SUN WILL RISE OVERHEAD IN SRI LANKA AREA AGAIN

 SUN WILL RISE

 OVERHEAD IN SRI

 LANKA AREA AGAIN

With the development of Astronomy, the people have understood the real facts of the relative motion between the Earth and the Sun. Modern understanding has disclosed that some of the facts accepted by man in old days are only unscientific concepts.

Within our solar system, the Earth completes one journey along an elliptical orbit around the Sun in 365.242 days (not either in 365 days or in 366 days) while the earth vibrates one round around its axis which is the line joining the North pole and the south pole, in 23 hours 56 minutes 4.1seconds (not in 24 hours). Even though we see the movement of our Earth around the Sun as a simple event, in reality it is a very complex astronomical event.

As we know, an ellipse has two important points called Poles positioned on the longer axis of the ellipse. The position of the Sun is centered at one of the two poles of the ellipse along which the Earth is moving. As a result the distance between the Earth and the Sun varies continuously during the Earth’s orbiting time called a year. During this variation, at one moment, the distance, say D, between the Earth and the Sun, reaches its lowest value, or the Earth takes the closest location to the Sun. This phenomenon is identified in Astronomy as ‘perihelion’. Using the past astronomical observations and mathematical calculations, this distance is 147.3 Millions of kilometers and the perihelion occurs on 4th January or a day close to 4th January. After this phenomenon, perihelion, D commences to increase with the time and D reaches its largest value, or the Earth takes the furthest location to the Sun in July. This phenomenon is identified as ‘aphelion’. Using the past astronomical observations and mathematical calculations, this distance is152.1 Millions of kilometers and the aphelion occurs on 4th July or a day close to 4th July.

An important fact to be considered in relation with the movement of the Earth is the continuous rotation of the Earth around its axis which is the line joining the North Pole and the South Pole of the earth. The Earth rotates one round around its axis in 23 hours56 min4.1seconds and this axis is inclined to the vertical of the plane of the Earth’s motion through an angle of degrees 23.5. These characteristics make the movement of the earth complex.

General understanding of most of people is that the Sun rises at 6am, Sun sets at 6pm and the Sun rises overhead at 12 noon on a daily basis. But in reality, the times of Sun rise, Sun set and overhead time show variation daily referred to any location on the earth. Therefore the main astronomical agency of any country of the world computes all of these astronomical data and makes the public aware of it. In Sri Lanka, the responsible institute for this task is the Meteorological Department. The astronomical division of the Meteorological Department, Colombo computes and prepares sets of information with times and dates of all the astronomical incidences related to our country.

According to the astronomical information provided by the Department of Meteorology for this year, 2023, the Sun will rise overhead to Sri Lanka land area during the period from 5th to 15th April.

Details are given below.