[time-nuts] Standards for units

[Chuck Harris]

David Dameron wrote:
> Hi all, 
> I just realized that a meter is defined by the speed of light., see
> http://physics.nist.gov/cuu/Units/meter.html
> It is only to 9 significant digits, so if the speed of light (in some
> controlled environment) is measured more precisely than this, the meter and
> all other derived length units will change?
> 
> (I was taught that 1 meter was 39.37 inches, to define the inch
> , but now I see more of 1 inch = 2.54 cm, as someone just referred to.)

1 meter/39.37 inches = 0.02540 meters/inch = 2.54 cm/inch = 25.4 mm/inch

Exactly.

-Chuck Harris