Longer evenings and hotter days!
Have you noticed how the evenings are getting longer these days?
There is daylight until long after 6 o’clock unlike in December and
early January when it got dark even by 5.30 pm. The days get shorter and
shorter and the nights longer and longer from late November. The
opposite is happening now. Why is this? It is because the Sun is getting
closer to Sri Lanka.
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September 23 is called the autumnal equinox. |
Some of you must have learned about the movement of the Sun and the
equinoxes in geography lessons. Let me explain for the benefit of those
who haven’t learned about this as yet.
The Sun seems to move between the two tropics - the Tropic of Cancer
in the northern hemisphere and the Tropic of Capricorn in the Southern
hemisphere. The two tropics are 23.5 degrees north and south of the
equator.
On March 21 the Sun was directly over the equator and is now slowly
moving north towards the Tropic of Cancer. And as it moves north, the
Sun is getting closer to Sri Lanka, which lies between 5.4 and 9.4
degrees north of the equator. That is why the evenings are longer. There
is more daylight now and the days are getting hotter and hotter.
Today (April 5) the Sun will be directly overhead the southern most
towns and villages of our country and tomorrow the Sun would have moved
a little further north and be over Hikkaduwa.
It’ll be over Maggona, the following day. When I say over Hikkaduwa,
I don’t mean only over that town, but over all towns and villages and
forests on that latitude, and over all countries and seas that lie on
the same latitude. On April 8, the Sun will be over Wellawatte and then
gradually over Katana, Bangadeniya, Navakkadu, Jaffna and finally over
Kankesanturai on April 16.
| ''It is the
movement of the Sun to the north and south, that brings about
the change in seasons. '' |
Each day the Sun will move slightly northward until it reaches the
Tropic of Cancer on June 21. From June 22 the Sun will begin moving
south and again pass directly over Sri Lanka between August 28 and
September 9 and reach the equator on September 23.
These two days March 21 and September 23 when the Sun is directly
overhead the equator are called equinoxes. March 21 is the spring or
vernal equinox because that marks the beginning of spring in the
northern hemisphere.
|
March 21 is the spring or vernal equinox. |
September 23 is called the autumnal equinox as it marks the beginning
of autumn in the northern hemisphere. On these two days, the equinoxes
day and night are the same length in the tropics, that is, in lands and
seas that lie between the two tropics. The time between sunrise and
sunset will be exactly 12 hours.
The ancient Egyptians, the Babylonians, the Persians and the Indians
were aware of the equinoxes. The Indian astrologers called the equinox
Vishuva, the Sun’s journey north was Uttaraayana and the southward
journey Dakshinaayana. The Sun is now in its Uttaraayana.
It is this movement of the Sun, to the north and south, that brings
about the change in seasons.
When it is spring time in the northern hemisphere as it is now, it is
autumn in the southern hemisphere in countries like Australia, New
Zealand, South Africa, Argentina and Chile. June 21 is mid summer in
Europe, America, China, Russia and mid winter in those lands in the
southern hemisphere.
The spring equinox (March 21) is New year’s day in Iran. The ancient
Persians were well aware of the movement of the Sun and the day when
hours of daylight and darkness were equal. The Iranians call the new
year festival celebrated on March 21 Nourux.
The Jews celebrate their new year at the autumnal equinox September
23.
- Sumana Saparamadu |
