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/