360 degrees and 365 days: Correlation?

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Sorry if this is the wrong forum. Is there a correlation between 360 degrees in a circle and 365 days in a year? Did there use to be 360 days in a year in different calendars? because the ancients might have thought a year cycle was a perfect circle?
 
I vote for coincidence, not correlation.

There’s actually 365.25 days in a year, and we add a leap day when those bits add up to a whole day. That figure is probably not exact either, in fact I know it’s not. Every 7000 years we have to add another day, so February will have 30 days, one year in the distant future.

and, this does not account for the slowing of the rotation of the earth, but within our lifetime, that will not be a factor.
 
I vote for coincidence, not correlation.

There’s actually 365.25 days in a year, and we add a leap day when those bits add up to a whole day. That figure is probably not exact either, in fact I know it’s not. Every 7000 years we have to add another day, so February will have 30 days, one year in the distant future.

and, this does not account for the slowing of the rotation of the earth, but within our lifetime, that will not be a factor.

You might look into the different Jewish calendars. I vaguely recall their months have 30 days, which would give a year of 360 days, but then some years they have a whole other month, 13, to make up for the other shorter years. I’m surprised that ancient people paid that much attention and figured out a solution to establishing the definition of a year.

There are also leap seconds, but I forget what that refers to.

On the other hand, 360 degrees was an invention, more specifically a definition, that was useful more and more in astronomy and mathematics. You could define a compass with 720 degrees, as well; early mathematicians were limited by physical measurement devices.

In fact, this solves the problem I had in a very lame science project that I did 50 years ago in high school. My geometry book had a short story at the end of a chapter about a difficult problem. You cannot tri-sect an angle using a ruler and compass – if I remember the problem accurately. So, if you start off with a compass of 1440 degrees, or 2880 degrees, you can certainly estimate the three equal parts of an angle with more accuracy and precision. An exact answer is not often important in practical terms. One is often looking for an answer that is close enough.

I heard a skeptical statement on TV the other night, in a British detective program, I think it was. The man said, “truth is what people believe.” That is close to my estimating the three parts of an angle with my 2880 or 5760 degree compass. My estimate of the three equal parts of an angle is “true” to a certain degree of accuracy. (I probably should have said protractor instead of compass; it’s been a long time since geometry and trig, for me)
 
I’d imagine that the ancients counted the days between the return of seasonal cycles, and then rounded down, because 360 is so much more convenient than 365 or 370 in terms of factors. It fits nicely into base-10, base-12 and 60, and base-20 mathematics.

IMS, the Hebrew, Aztec and Mayan calendars were 360-based.

ICXC NIKA
 
FWIW, the leap is dropped in centennial years, unless it divides by 400. So 2100 is not a leap year. There will not be a 2/30 for a **very **long time.
 
About four to five thousand years ago, around the same time that Stonehenge in England was constructed, the Sumerians noticed that the Sun’s position in the sky moved and that it took about 360 days to get back to the same spot. This led to the development of a 360 degree circle.
 
Qwikness said:
Sorry if this is the wrong forum. Is there a correlation between 360 degrees in a circle and 365 days in a year? Did there use to be 360 days in a year in different calendars? because the ancients might have thought a year cycle was a perfect circle?
Click to expand...
60 and 360 was a sacred number in Mesopotamian cultures.
 
JurisPrudens said:
60 and 360 was a sacred number in Mesopotamian cultures.
Click to expand...
They were. And 1 hour of rotation is 15 degrees. There’s 24 hours in a day so 24*15 = 260 degrees in a (sidereal) day. The degrees of rotation in a solar day vary ever so slightly.

But yes, coincident.
 
ThinkingSapien said:
They were. And 1 hour of rotation is 15 degrees. There’s 24 hours in a day so
Code: 
24*15 = 260
degrees in a (sidereal) day. The degrees of rotation in a solar day vary ever so slightly.

But yes, coincident.
Click to expand...
I hope that was a typo?

Wikipaedia seems undecided on the question. But since it seems that 360 divisions to a circle occurred to several ancient cultures, it would not surprise me if there was not some correlation.

And: Yes, IIRC, some ancients devised calendars of 360 days – They knew it was not correct, however, and would also celebrate 5 or 6 extra days outside of calendar time.

tee
🤓
 
If I remember correctly, the Egyptian astronomer Ptolemy (lived first and second century AD) was the first to come up with the concept of dividing a circle into 360 equal parts. He stated very clearly the reason why he chose that number. It was because it is divisible into a lot of smaller numbers, such as 1, 2, 3, 4, 5, 6, 8, 10, and 12. It had nothing to do with the number of days in the year.
 
sirach2v4 said:
I vote for coincidence, not correlation.

There’s actually 365.25 days in a year, and we add a leap day when those bits add up to a whole day. That figure is probably not exact either, in fact I know it’s not. Every 7000 years we have to add another day, so February will have 30 days, one year in the distant future.

and, this does not account for the slowing of the rotation of the earth, but within our lifetime, that will not be a factor.

You might look into the different Jewish calendars. I vaguely recall their months have 30 days, which would give a year of 360 days, but then some years they have a whole other month, 13, to make up for the other shorter years. I’m surprised that ancient people paid that much attention and figured out a solution to establishing the definition of a year.

There are also leap seconds, but I forget what that refers to.

On the other hand, 360 degrees was an invention, more specifically a definition, that was useful more and more in astronomy and mathematics. You could define a compass with 720 degrees, as well; early mathematicians were limited by physical measurement devices.

In fact, this solves the problem I had in a very lame science project that I did 50 years ago in high school. My geometry book had a short story at the end of a chapter about a difficult problem. You cannot tri-sect an angle using a ruler and compass – if I remember the problem accurately. So, if you start off with a compass of 1440 degrees, or 2880 degrees, you can certainly estimate the three equal parts of an angle with more accuracy and precision. An exact answer is not often important in practical terms. One is often looking for an answer that is close enough.

I heard a skeptical statement on TV the other night, in a British detective program, I think it was. The man said, “truth is what people believe.” That is close to my estimating the three parts of an angle with my 2880 or 5760 degree compass. My estimate of the three equal parts of an angle is “true” to a certain degree of accuracy. (I probably should have said protractor instead of compass; it’s been a long time since geometry and trig, for me)
Click to expand...
Wow, your compass is just getting bigger and bigger 😉

And also. You have a fantastic memory. I’m actually really impressed. 👍
 
ToddBlankenship said:
If I remember correctly, the Egyptian astronomer Ptolemy (lived first and second century AD) was the first to come up with the concept of dividing a circle into 360 equal parts. He stated very clearly the reason why he chose that number. It was because it is divisible into a lot of smaller numbers, such as 1, 2, 3, 4, 5, 6, 8, 10, and 12. It had nothing to do with the number of days in the year.
Click to expand...
Interesting, given that the Babylonians and Phienicians used base-60 numeration, and are supposedly the source behind the degree-based navigation we use now.

ICXC NIKA
 
You might look into the different Jewish calendars. I vaguely recall their months have 30 days, which would give a year of 360 days, but then some years they have a whole other month, 13, to make up for the other shorter years. I’m surprised that ancient people paid that much attention and figured out a solution to establishing the definition of a year.
Click to expand...
The determination of the year was arguably more important in antiquity than now, due to the requirements of subsistence-level farming (some crops have only a days-long window to plant) and of flimsy sea transportation in unpredictable weather.

ICXC NIKA
 
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