A few weeks ago we discussed the origin of that word: leap year. However, since this year 2008 is a leap year, we might ask ourselves, why does a leap year exist? Well, here is a brief explanation:
This additional day became necessary because the duration of the astronomical year -that is to say, one complete turn of the earth in its orbit- is not exactly 365 days like the calendar year, but 365 days, 5 hours and 56 minutes.
A year is the period of time it takes the earth to go around the sun and approximately consists of 365 days, 5 hours, 48 minutes and 46 seconds, that is, 365 days and a quarter minus 11 minutes and 14 seconds.
It is usually rounded by saying that it lasts 365 and a quarter days. That quarter of a day accumulates, so that every four years one more day is added to the year, February 29, calling it a leap year.
Julius Caesar established the 365-day calendar with leap years and Gregory XIII reformed it as it is today.