Just think of how much you can get done with an extra day. But, you can't use that excuse this year because we got it!

The Romans added January and February to the calendar but ran into a problem — math and superstition. Here's why February became the odd month out.

That extra time known as a "sidereal" year must be accounted for somehow, the magazine says. Otherwise, seasons could be impacted. "If we didn’t account for this extra time, the seasons would ...

Slightly less than the 24 hours of a solar day (23 hours, 56 minutes, 4.1 seconds). Used in astronomy, sidereal means "when a star crosses the meridian" (the meridian is an imaginary circle around ...

Leap years account for the inaccurate measure of time on the 365-day calendar. Technically it takes 365.242190 days for the Earth to orbit the Sun, which is known as the "sidereal year," according ...