The question
Why does an hour have 60 minutes, and a circle 360 degrees?
The short answer
We inherited base-60 counting from ancient Mesopotamia. Sixty divides so many ways that astronomers kept it for time and angles, long after decimal counting won elsewhere.
What science knows
Historical FactSumerian and later Babylonian scribes counted in base 60 (sexagesimal) from the third millennium BCE. Greek astronomers such as Hipparchus and Ptolemy adopted it for angles and fractions, and it passed into medieval astronomy and clocks.
The words record the history: a “minute” is from the Latin pars minuta prima, the first small part, and a “second” is pars minuta secunda, the second.
The pattern
Established Mathematics60 is divisible by 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30 and 60. It is the smallest number divisible by every number from 1 to 6, which makes fractions like thirds exact rather than repeating decimals.
What is still uncertain
Mixed EvidenceWhy the Sumerians chose 60 is debated: its divisibility, a merger of counting systems, or finger-counting methods. The 360-degree circle may echo the approximate number of days in a year, but that link is uncertain.
Why humans find it interesting
Cultural TraditionThe Chinese calendar also counts a 60-year cycle, pairing 10 Heavenly Stems with 12 Earthly Branches.
CUE perspective
CUE PerspectiveEvery glance at a clock is a small piece of Babylonian mathematics. Numbers that were chosen because they work can outlast empires.
CUE’s Chinese astrology draws on the same 60-year cycle of stems and branches, a tradition CUE reads symbolically rather than scientifically.