Signed, Todd - Villa Rica Elementary. Human beings seem to be fascinated with the passage of time. Nowadays we have clocks, wristwatches, and day-planners to help us keep track of our lives but it wasn't always so. In the past, calenders helped schedule festival seasons, religious holidays, and the harvesting of crops.
Calenders are simply means of organizing and recording the passage of time on a grand scale.
While a clock measures hours and minutes, a calender measures time in units of years and centuries. Most historical and present day calenders are based upon astrological movements of the stars, planets, and the moon. Even though we have more precise measuring devices, astrology remains the standard for making calenders today. While there are many methods for making calenders, there are only 3 basic types. The first type, a solar calender like the one we use in the United States, measures the time it takes the earth to orbit the sun.