40 1982 Where or where does the term 'rest mass' come from that we use? Everybody knows a photon has no 'rest mass', but who has ever seen a photon at rest?