How many hours are there in a day? This is known to all - 24 hours. But why did that happen? Let's take a closer look at the history of the appearance of the basic units of time and find out what a day is, how many hours, seconds and minutes are in a day. And also let's see whether it is worth tying these units exclusively to astronomical phenomena.
Where did the day come from? This is the time of one revolution of the earth around its axis. With little knowledge of astronomy, people began to measure time in such ranges, including in each light and dark time.
But there is an interesting feature. When does the day begin? From the modern point of view, everything is obvious - the day starts at midnight. People of ancient civilizations thought differently. It is enough to look at the very beginning of the Bible in order to read in Genesis 1: "... and it was evening, and it was morning
day: one
day ." Day began with the
sunset. There is a certain logic to this. The people of that time were guided by
daylight hours. The sun has set, the day is over. Evening and night is the next day.
But how many hours are there in a day? Why was the day divided by 24 hours, because the decimal system is more convenient, and much more? It would be 10 hours in a day, for example, and in every hour 100 minutes, would something change for us? Actually, nothing but numbers, on the contrary, would even be more convenient to perform calculations. But the decimal system is far from the only one used in the world.
In ancient Babylon , a six-decimal system of counting was used. And the bright half of the day was well divided in half, 6 hours each. Total in 24 hours was obtained. This fairly convenient division was taken from the Babylonians and other nations.
The ancient Romans counted time even more interesting. The countdown began at 6 a.m. So they thought from this moment on - the first hour, the third hour. Thus, it can easily be considered that the “eleventh hour workers” commemorated by Christ are those who begin work at five in the evening. Really late!
At six o'clock in the evening the twelfth hour arrived. That's how many hours in a day were counted in ancient Rome. But there still remained the night hours! The Romans did not forget about them. After the twelfth hour, the night watch began. Attendants were replaced at night every 3 hours. Evening and night time was divided into 4 guards. The first evening guard began at 6 pm and lasted until 9. The second, midnight, lasted from 9 to 12 hours. The third guard, from 12 a.m. to 3 a.m., ended when the roosters sang, which is why it was called - "roosters singing." The last, fourth guard, was called "morning" and ended at 6 in the morning. And it all started all over again.
The need to divide the clock into parts also appeared much later, but then they did not depart from the six-decimal system. And then they divided the minute into seconds. True, later it turned out that relying solely on
astronomical observations to determine the duration of seconds and days is impossible. Over a century, the length of the day increases by 0.0023 seconds - it seems to be very small, but enough to get confused about the number of seconds in a day. And this is not all the difficulties! Our Earth does not make one revolution around the Sun in an equal number of days, and this also affects the solution of the question of how many hours are in a day.
Therefore, to simplify the situation, the second was equated not with the motion of celestial bodies, but with the time of the occurrence of processes inside the cesium-133 atom at rest. And to match the actual state of affairs with the Earth’s revolution around the Sun twice a year - December 31 and June 30 - 2 extra leap seconds are added, and once every 4 years - an additional day.
Total it turns out that in days 24 hours, or 1440 minutes, or 86,400 seconds.