Here are the figures that I left out of other pages to stop it looking too complicated. For those of you who want to know the details - this is the place. To find out what the terms used here mean look for the relevant page on the Site Index page.

Unit | Duration |

How long is a year? |
A tropical year is 365.242199 days UT which is equal to365 days, 5 hours, 48 minutes and 45 seconds. A sidereal year is 365.256366 days UT which is equal to365 days, 6 hours, 9 minutes, and 9.5 seconds. An anomalistic year is 365.259636 days UT which is equal to365 days, 6 hours, 13 minutes, and 33 seconds. |

How far has the Gregorian calendar drifted since it was decreed in 1582? | 2 hours, 59 minutes, 12 seconds. |

When will the Gregorian calendar be one whole day out? | The year 4909 AD. |

How many lunar months are there in a year? | 12.368267 |

How long is a lunar month? | Its average length is 29 days, 12 hours, 44 minutes, and 2.9 seconds, or 29.530589 days. |

How long is a second? |
The second is the duration of 9 192 631 770 periods of the radiation corresponding to the
transition between the two hyperfine levels of the ground state of the caesium 133 atom.
Well you wanted to know! |