[time-nuts] Why 9,192,631,770 ??

[Jim Lux]

On 5/9/12 4:27 PM, Charles P. Steinmetz wrote:
> Don wrote:
>
>> It's interesting to note (to ask?): When did someone get smart enough to
>> start measuring 1/86 thousandth of a day
>
> That is generally considered to be the 10th/11th century Persian Muslim
> mathematician and astronomer, Abu al-Rayhan Muhammad ibn Ahmad al-Biruni
> (a.k.a. Alberonius and Al-Biruni). His eclipse data was accurate enough
> that it was used in the late 18th century to help quantify the
> acceleration of the moon, and is still used by astronomers today.
>

as for why a second?

That's because of the popularity of base 60.  Dividing the day into 24 
hours (twice 12) relates a day to a year to zodiac constellations.  it's 
also got a lot of factors (2,3,4,6,etc)

Then dividing hours into 60 minutes, and minutes into 60 seconds makes 
sort of sense.

1 second is also close to the human heartbeat period (as opposed to, say 
using 1/100 hour or something like that)

The French Revolution did try to decimalize things, of course.