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| Sunday, 19 March 2006 |
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Junior Observer |  |
| News Business Features Editorial
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March 21 - Vernal Equinox March 21st is a very special day in the year. Some of you may have learnt in class why this day is so special. On March 21, the Sun is directly above the equator, and day and night are of equal length in the tropics. This happens only on two days of the year - on March 21 and September 22 or 23. These two days are called the equinox. March 21 is called the Vernal or Spring Equinox, because this day marks the beginning of spring in the northern hemisphere. September 22/23 is the Autumnal Equinox. Autumn in the northern hemisphere begins after this date when the Sun crosses the equator, in its southward journey. The Sun crosses the equator on March 21 on its northward journey. What do we mean when we say the Sun crosses the equator? Although the Sun doesn't really move, it seems to be moving because the Earth is constantly on the move. The Sun seems to move between the two tropics which are 23.5 degrees north and south of the equator. The latitude 23.5 degrees north of the equator is the Tropic of Cancer, and the 23.5 degrees south latitude is the Tropic of Capricorn. As the Sun is placed between these two tropics, it "crosses" the equator twice, once on March 21, going north, and again on September 22/23, going south. This twice a year happening is called the equinox. With the movement of the Earth, and the equator facing the Sun directly on March 21, Sri Lanka is facing the Sun. That is why it is getting hotter, and the days are getting longer. We have more hours of daylight now, unlike in December when the Sun is far away from us, facing the southern hemisphere. The Sun will be facing Sri Lanka from about April 5 to about April 9. In Iran, March 21 is the beginning of a new year. They celebrate the dawn of a new year on March 21 and this new year festival is called Nouruz. - Sumana Saparamadu.
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