In message <4e7c7556.6090...@hvsistemas.es>, Javier Herrero writes: >nr 2 = nr 3 is an assumption? I was thinking that it is a definition :)
No, not really. Maxwells equations talk about electromagnetic waves in empty space under the assumption that they have zero rest-mass, but we have never proved those waves to be photons, for instance by proving photons to have zero rest-mass. We have never been able to actually measure a rest-mass for the photon either, at best we have experimentally constrained it to be less than x * 10^-16 eV. Based on that everybody _assume_ that it is mathematically zero, and photons therefore identical to Maxwells EM-waves. But we do not actually have a proof of that, it is only an assumption. The neutrino was in a quite similar position until a few years go: My entire generation grew up with neutrinoes being mass-less "just like photons" and then we suddenly found out it probably wasn't mass-less. Mind you: My money is on experimental mistake, quite likely application of insufficient general relativity. But if the experiment holds up to scrutiny and is replicated, my money will not be on overrelativistic neutrinos, but on photons having rest-mass, because that would leave the theory of relativity standing and confine the damage to only the already somewhat troubled standard-model. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.