Solved Why is a day divided into 24 hours ?

[gladson1976]

Why is it that a day has 24 hours and not 20 or 25 ?
Why is an hour divided into 60 minutes and not 50 ?
Why does an year have 12 months ?

What is the basis for these divisions ?

 

[sdadamo]

A year has 12 months because that's the time it takes for the Earth to fully rotate around the sun; therefore one hour is 1/24 of a solar day as much as a minute is 1/60 of an hour. In Astronomy, a minute is a unit of angle and it is fully entitled as a "minute of right ascension". If you take Astronomy you'll learn more about it in-depth. We use these measurements to get accurate numbers used to define science and its information thus forth. There are leap seconds or sometimes one minute is 59 or 61 sec. It's not always as precise as that, hence why we use uncertainty in science.

 

[AddRAM]

And the moon takes roughly 28/29 days to orbit the earth etc.

I always thought 60 minutes was silly, but they had to name the show something LOL.

I love Astronomy.

 

[kronckew]

i blame the sumerians for the sexagesimal system.

some places use 'grads' for measuring angles, ie. a 90 degree angle is 100 grads. a full circle has 400 grads. swatch 'internet' time divides a day into 1000 'beats'.

most of us however stick with the sumerian system because it works.

 

[sdadamo]

i blame the sumerians for the sexagesimal system.

some places use 'grads' for measuring angles, ie. a 90 degree angle is 100 grads. a full circle has 400 grads. swatch 'internet' time divides a day into 1000 'beats'.

most of us however stick with the sumerian system because it works.

Oh boy, watch us Americans try to get into that mess and create something that doesn't work :drool:

 

[FaberTech]

I can only imagine because earth's measured time is based on the relativity of earth's movement to everything else moving in the galaxy in sequence. but I'm sure it is mostly historical. there are probably many ways we could measure time. but why fix it if it aint not workin

 

[Kaktussoft]

A year has 12 months because that's the time it takes for the Earth to fully rotate around the sun; therefore one hour is 1/24 of a solar day as much as a minute is 1/60 of an hour. In Astronomy, a minute is a unit of angle and it is fully entitled as a "minute of right ascension". If you take Astronomy you'll learn more about it in-depth. We use these measurements to get accurate numbers used to define science and its information thus forth. There are leap seconds or sometimes one minute is 59 or 61 sec. It's not always as precise as that, hence why we use uncertainty in science.

From wikipedia:
A minute of arc, arcminute, or minute arc (MOA), is a unit of angular measurement equal to one sixtieth (1⁄60) of one degree. In turn, a second of arc or arcsecond is one sixtieth (1⁄60) of one arcminute. Since one degree is defined as one three hundred and sixtieth (1⁄360) of a rotation
=======
But we have 24 hours in a day and 360 degrees... So 15 times as much!

 

[FaberTech]

sounds good to me

 

[Everlong]

A full day is actually 23 hours and 56 minutes. The extra 4 minutes is the amount of time it takes for the Sun to return to it's meridional position in the sky.

 

[M1GU31]

Very interesting stuff here guys. Feel like I learned something new today.

 

[smarteyeball]

Why does an year have 12 months ?

It's how it's been since the Romans tweaked the Greek Calendar.

The Romans borrowed parts of their earliest known calendar from the Greeks. The calendar consisted of 10 months in a year of 304 days. The Romans seem to have ignored the remaining 61 days, which fell in the middle of winter. The 10 months were named Martius, Aprilis, Maius, Junius, Quintilis, Sextilis, September, October, November, and December. The last six names were taken from the words for five, six, seven, eight, nine, and ten. Romulus, the legendary first ruler of Rome, is supposed to have introduced this calendar in the 700s B.C.E.


According to tradition, the Roman ruler Numa Pompilius added January and February to the calendar. This made the Roman year 355 days long. To make the calendar correspond approximately to the solar year, Numa also ordered the addition every other year of a month called Mercedinus. Mercedinus was inserted after February 23 or 24, and the last days of February were moved to the end of Mercedinus. In years when it was inserted, Mercedinus added 22 or 23 days to the year.

 

[madcratebuilder]

i blame the sumerians for the sexagesimal system.

some places use 'grads' for measuring angles, ie. a 90 degree angle is 100 grads. a full circle has 400 grads. swatch 'internet' time divides a day into 1000 'beats'.

most of us however stick with the sumerian system because it works.

We have a winner folks.

25hrs would need a 400* circle

I support the metric system every inch of the way.

 

[gladson1976]

Thanks for all the insights guys and gals.
The technical / astronomical answers were really good. What I really wanted to know was why the 12's were preferred over the 10's, which kronckew has provided the answer.

My question was really like, Why can't we have 400 degrees for a circle or 25 hrs a day. Why the Base 60 ?
https://en.wikipedia.org/wiki/Sexagesimal