[Boatanchors] SI units and the rest

[mikea]

On Tue, Nov 16, 2010 at 07:21:30PM -0500, WA5CAB at cs.com wrote:
> I'm curious as to why it isn't 1/(3*10^8).  
> 
> In a message dated 11/16/2010 11:39:45 AM Central Standard Time, 
> w7qho at aol.com writes: 
> > The original definition of a METER  was based on a measured standard  
> > bar.  The standard was redefined in 1983 as the distance traveled by  
> > light in a vacuum during a time interval of 1/299,792,458 of a  
> > second,   The standard kilogram is a a cylindrically shaped platinum- 
> > iridium slug and is the only SI unit still defined by an artifact  
> > rather than a fundamental physical property that can be reproduced in  
> > different laboratories.
> > 
> > Dennis D. W7QHO
> > Glendale, CA

The second was deemed to be a more fundamental unit, since it could be
defined directly from a quantum transition, and so the meter became a
derivative unit defined in terms of the second. 

-- 
Mike Andrews, W5EGO
mikea at mikea.ath.cx
Tired old sysadmin