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.
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