# 525,600 Minutes

There are 525,600 minutes in which unit of time?

As fans of the musical RENT will recognize, there are 525,600 minutes in a typical year. However, in a leap year, that amount increases with the extra day, giving you an additional 1,440 minutes in your year.

For as long as humans have been looking to the night sky, we have been seeking ways to quantify the passing of time. Some 30,000 years ago, ancient peoples first recorded the phases of the moon, and ever since, recording time has been a way by which humanity has observed the heavens and often stood to represent the progress of civilization.

The first recorded tool to measure time was the sundial, which measures the shadows during different parts of the day. However, it was quickly discovered that the shadows measure at different lengths for different parts of the year. The reasons for this difference were not well understood until after astronomers accepted the fact that the Earth travels round the sun in an elliptic orbit, and that the earth's axis is tilted at about 26 degrees. This variation from a circular orbit allows us to work out the difference between "clock time" and "sundial time."

There are various theories about how the 24-hour day developed. One of such theories is that the day's division into 12 hours comes from 12 being a factor of 60, and both the Babylonian and Egyptian civilizations recognized a zodiac cycle of 12 constellations. On the other hand, finger-counting with base 12 was a possibility. The fingers each have 3 joints, and so counting on the joints gives one "full hand" of 12.