> There are 525,600 minutes in which unit of time?And the answer: a year. As fans of the musical RENT will recognize, there are 525,600 minutes in atypical year. However, in a leap year, that amount increases with the extra day,giving you an additional 1,440 minutes in your year.Photo credit: Alvesgaspar [https://commons.wikimedia.org/wiki/User:Alvesgaspar].For as long as humans have been looking to the night sky, we have been seekingways to quantify the passing of time. Some 30,000 years ago, ancient peoplesfirst recorded the phases of the moon, and ever since, recording time has been away by which humanity has observed the heavens and often stood to represent theprogress of civilization. The first recorded tool to measure time was the sundial, which measures theshadows during different parts of the day. However, it was quickly discoveredthat the shadows measure at different lengths for different parts of the year.The reasons for this difference were not well understood until after astronomersaccepted the fact that the Earth travels round the sun in an elliptic orbit, andthat the earth's axis is tilted at about 26 degrees. This variation from acircular 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 suchtheories is that the day's division into 12 hours comes from 12 being a factorof 60, and both the Babylonian and Egyptian civilizations recognized a zodiaccycle of 12 constellations. On the other hand, finger-counting with base 12 wasa possibility. The fingers each have 3 joints, and so counting on the jointsgives one "full hand" of 12.Learn more about the history of timekeeping here[https://www.factinate.com/things/43-fast-facts-time/].