Every year at the end of the second decade of March, according to the CE calendar, spring begins in the Northern Hemisphere and autumn begins in the Southern Hemisphere.
Well, in recent years the duration of spring has decreased, but the spring equinox, or equinox, occurs between March 19 and 21 each year. This is the time when the sun moves north over the equator. passes
Our Earth tilts to one side in its orbit around the Sun, resulting in more or less sunlight and heat reaching our planet directly at certain times of the year.
On the occasion of Rabi’i equinox, since the sun is above the equator, the sunlight reaches almost everywhere in the world in the same amount. That is, the length of the day and night are also almost the same on this occasion, i.e. 12, 12 hours.
This series of day and night length continues for a few days after Rabi’i equinox. This year, Rabi’i equinox will begin on March 19 (March 20 at 8:06 a.m. Pakistan time). Similarly in September. Also occurs when the equinox begins, or the September equinox. The length of day and night become equal in March and September (but not in some regions).
The word equinox means equal night.
After Rabi’i Equinox, the days start getting longer and the nights shorter in the Northern Hemisphere and this process continues until the summer solstice.
It should be noted that the month of Cancer or the summer solstice begins in June, while the month of Ras al-Jadi or the winter solstice begins in December. Ras al-Jadi begins with the shortest day of the year, after which the length of the day begins to increase.
In ancient times, the seasons were estimated from Rabi’i moderate, Kharifi moderate, Cancer and Ras al-Jadi. It should be clear that it is reversed in the southern hemisphere, that is, the length of the day will decrease and the night will increase.
