## Division of time

Humans have divided little amounts of time according to their convenience, making it easier for us to track and calculate. It is very important that these time divisions are universal so that people from all over the world agree to them and abide by them.

## Different kinds of divisions

100 years is a century, 10 years is a decade. There are 365 days in a year and 28-31 days in each month. Every week has 7 days each and a year has approximately 52 weeks. A fortnight is 14 days long. Each day is divided into 24 hours and each hour is divided into 60 minutes. Similarly, every minute is also divided into 60 seconds.

## An hour is a smaller unit of time

Compared to a year, an hour is a lot smaller.

## Calculation

We have to convert years into days and then into hours. As we know, there are 365 days in a year and each day has 24 hours each. By using that relation, we can easily find out the number of hours in a year. (See How many seconds are there in an hour?)

## The math

To calculate the number of hours in a year you need to multiply the number of days in a year by the number of hours each day. Now, we know that in a day there are 24 hours and that there are 365 days in a year.

24hours/day∗365day=8760hours

24hours/day∗365day=8760hours for a year

24hours/day∗366day=8784hours

24hours/day∗366day=8784hours for a leap year## A sidereal year

Is the time needed by the Earth to complete its orbit around the Sun and it lasts, on average, 365 days, 6 hours, 9 minutes, and 6 seconds.

To know the number of hours in a sidereal year we need to:

Convert 365 days in hours, multiplying by 24:

365∗24=8760hours

365∗24=8760hours

Convert 9 minutes into hours, dividing by 60 (the number of minutes in an hour):

9minutes=(9:60)hours=0,15hours

9minutes=(9:60)hours=0,15hours

Convert 6 seconds into hours, dividing by 60 (the number of seconds in an hour):

6seconds=(6:3600)hours=0,0017hours

6seconds=(6:3600)hours=0,0017hours

Add all the different answers plus 6 hours.