Carvings on a 12,000-year-old monument in Turkey appear to mark solar days and years, making it possibly the oldest solar ...

These graphics explain why Easter Sunday changes each year based on ancient interpretations of the solar and lunar cycles.

The next full moon is at 12:56 pm EST on Monday, May 12 and is known as the Flower Moon. Here is a look at all the full moons ...

Julius Caesar was believed to have messed up the months in a year, but was trying to fix the solar calendar, resulting in one ...

Due to the complexities of the various types of calendars, the date of Easter can be as early as March 22 and as late as April 25. Here's why.

Year-round schools have long been thought to potentially improve academics by reducing the length of summer break. Research ...