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Author Topic: Why are there 24 hours in a day?  (Read 2859 times)

Offline dentstudent

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Why are there 24 hours in a day?
« on: 01/06/2007 14:20:23 »
I've never understood why the day is partitioned into 24 hours. 365 (.25) days a year is obvious, the origins of 12 months a year are pretty clear, but not the 24 hours per day. Can anyone shed any light on this? [?]


 

another_someone

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Why are there 24 hours in a day?
« Reply #1 on: 01/06/2007 14:40:51 »
The origins of the 12 months and 24 hours is not actually that different.

The Babylonians split the say up into 12 hours, based upon 12 constellations that passed across the sky, 12 hours for the day, and 12 for the night.  Those 12 constellations are the constellations upon which the signs of the Zodiac are based.

An extension of that, the Babylonians generally had a base 12 numbering system (i.e. they counted in dozens), which were then subdivided into five subunits, thus creating a base 60 overall numberring system, from which we get 60 minutes in the hour, and 60 seconds in the minute.
 

Offline dentstudent

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Why are there 24 hours in a day?
« Reply #2 on: 01/06/2007 14:52:37 »
Thanks for the answer! So were the constellations used as a sort of heavenly clock, so that each constellation passed at certain times? How did they register this during daylight, when it would be impossible to see the stars? And I guess this fluctuated during the year with the rotation of the earth?
 

another_someone

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Why are there 24 hours in a day?
« Reply #3 on: 01/06/2007 14:58:00 »
Thanks for the answer! So were the constellations used as a sort of heavenly clock, so that each constellation passed at certain times? How did they register this during daylight, when it would be impossible to see the stars? And I guess this fluctuated during the year with the rotation of the earth?

They used the stars at night (hence the constellations) and followed the Sun across the sky during the day.

Babylon is closer to the equator than we are, so changes in season would be less than is perceptible in Europe (especially northern Europe).  Nonetheless, it must be regarded as merely approximate, since some variance would still be there.
 

Offline DoctorBeaver

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Why are there 24 hours in a day?
« Reply #4 on: 01/06/2007 14:58:17 »
Just a wee tad of further information from the all-knowing beaver.

The Babylonians used the segments of their fingers to count, tagging them with their thumb. 4 fingers, 3 segments per finger, & voila... base 12! 4 fingers + 1 thumb = 5, hence the 5 sub-units.

It worked very well as the hours of the day could be indicated on 1 hand (the right) and the hours of the night on the other.

(No, they didn't drop their trousers for a leapyear!)
 

Offline dentstudent

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Why are there 24 hours in a day?
« Reply #5 on: 01/06/2007 15:00:00 »
Yes, well I was forgetting the sun of course! What a numpty.
 

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Why are there 24 hours in a day?
« Reply #5 on: 01/06/2007 15:00:00 »

 

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