This thread needs to die. The speed of light has nothing to do with this mailing list, period.
Let this be the last post to it. Thank you! Cheers, Brian Szymanski [EMAIL PROTECTED] > In message: <[EMAIL PROTECTED]> > Gregory Bond <[EMAIL PROTECTED]> writes: > : Rob wrote: > : > : >>> You'd better cite your source and / or reasoning, as ~3*10^8m/s =is= > : >>> the > : >>> accepted constant speed of light in vacuum. > : >> > : It's deeper than that. The "second" and the "meter" are both defined in > : terms of wavelengths of light, which (as a consequence) fixes the speed > : of light _by definition_, at _exactly_ *299 792 458 m s^-1. > > The second is not defined in terms of the speed of light. It is > defined in terms of the number of hyperfine transitions of cesium: > > http://www.bipm.fr/en/si/si_brochure/chapter2/2-1/second.html > The second is the duration of 9 192 631 770 periods of the > radiation corresponding to the transition between the two > hyperfine levels of the ground state of the caesium 133 atom. > This definition refers to a caesium atom at rest at a > temperature of 0 K. > > The meter used to be defined in terms the wavelength of Krypton-86 > radiation, but that was changed in 1983. It is nowdefined in terms of > how far light travels in a given time interval. See > http://physics.nist.gov/cuu/Units/meter.html for a good historical > perspective. > > So the definition of the meter is dependent on the second, but the > second is independent. > > However, the definition implicitly assumes that today's fundamental > constants of the universe are indeed constant. There's been some > evidence that suggests, but is so far inconclusive, that some or all > of the fundamental constants of the universe may vary on the order of > a few parts in 10^15 over the last few billion years or so. The > definition of the meter was changed before this evidence was known. > > And this is indeed, very off topic. > > Warner > > _______________________________________________ > [EMAIL PROTECTED] mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to "[EMAIL PROTECTED]" > -- Brian Szymanski [EMAIL PROTECTED] I prefer pgp encrypted email: keyid: 4E7A4703 server: keys.indymedia.org fingerprint: 5BD3 0B0C C8E3 0746 3550 5648 0CFE 1BE7 4E7A 4703 _______________________________________________ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "[EMAIL PROTECTED]"
