Why day 24 hours
at day 24 hours
We live in a decimal world. Decimal system covers everything from binary functions of computers to the number of delivery, which you get at the store. So why is the standard earth day lasts ten o'clock? We have to say thanks for that to the ancient Egyptians.
As soon as civilization shifted from a nomadic hunter-gatherer communities to farming communities, people have found the need to consider their property and objects around them. (If you leave in the morning in a pasture with five goats, and return in the evening with three, and you can not tell the difference - your bad deeds). The concept of written language still just in its infancy, and so people have learned to count as do young children - with the help of his ten fingers.
Egyptian hieroglyphics 3000 BC indicate that while using the decimal system. So why do they move their clocks at twelve-? Many believe that the duodecimal system emerged from the counting system, which the Egyptians inherited from the early Sumerian culture that did not use a finger to an account, and each individual joint. If you open the left hand, and will use the tip of your thumb to touch each of the three joints on four of your fingers, you end up with twelve. To measure time by this method, the Egyptians divided the day to the twelve half - or more precisely, a ten-day, two hours morning and evening twilight, and a twelve-hour night. And the watch itself Egyptians was based on the motion of the sky. They tracked a series of thirty-six small constellations, known as the "deans" who consistently rose above the horizon approximately every forty minutes. Sunrise each new dean marked the beginning of a new hour. Beginning of a new decade - the Egyptian period of ten days - reckoned from the emergence of a new dean in the eastern sky just before sunrise.
In the ninth dynasty (around 2100 BC), the Egyptians perfected their solar calendar surveillance system for the regular appearance of these stars, and created a generalized annual calendar. Thirty-six decades have made three hundred and sixty days of the new calendar. The new system proved to be accurate enough to accurately predict the annual flooding of the Nile during the rising of Sirius, even despite the fact that the actual length of the hours varied according to the season. "There were tables set up, which helps people determine the time at night by means of observation of the deans. What is surprising - such tables were even found inside the burial sarcophagi, probably to the dead could also determine the time, "says Dr. Nick Lomb, curator of the Sydney Observatory. And while the new calendar has allowed to determine the time with great ease, laid the foundation of its flexibility in hours makes this system useless for the Greeks - they needed a day with segments of equal length. Hipparchus, who is considered the greatest astronomer of antiquity, is credited with the transformation of the Egyptian stellar hours a standardized equinoctial clock that we use in our day, and in which each period of light and dark on the equinoxes are divided into twelve equal intervals.