Q: How did Sumerians invented the Calendar
Answers
Answer:
The Sumerian calendar was lunisolar, meaning that it was organized around the three obvious natural cycles: (1) the unit of the day based the regular rising and setting of the Sun due to the Earth’s rotation; (2) the lunar month, the period called the lunar cycle which is the transition of the Moon through its cycle of phases back to the arbitrary starting phase; and lastly (3) the solar cycle which is the change throughout the year of the Sun’s rising and setting positions, and the change in the Sun’s elevation above the horizon throughout the year.
What the Sumerians would have seen, because they lived in latitudes slightly north of the equator, is the Sun rising in the East further and further North towards the June Solstice when it achieves a sunrise that is furthest north from due east. Afterwards the Sun rises gradually more to the south-of-east until it reaches its greatest distance south from due east around the December Solstice. The sunset patterns are the same (north towards June solstice and south towards December solstice) though taking place on the western horizon.