Why is it one day has 24 hours only? can anyone explain it?

Just wait the next day will have 24 also..... You'll See..

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07 660 W/extras and adding more....

ha ha you are funny

My days have 24 hours... but each hour I spend at work seems about 7 hours long, and the hours I spend doing fun things only last about 20 minutes each.... I think it's called relativity

humm I'm just the opposite, things I like to do take me all day and the work I do takes me about 10 min.

But serious I would think you of all people would no the true answer to this question

If it was any onger I'd drop dead. I always try to get at least 48 hours worth of work done in 24.

Hope this helps...

Source: WikiAnswers

Nobody knows for sure why we have 24 hours - of whatever length - in a day.

But here are some theories:


The Eqyptians were fond of counting in base twelve (instead of base 10 which is commonly used today). This is thought to be because they counted finger joints instead of fingers. Each of your fingers has three joints, so if you count by pointing to finger joints with your thumb you can count to twelve on each hand. This might seem arbitrary, but is actually just a strange as counting in base ten simply because we have ten digits.

The Egyptians divided the clock into 12 hours of daytime and 12 hours of night-time (or alternatively 10 hours between sunrise and sunset, an hour for each twilight period and 12 hours of darkness). This is known because of various sundials from the period which have been found to be marked with hours. Interestingly this means that hours started out changing in length with the seasons (as the amount of daylight vs. darkness changes).

There is a more in-depth explanation for the division of night-time into 12 hours which is based on the number of "decan" stars which were seen to rise during summer nights in Ancient Egypt. A "decan" star was a star which rose just before sunrise at the beginning of a 10-day "decade" in Ancient Egypt. 36 "decan" stars marked the passage of a year for the Egyptians (or 36 10 day periods). During summer nights, 12 decan stars rose - one for each "hour".

However, hours did not have a fixed length until the Greeks decided they needed such a system for theoretical calculations. Hipparchus proposed dividing the day equally into 24 hours which came to be known as equinoctial hours (because they are based on 12 hours of daylight and 12 hours of darkness on the days of the Equinoxes). Ordinary people continued to use the seasonally varying hours for a long time. Only with the advent of mechanical clocks in Europe in the 14th Century, did the system we use today become common place.

Mathematics

My favourite theory is that 24 was simply a useful number. The day was divided into 24 hours for much the same reason as the old British pound was divided into 240 pennies: it made division easier.

24 can be divided easily by 2,3,4,6,8 and 12. So dividing a full day into three shifts is easy - eight hours each. On board ship there are six watches - so each is four hours long. If you want to buy someone's time for a quarter of a day (excluding the night), that's three hours of pay. Try doing that with a day made up of ten hours.

Finger Counting

A popular theory is that the Sumerians counted in base twelve rather than in the base ten we use today. This is said to have been done using the fingers.

If you look at the fingers - not the thumb - of one hand you will see that (for most people) each contains three segments. Three segments on each of four fingers gives twelve. The thumb can then be used to point to a particular segment and indicate a number.

So, twelve segments on each hand, one hand for day and the other for night - and we have a possible origin of the 24 hour day.

The Zodiac

The more mystically inclined like to think that the 24 hours figure comes from astrology and other such fields. The zodiac contains twelve signs and the number twelve has been considered important by many civilisations. So it would be natural to assign twelve hours to the night and twelve to the day.

Which Theory is Right?

We don't know which - if any - of the above theories is right. There's no reason that they can't all be.

It's entirely possible that the decision of the Sumerians to use a base 12 counting system was at least in part due to the utility of the number. Had nine been more useful than twelve, for example, then they could have ignored the little finger.

As for the zodiac, that could have simply been divided into twelve signs because the number twelve was already important.

So it's possible that all these factors merged together to give us the 24 hour day.

Resource:
http://curious.astro.cornell.edu/que...php?number=594
http://www.horology-stuff.com/time/24hours.html

Nice find man! Very informative.

I didn't even really know that we weren't sure of the origins. Learn somethin new everyday I guess.

or maybe just a simple math prob

A day is defined as how long it takes for a planet to rotate around its axis. A circle has 360°. Therefore, in one day the earth rotates 360°.

1 Day = 24 hours
1 Day = 360° of rotation
24 hours = 360° of rotation
1 hour = 15° of rotation

Yeah, this is right. It's based on the Earth's rotation.

All's fun and game until an asteroid hits earth and screws everything up. It'll happen...