Why Is A Day 24 Hours Long?

Have you ever wished that a day had more than 24 hours? Seriously, sometimes it seems like there just isn’t enough time in a single day to achieve everything we want. At those times, we might curse the person that invented the 24 hour day, but many of us probably don’t even know who that is.

Was it a single person? How did it come to be? The answer has to do with stars. While the number 24 might seem arbitrary, it is not, there is much more meaning hidden behind it, and we will try to explain it in this article.

The Ancient Egyptians Started It All

There is a lot of historical significance behind the number 24. The first people that started dividing days into 24 parts were the ancient Egyptians. They originally divided the day into three large parts. The first part lasted for 10 hours, and it was the daylight part. Then there were 12 hours of nighttime. And finally, there were two hours of twilight, one appeared at the beginning of the day, while the second one happened at the end of each day.

The person that brought order into everything and introduced the 24-hour day as we know it today was Hipparchus, a Greek astronomer. He used equinoxes and measured 12 hours of daylight and 12 hours of nighttime. All of these hours were evenly spaced out. This marked the start of the 24-hour day, and it happened in the 2nd century B.C. Hipparchus studied the way the planets rotated constantly, and eventually managed to find the axial precession of the equinoxes.

This precession is the change in direction in the orientation of the rotational axis of a planet or a different astronomical body. The precession of the Earth is called the precession of the equinoxes, and it allowed for a more effective method of measuring an hour.