Origin of the 360-Degree Circle
Date: 11/10/1999 at 07:31:54 From: Tommy Griffin Subject: Babylonians Did the Babylonians discover the 360-degree circle?
Date: 11/10/1999 at 08:01:39 From: Doctor Jerry Subject: Re: Babylonians Hi Tommy, According to Otto Neugebauer (in his _The Exact Sciences in Antiquity_), who is one of the world's leading experts in ancient mathematics and astronomy, "A second Egyptian contribution to astronomy is the division of the day into 24 hours, though these hours were originally not of even length but were dependent upon the seasons." A little further on he says, "Thus our present division of the day into 24 hours of 60 minutes each is the result of a Hellenistic (Greek) modification of an Egyptian practice combined with Babylonian numerical procedures." As you may know, the Babylonians/Mesopotamians used base 60 numbers in their business, astronomy, and mathematics (they used base 10 numbers as well). Probably connected to this was the division of the circumference of a circle into 360 parts by Babylonian astronomers. Geometric circles and the apparent movement of stars on the celestial sphere go naturally together and time is a common feature of astronomy. I think, then, that it was natural to use the division of a circle on a clock face. However, Otto Neugebauer (again in his _The Exact Sciences in Antiquity_) also says that, "The division of the circumference of the circle into 360 parts originated in Babylonian astronomy of the last centuries BC. The [base 60] number system as such is many centuries older and has nothing to do with astronomical concepts." - Doctor Jerry, The Math Forum http://mathforum.org/dr.math/
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