Why the number 12 is used to tell time

The number 12 shows up prominenty in our calendar, how we we tell time, several major religions, and even in music.
This first video is on the science behind it, The second one regarding its usage in religions And the third it's usage in music, which gets a little more mathy And what I'd like to argue is that this number showing up is not a coincidence There is a reason behind it, Before we get to the importance of the number 12, let’s start with a bigger number, 360 A number you’re probably familiar with, with regards to the unit circle, represented by 360 degrees around the circle.

But why 360 degrees in a circle, well, The ancient Babylonians’ used this and they also considered there to be 360 days in a year, just like the ancient Hebrews did. It’s very interesting they chose this isnt’ it? Because we know that a year is based on earths full orbit, or circle if you will, around the sun. 360 days (off by 5 technically) then the seasons repeat, but it doesn’t seem that our heliocentric understanding of the solar system came until much, much later than the Babylonians, so it’s very interesting they chose this number of days in a year to represent the number of degrees around the unit circle. The Babylonians also used a sort of base 60 number system and 360 was 6x60’s, so it’s a very mathematically convenient number.

So 360 can be divided evenly by 60, or 6, or by many other numbers. It is in fact regarded as a ‘highly composite number’ in that it has more divisors than any smaller number 1,2,3,4,5,6,8,9,10,12,15,18,20,24,30,36,40,45,60,72,90,120,180 and 360 All divisors of 360, lots of them One of those very important divisors of 360 is 12, which is also a ‘superior highly composite number’, in that it has more divisors than any number smaller than it. 12 is of course important in the context of the year, because there are 12 months in a year.

And where does the definition of month come from, well, think of the origin as ‘moonth’. This is not just true in English but the word for month in Mandarin and many other, if not most, languages comes from their terms for the moon as well. English Moon Moonth Mandarin 月 (yue) 月 (yue) Indonesian Bulan Bulan Turkish Ay ay So we have 12 months in a year in our calendar, and the ancient Babylonian and Hebrew calendars did too, except their months were all 30 days long.

Why 30, well, the moon orbits the earth in a little over 27 days. However, in that time it takes to orbit, the earth has gone about 30 degrees around the sun, so the moon needs to orbit a little bit more than one full rotation to go back to a new moon from the earth’s perspective. The new moon, by the way, happens when viewed from the earth, the moon is not reflecting any light from the sun, so it's basically when the moon falls between the earth and sun So you may notice that if in 30 days, the earth goes about 30 degrees around the sun, then each day the earth moves about 1 degree around the sun, with 12 months of 30 days giving 360 days in a year, each day like the earth moving (about) a degree. So the Babylonians choice of 360 degrees in a circle, after which the circle repeats, was quite ingenious.

And our use of the number 12 in keeping time doesn’t stop there of course, We use a circular clock to keep track of 12 hours as the hour hand completes one revolution in a half-day. So, we really like this number 12 when it comes to time and circles, and it shows. But these 12 ‘moonths’, if you will, also give rise to elements of human activity beyond just keeping track of time. Consider the Zodiac signs of astrology, which can be traced back all the way to the same Babylonians discussed earlier, and still constitute a sort of religion of astrology today. Perhaps you're familiar with the 12 Zodiac signs in Astrology, which are: Aries Taurus Gemini Cancer Leo Virgo Libra Scorpio Sagittarius Capricorn Aquarius, and Pisces And each represent a span of 30 degrees, or about a month, of the earth’s orbit around the sun.

So the prominence of the 12 signs in this religion clearly trace to the 12 lunar cycles in a year, So you can see that the 12 number is integral to the relation of the sun, moon and earth, which forms the basis for it’s importance in other areas of human existence as well, areas like religion, which is what we’ll look into in the next video. So check that out if you're interested. If some other instances of 12 in science come to mind though, let us know in the comments below.

But otherwise, have a good one, and take care.