The Sumerians are thought to have formed the first human civilization in world history. They lived in southern Mesopotamia, between the Tigris and Euphrates Rivers in the Middle East. Cradle of Civilization. Many historians think that cities and towns were first formed in Sumer around 5000 BC.
At noon, on March 21 and September 23rd are the vernal and autumnal equinoxes. The sun is directly overhead at the equator at these times. On June 22nd is the summer solstice, in the Northern Hemisphere. The sun is at the 23.5 degrees Northern latitude.
And if you want the precise astronomical moment when spring starts (which is when the sun crosses the equator and heads north), that will be at 10.45pm on that date. In 2015, the date will be easy to remember because March 20 also happens to be when we will experience Europeâs biggest solar eclipse since 1999. Spring will last until the Summer Solstice, which in 2015 will be on June 21. That will be the longest day and signal the start of summer. From that point, the days begin to get shorter until daylight and night are once again approximately of equal length on the Autumnal Equinox on September 23.