Why are there 24 hours in a day? Detailed answer

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Why are there 24 hours in a day? Detailed answer

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Why in the day 24 hours?

The only reason why a day consists of 24 hours is that people have decided that this is the most convenient way for them to measure time. There is nothing in nature that determines the duration of hours, minutes and seconds - the units that we use when talking about time. However, the situation is different when it comes to the time period corresponding to what we call a day, or a day.

The duration of a day corresponds to the time interval during which the Earth makes a complete revolution around its axis from west to east. This period of time is always the same. You may be surprised to learn that there are actually not 24 hours in a day, but much less. Scientists have calculated the exact time of the complete revolution of the Earth from the stars. The principle of calculation is quite simple. It consists in the fact that scientists detect the moment at which a certain star is above the meridian - an imaginary line stretching from the North Pole to the South, strictly perpendicular to the direction of the Earth's rotation. This moment is considered the beginning of the day. Their end comes at the second when the same star again appears above the same meridian.

The interval of time measured in this way is called an astronomical or sidereal day and is equal to 23 hours 56 minutes and 4,09 seconds. 366 astronomical days make up one year. A year is the length of time it takes the Earth to complete one revolution around the Sun. Since it is customary to assume that there are 24 hours in a day, the result is that there are 365 1/4 days in a year.

For convenience, the calendar is arranged in such a way that out of every four years, one year is called a leap year and consists of 366 days, and the other three - of 365 days. However, time was not always measured in this way. In ancient Greece, for example, the length of the day was determined by the time elapsed between dawn and sunset. Night hours were simply not taken into account. However, the ancient Romans began to count time in the same way as we do: from midnight to midnight. Before the clock was invented, both day and night were divided into 12 equal intervals. However, such a system was inconvenient, since the length of day and night at different times of the year is not constant.

Everyone knows that in summer the day is longer than the night, while in winter it is the other way around. The first who divided the entire day into 24 parts equal to one hour were the same ancient Romans. Today, almost everywhere on the globe, time is measured in this way.

Author: Likum A.

Random interesting fact from the Great Encyclopedia:

When was the umbrella invented?

We are used to using an umbrella to protect us from the rain. But in reality the umbrella was not invented for this purpose. Its first purpose was protection from the sun's rays! No one knows the inventor of the umbrella, which was used already in very ancient times.

It is believed that the Chinese were the first to make an umbrella. This was back in the XNUMXth century BC! It is known that the umbrella was used in ancient Egypt and Babylon as a shield from the sun. An interesting fact is connected with its use - it has become a symbol of power. In ancient times in the Far East, only a member of the royal family or high-ranking courtiers could use an umbrella.

In Europe, the inhabitants of Ancient Greece were the first to use an umbrella. However, there is an opinion that the first Europeans who used an umbrella to protect themselves from the rain were the Romans. In the Middle Ages, the use of the umbrella practically ceased. It then reappears in Italy at the end of the sixteenth century. Again, it was seen as a symbol of power.

Around 1680, the umbrella appeared in France, and later in England. In the eighteenth century, the umbrella was used to protect against rain almost throughout Europe. During all this time, the shape of the umbrella has changed slightly, they have become only a little lighter. Colored women's umbrellas began to be made only in the XNUMXth century.

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