Why is an extra day added to Feburary every four years?

Question

I need to know guys please.Thank You.

Answer 1

Because the earth actually orbits the sun approximately every 365 1/4 days, not precisely every 365 days. By adding an extra day to the year one out of every four years, the seasons don't gradually shift to a different time of year.

Answer 2

The first answer above is correct. The second one is wrong. A mean SOLAR day is in fact exactly 24 hours long. It is the SIDEREAL day that is only 23h 56m 4s long. A solar day is the time from one sunrise to the next. A sidereal day is the time from one star rise to the next. Since the Earth orbits the Sun, the Sun seems to move against the background of stars as seen from Earth, so it takes a little more rotation of the Earth to bring the Sun back to the horizon.

The rotation of the Earth on its axis is not physically connected to the Earth's orbital revolution around the Sun, so it would be an amazing coincidence if the one were an exact multiple of the other. As it turns out, it isn't, and it is off by about 1/4 of a day, so we add a day every 4 years. But it isn't off by EXACTLY 1/4 of a day, so there are rules as to when not to add the extra day in some century years..

Answer 3

Because the time it takes the Earth to revolve around the sun isn't exactly 365 days, it is closer to 365 1/4. So every 4th year we add one day so we are at the same point in our orbit every year.

BTW, if a year is divisible by 100 but not 400, like the years 1900 and 2100, it isn;t a leap year.

Answer 4

The answers given are pretty much correct. The gregorian calendar (which most of the world uses these days) is a 400 year cycle that assumes a year that lasts 365.2425 days. There are 97 intercalar (leap) days every 400 years.

This is meant to approximate the mean tropical year (which is actually a tad shorter than 365.2425, closer to 365.2422 days) This is the amount of time it takes for the Sun to return to a particular right ascension. This is actually a tad shorter than a full orbit of the sun by about 20 minutes because of the precession of earth's rotational axis.

Answer 5

The calendar we use right now is called the Julius Calendar and it counts time based on the time our Planets revolves around the Sun and around its axle. We think the Earth evolved around itself in 24 hours. Actually its a little more than that. So that the year we know its 365 days, time the Earth evolves around the Sun. But in reality it evolves in 365 days and 8 hours. So every 4 year it adds up 24 more hours, one day, so it is added to the calendar in February.

Answer 6

Because the day isn't exactly 24 hours long. It's more like 24 hrs 11 min 14 sec (I believe) that every four years, the skipped time adds up to 24 hours and we stick it in the calender.

Edit
My bad. I just found the article I had read. What I should have said was the year was 365 days 5 hrs 48 min 49 sec long. I added when I should have subtracted somewhere else. Sorry

Answer 7

Its understood that the earth takes about 365.25 to orbit around the sun. After four years the quarters (0.25) make 1 complete day which is than added to February every four years... Why February in particular....??? I have no idea..

Answer 8

Because the year is NOT EXACTLY 365 DAYS long ... it's more like 365.25 days long, so we add that 'extra day' in February every four years to "make up for that extra quarter day."