How many days

[mulburger]

Officially how many days are there in a year,Is it 365 and a quarter????

[c00ky83]

To be pedantic - that's how long the Earth takes to orbit the sun, but not how many days in a year, which is 365 or 366.  The quarters you mention are collected up then given back in a leap year.

[Buenchico]

If you're looking for the time it takes for the earth to go round the sun, then to the nearest second, it's 365 days, 6 hours, 9 mins, 9 secs but that's the simple answer!

For the detailed answer, see here:
http://en.wikipedia.org/wiki/Astronomical_year

Chris

[MargeB]

Its roughly 365 and a quarter (by system). A leap year is every four years, except those years divisible by (I think) 200.

[THECORBYLOON]

Marge, almost correct, a year ending in "00" is a Leap Year only if it is a multiple of 400. The year 2000 was a Leap Year but 1900 wasn't 

[JudgeJ]

Readers should also bear in mind that the earth’s period of rotation is actually slowing down. There is evidence to suggest that the day was as short as 10 hours when the earth was first formed. There would then have been about 870 days in a year. Of course the earth may also have taken a different amount of time to revolve around the sun at that time, so these calculations are not always straightforward.

This slowing down is mainly caused by the “tidal” effect that the moon has upon the Earth’s rotation. The tidal effect caused by the moon’s gravitational “pull” causes the earth to “bulge” towards the moon. This happens to all celestial bodies but can be seen quite clearly on Earth by the twice daily movement of the sea known as the “tides”.

This daily distortion of the Earth’s shape is causing a gradual loss of its angular momentum (i.e. the energy it has by virtue of its spinning) and it is gradually, but very definitely, slowing down.

Eventually the Earth will become “tidally locked” with the moon and the same point on earth will always face the moon. This is because the Earth will take the same time to rotate once on its axis as the moon takes to revolve around the Earth.

This has already happened to the moon. The tidal effect of the earth upon the moon was far greater because the Earth is about 100 times more massive than the moon, so Tidal Locking of the moon occurred much sooner. The moon takes 28 days to revolve around the Earth and the same time to rotate once on its axis. As a result we always see the same face of the moon facing the Earth and it was not until the 1960’s when a spacecraft first revolved around the moon that photographs of the far side were taken.