Why 60 Minutes? The Sumerian Legacy

We use base-10 (decimal) for almost everything: money, weight, distance, and even counting on our fingers. But when it comes to time, we suddenly switch to 60. Why do we have 60 seconds in a minute and 60 minutes in an hour? The answer takes us back 5,000 years to ancient Mesopotamia.

The Sumerians and Base-60

The Sumerians (and later the Babylonians) used a sexagesimal (base-60) number system. While it seems strange to us today, 60 is a highly practical number for ancient mathematicians. Unlike 10, which can only be evenly divided by 2 and 5, the number 60 can be divided by 2, 3, 4, 5, 6, 10, 12, 15, 20, and 30.

This made fractions incredibly easy to calculate without needing complex decimals—a vital feature for ancient commerce and astronomy.

The Geometry of the Sky

The Babylonians were master astronomers. They divided the circle of the sky into 360 degrees (6 x 60). Because their year was approximately 360 days long, one degree matched roughly one day of the sun's travel along the ecliptic.

From Babylon to the Modern Watch

The 60-unit division was preserved by Greek astronomers like Hipparchus and Ptolemy, who used it to divide the Earth’s latitude and longitude. Later, 14th-century mechanical clockmakers adopted these mathematical divisions for the face of the clock.

The word "minute" comes from the Latin pars minuta prima (first small part), and "second" comes from pars minuta secunda (second small part).

Why Not Change to Decimal Time?

During the French Revolution, the government tried to introduce Decimal Time: 10 hours in a day, 100 minutes in an hour, and 100 seconds in a minute. It was a failure. People were so used to the sexagesimal system—and so many clocks were already built for it—that the law was repealed after only 17 months.

Conclusion

Every time you look at the Epoch Clock or your own watch, you are participating in a mathematical tradition that is older than the Pyramids. We may live in a digital, decimal age, but the heartbeat of our civilization remains resolutely Sumerian.