The way we divide the day into hours and minutes, as well as the structure and length of the calendar, thanks in large part to the pioneering development of Ancient Egyptian .
Because Egyptians' lives and agriculture depend on the annual flooding of the Nile , it is important to determine when such floods begin. Early Egyptians pointed out that the beginning of the akhet (flood) occurred when a spiral of a star they called Serpet (Sirian). It is calculated that the stellar year is only 12 minutes older than the average regression that affects floods, which only 25 days of difference in recorded history throughout ancient Egypt.
3 Egyptian calendar
Ancient Egypt was run according to three different calendars.
The first is the lunar calendar based on 12 lunar months, each month starts from the first day when the old crescent moon is no longer visible in the east at dawn. (This is the most unusual, as it is well known that other civilizations of that era started several months with the first setup of crescent !) The thirteenth month was inserted to keep order of Serpet's spiral upward connection. This calendar is used for religious festivals.
The second calendar is based on the observation that there are usually 365 days between the spiral of the snake. This civilian calendar is divided into twelve months of 30 days and five epagomenal days are attached at the end of the year.
This additional five days are considered unlucky. Although there is no conclusive archaeological evidence, detailed backtracking calculations show that the Egyptian civil calendar dates back to about 2900 B.C.
This 365-day calendar is also called the Wandering Calendar, from the Latin name annus vagus, as it slowly becomes out of sync with sun year . (Other wandering calendars include Islamic years.)
dates at least to the third calendar in the 4th century BC to match the moon cycle with civilian years. It is based on 25 civilian years that are approximately equal to 309 lunar months.
leap year
Early Ptolemaic dynasty (Kanopus Act 239 BC) tried to reform the calendar to include leap year, but priest was too conservative to allow such changes.
This predates the Julian reform introduced by Julius Caesar at the suggestion of Alexander astronomer Sosigenese. However, after Rome General (soon emperor) Augustus defeated Cleopatra and Anthony , reform did come.
Years, the Roman Senate issued a decree that the Egyptian calendar should include leap years, but the actual calendar changes did not occur until 23 BC.
months, weeks and decades
months of the Egyptian calendar are further divided into three parts, called "ten years", each part has 10 days. The Egyptians noticed that the spiral rise of certain stars such as Sirius and Orion matched the first day of 36 consecutive decades and called these stars decans.
On any night, a series of 12 intervals will be seen rising and used to calculate the number of hours. (This division of the night sky was later adjusted according to earlier days, very similar to zodiac zodiac
zodiac twelve zodiac twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve twelve tw The sunshine in summer is longer, so it is longer than the daytime in winter. It was the Egyptians who first divided the day (and night) into 24 time hours.
Egyptians used shadow clocks to measure the time of day, which was the predecessor of the easier-to-identify sundial today. Records show that early shadow clocks were based on shadows across four markers, representing hourly periods starting from two hours of the day. At noon, when the sun is at its highest, the shadow clock will reverse and count down to dusk.
A modified version that uses a rod (or gnomon) and indicates time according to the length and position of the shadows survived from the 2000 B.C.
The problem of observing the sun and stars may be the reason why the Egyptians invented water clock or "clepsydra" (the leaker in Greek ). The earliest extant examples come from the Karnak Temple, dating back to the 15th century B.C.
Water drops into a lower container through small holes in a container. The markers on either container can be used to record the elapsed number of hours.
Some Egyptian crepes have several sets of markers that can be used at different times of the year to maintain consistency with seasonal time. The design of 国六国 was later adapted and improved by the Greeks.
The impact of astronomical science on minutes and hours
Due to the war of Alexander the Great, a large amount of astronomy knowledge was exported from Babylon to India, Persian , Mediterranean and Egypt. The great Alexandria and its impressive library were both established by the Ptolemy Greek- Macedonian family and served as an academic center.
time is almost useless for astronomers, around 127 AD, Nicea working in the great city of Alexandria proposed to divide the day into 24 equinox hours. These vernal equinox times are called so because they are based on the equal length of day and night at the equinox points, dividing the day into equal time periods.
(Although he made conceptual progress, the average man continued to use time for more than a thousand years: Europe converted time to the vernal equinox when he developed a weight-driven mechanical clock in the 14th century.)
Another Alexander philosopher, Claudius Ptolemeus, further refined the division of time, who divided the vernal equinox into 60 minutes, inspired by the weights and measures used by ancient Babylon.
Claudius Ptolemaeus also compiled a large catalog of more than 1,000 stars of 48 constellations and recorded the concept of his universe orbiting the Earth.
With the collapse of The Roman Empire , it was translated into Arabic (827 AD), and later into Latin (12th century AD). These star tables provide astronomical data used by Gregory XIII in 1582 reform Julius.
