Re: Metric Time (was Re: Why not 13 months? (Was La Systeme Metrique))

Whittet (
7 Oct 1995 14:24:26 GMT

In article <44rbs1$>, stgprao@seismic.sugarland.unocal.COM says...
>1) Time measurement is based on the correlation of semi-periodic phenomena-
>biological, astronomical, atomic, etc.
>2) Each one of thes phenomena has imperfections.
>3) There is a trade-off in time scales convenient for humans verus
>scientific precision.
>4) If you are going to stick with astronomy, one might as well use some
>galactic cycle to avoid earth chauvanism.
>5) An absolute measure of duration can be derived from fundamental physical
>constants such as Planck's unit of action and the speed of light. This very
>small unit is called Planck time.
>6) One could define a Planck second or Planck day in some multiple of Planck t
>either a decimal power for us ten-fingered humans, or a power of two for the
>computational world. That way the Planck second would be convenient for human
>s and
>absolutely precise for science.

How can you improve on the Egyptians discovery that the circumference of the
Earth at the equator in feet if divided into 360 degrees, or the number of
days in the Egyptian year, gives a distance equal in feet to the number of
days in a millenium, 1000 revolutions of the earth around the sun?

24902.72727 x 5280/360 =365240; 365240/1000 = 365.24

In round nunbers

Egyptian Royal cubit of 7 palms ~= 525 mm ~= 21 inches
1 1/2 common cubits ~= 6 palms or 450 mm ~= 18 inches
common cubit = 5 palms or 375 mm ~= 15 inches
Egyptian foot = 4 palms or 300 mm ~= 12 inches

Interestingly enough, the Roman foot of 296 mm and the English foot of 308 mm
have preserved this value over five millenia and are now to be discarded in
favor of the metric system.