What OS are you? fun

[Rob]

M. Warner Losh wrote:

>In message: <41A1684E.1020302 at itga.com.au>
>            Gregory Bond <gnb at itga.com.au> 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
>
>
>  
>
Like I said before, go to www.nist.gov and read for yourself about all 
of this topic.  Lets close it on that note LOL.  Rob.