Time is a big subject, it has a lot of importance in science.
Our days depend on the hands of the clocks, ie what time it is now, what time we have to do and so on.
But the question is, why does the new day start at 12 pm (according to the Gregorian or Julian calendar)?
The answer is not simple, but quite complicated, but it is clear that it happened with the help of ancient Rome.
To explain this first you need to understand AM and PM.
AM is an abbreviation of the Latin phrase ante meridiem, meaning before noon or before noon.
As for PM, it is an abbreviation of the Latin phrase post meridiem, which means after noon or after noon.
In ancient Egypt the day was divided into 24 parts or hours and the position of the sun in the sky was taken into account to determine the time.
This system is now called sundial, and since the sundial system could not work at night, it was necessary to use terms such as AMPM to determine noon and midnight. It was called something else).
The sundial was invented a thousand years before zero or 0, so the number 12 was used for the middle part of the day.
In ancient Rome, the AM and PM system was adopted and accordingly made 12, 2 groups of 12 hours, i.e. 12 hours of day and 12 hours of night.
In 159 BC a water clock arrived in Rome that could tell the 12 hours of the night.
Due to this, the Romans started the new day from midnight for business and social engagements, because at that time of the night engagements were negligible.
The Romans believed that changing dates in the afternoon would be too confusing, such as having lunch on Tuesday and returning to work on Wednesday, which would cause various problems.
Thus gradually it became a tradition and even now there is no change in it.