Why is the world divided into 360 degrees?

I was with my husband and some friends last Thursday night and the conversation came around to sailing (as it so often does with these particular friends as they have a catamaran in Greece).

While we were talking someone mentioned the phrase ‘nautical miles’, so being the curious person I am I just had to know what the difference was between a nautical and a normal mile. Well it turns out that a nautical mile is 1.85200km and 1.1508 to a normal mile (so roughly half a mile extra).

Well, then we got on to how they are calculated and I was informed by my oh so clever spouse and one of my very favourite friends that the circumference of the world is divided into 360 degrees and each degree is divided by 60 minutes and 1 minute = 1 nautical mile.

Ah ha said I ‘so why is the earth divided into 360 degrees, wouldn’t it be easier to have it divided into 400 – because 360 is just an arbitrary figure isn’t it?’ So the conversation moved on apace with a furious discussion taking place about the fact that it has to be divisible by 12 etc…. blah blah blah – ‘but why is it divisible by 12?’ I asked.

And do you know what – there was no adequate answer so I decided to investigate because it seemed odd to me that someone had to have invented the reason why the earth was divided into 360 degrees. And I was right, it is arbitrary and was decided upon by the ancient Greeks who divided the year into twelve parts that they called months, each month was then divided in 30 parts called days. This meant that their year had 360 days and as the earth goes round the sun in around about 1 year in an almost circular transit, they decided to divide the world into 360 degrees.

Now the next question almost certainly has to be why twelve months and 30 days? – was this something to do with the sun coming back to the same place in the heavens each year – or is this another example of arbitrary inventions of men trying to pin something down and call it a ‘fact’.

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