how do ppl know there is 24 hours in a day it could b longer or shorter?

Answer 1

How do we know you don't make sense. You common sense please its not that hard.

Answer 2

The 24 hour day is based around the time it takes for the sun to appear at the same place in the sky, and labelled as a rotation of the earth about it's axis. This is the synodic or Solar day. Astronomers realised that this is actually a falsehood. Because the Earth not only rotates about its axis but also orbits around the sun, to get the sun back to the same place as previously, the earth must rotate a little bit more (this can be comprehended a little more if you draw a path of the earth around the sun, and the earths rotation (both rotations are anti-clockwise). If you mark a position on the surface of the earth facing the sun, then draw the earth a little further on in the orbit you will notice that the earth has had to rotate a little further for the blob to face the sun.

Astronomers, (loving the night as they do) discovered that the stars are the best thing to measure a rotational period due to their relatively small movement. Thus the time for a star to return to it's previous position is 'a day'. This is the sidereal day, 3 minutes 55 seconds shorter than the day we all use.

So, every four years the numbers build up enough for there to be space to insert a whole extra day (the leap year!) Which is every four years and every year divisible by 400. There is also a leap second every so often,the exact timing of these i can't remember.

I guess the answer is that there are indeed less than 24 hours in a sidereal day, but 24 hours in the days we tend to go by!

Answer 3

Well considering time is a man made object then if everyone in the world decided that a day would only have 1 hour in it they could or maybe even 100 hours, or anything they wanted. That is how it all started and they decided on seconds, and 6o seconds in a minute and 60 seconds in an hour and 24 hours in a day and 7 days in a week, etc etc etc.

It does come down to rotation of the sun of course, basically it takes nearly 24 hours for the earth to go round the sun so it is kind of a neat thing to say that a day lasts that long.

PLus the first people to make sundials will have noticed how long the sun cast a shadow on it and they worked out how to divide it into a measurable distance and thus the 24 hours in a day were born.

Answer 4

It depends what you define as a day. The conventional 24-hour day is based upon the position of the Sun in the sky as viewed from the Earth.

The gravitational influence of the Moon is not the reason for the discrepancy of the 24-hour day.

The orthodox definition of the day is the time taken for the Earth to make one complete revolution about its axis. In the time it takes for the Earth to revolve about itself, it has also travelled some distance around the Sun as well, so after each true day the Sun is at slightly lower points in the sky. Therefore the 24 hours we count as a "day" are ever so slightly more than its correct value of about 23 hours 56 minutes.

Answer 5

There are just less then 24 hours a day now. In the distant past there were less then 24 and in the future there will be more. Assuming we don't change the length of the second to compansate. The moon is stealing our angular momentum as it drifts away making the day longer (slowly) all the time. So the number of hours in a day is changing fractionally every second. So it's not a bad question ^^^.

Answer 6

One day is the period of time for the earth to rotate about its diameter from west to east.

The ancient people divided this time into some convenient intervals (for them) of 24 hours.

Thus one day is divided into 24 hours and strictly speaking, 24 hours is not one day.

Latter it is found that, the day is only 23 hours 56 minutes and 4 seconds.

This day is the actual day and it is 23 hours 56 minutes and 4 seconds.

But we are using 1 day as 24 hours.

Thus during a year, the error is accumulated. This is compensated by introducing leap year.

Answer 7

oh my dear there r not 24 hours in a day
the day is slightly shorter than 24 hours
the scientists took the revolution of moon as the basis
they noticed the position of moon at a particular time and recorded the time when the moon again reaches the same position and this time period was found to be a bit less than 24 hours which is known as i day

Answer 8

Hour is a standard man made unit of measurement.
The day is the time the earth takes to make a one complete rotation around its axis.

If you divide the day by hours you'll get 24 hours.
(That is actually because the hour is originally quantified by dividing a day into 24 numbers and naming such period of time as an hour...)

So no need to worry. There are 24 hours per day.

If you are more curious, there are alternative measuring units. For example there was an ancient Sri Lankan unit called 'Sinhala peya'. As I remember there were 40 such units for the duration of a complete day.

Answer 9

The ancient Egyptians are credited with dividing the night into 12 parts. The 12 parts are measured by the appearance of different stars over the horizon. As you have 12 parts to the night, you have 12 parts to the day, hence 24 hours.

Why they've chosen those particular stars, I don't know. Maybe they were the brightest? Maybe they all line up to form a special shape?

Answer 10

'Ppl' know that there is 24 hours in a day because of the daily rotation of the Earth. This consists on how many times that it rotates and that it stays lit in one place from the sun and darkens from the moon.

Answer 11

A cat's being pregnant is going for sixty 4 days. The kittens are feelable at about a month alongside and also you may want to sense them bypass 2 weeks earlier the mum provides start. even as she starts scratching for an section to provide start, you already know you're purely hours faraway from being a serogate mom. she will have the ability to start up generating milk even as the kittens are born.