20.03.11.Vesennee Equinox (Vernal Equinox) — one of the most unique natural phenomena, the essence of which, speaking the language of science, is to ensure that "at the time of the equinox center of the sun in its apparent motion along the ecliptic crosses the celestial equator."
Put simply, this day Earth rotating around its imaginary axis passing through the poles, while moving around the Sun, is in a position relative to the luminary that the sun's rays that carry heat, falling steeply to the equator. Sun moves from the southern to the northern hemisphere, and these days in almost all countries of the day is night. From 2010 to 2014 the vernal equinox occurs March 20.
Vernal and autumnal equinoxes are considered astronomical beginning of the respective seasons. The time interval between the two equinoxes of the same name is called a tropical year. This year today and adopted to measure time. In the tropical sun, approximately 365.2422 days. That's because of this "about" equinox each year account for different times of day, every year going forward about 6 hours.
Day vesennengo equinox begins the New Year in many nations and peoples of the Earth: Iran, Afghanistan, Tajikistan, Kazakhstan, Kyrgyzstan, Uzbekistan — almost all the countries of the Great Silk Road linked the new year with this natural phenomenon.
On this day, darkness and light are equally divided. In the old days, when there were calendars, spring, determined by the sun. It was believed that from this day begin renovation in nature: the first spring thunder, swelling buds on the trees, violent sprouting greenery.
The vernal equinox, and especially esteemed in pagan beliefs. It was believed that on this day in the annual cycle of spring, a symbol of the revival and rebirth of nature, replaces the winter.
As you know, when the sun moves from the northern to the southern hemisphere, the autumnal equinox occurs — 22 or 23 September.