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

[Charles P. Steinmetz]

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.

Best regards,

Charles