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Why are hours and minutes based on the number 60?

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We count 60 seconds in a minute, and 60 minutes in an hour. This system is fully anchored in our society, and this has been the case since antiquity, with a few minor exceptions. But why a base of 60 for measuring time? 

To find the origins of the base of the number 60 for measuring minutes and hours, we have to go back to ancient times. It was around 3000 years before Christ (BC) that the Babylonians decided to divide the year up into the way we known it today -12 months of around 30 days each.

This system was ideal at the time, as they based it on lunar cycles, on the period of the revolution of the Earth around the sun, as well as on their method of counting on their fingers: using the thumb to count out each of the 12 finger joints. This is how they divided a circle into 36: 12 x 30 = 360.

While we now make things easier by counting in tens, the Babylonians appear to have had a preference for and an ability to count in sixties. If this was the case, it is very likely to be because the number 60 is divisible by multiple divisors: 2, 3, 4, 5, 6, 10, 12, 15, 20 and 30, which is not the case with the number 10.

A 24 hour day is also thanks to our ancestors, who, as they divided the year in 12, also divided the day into 12 hours and the night into 12 hours, with a total of 24 hours.

Surprising fact: in the course of European history, more particularly in France, it wasn’t always the case! After the French Revolution, the ministers of the First Republic wanted to put in place a new vision of the passage of time. The weeks thus were counted as 10 days long instead of 7, and were called ‘décades’. Article 11 from a decree in November 1793 thus stated: The day, from midnight to midnight, is divided into ten parts or hours, each part into ten others, and so on until the smallest commensurable portion of time. A hundredth of an hour is called a decimal minute; a hundredth of a minute is called a decimal second.”