SOLAR ECLIPSE
Since the moon revolves around the Earth all the times, why don’t we see solar eclipse during every moon’s revolution around the Earth?
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Before the question is answered, we should know how solar eclipses do happen. Solar eclipse is nothing but obscuring of the Sun due to the Moon coming in between the Sun and the viewer on the Earth during the course of revolving of the Moon and the Earth. As we all know that the Earth revolves around the Sun in a near circular path completing one revolution in about 365 days. The plane in which the Earth moves around the Sun is known as the Ecliptic.
At the same time the Moon also revolves around the Earth which is also a near circular path, completing on revolution in about 28 days, known as a lunar month. But the fact is that these two planes are inclined to each other at an angle.
For the Solar eclipse to occur, the Sun, the Moon and the Earth must come not only in one straight line but also these three bodies should be in one plane.
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Although the Sun, the Moon and the Earth come in one line every two weeks, once on a new Moon night and second time on the full Moon night, they seldom come in one plane during these events. This occurs two to maximum of five times in a year. Similarly, the Moon eclipse occurs when the Earth’s shadow falls on the Moon, which happens when the Earth comes in between the Sun and the Moon exactly.
This phenomenon takes place on a full Moon night and up to three times in a year. Generally the Sun eclipse and the Moon eclipse follow each other with a gap of 14 days. Another interesting fact about the Sun eclipse is that the events repeat each other after a time gap of 18.6 years, known as Saros cycle.
S.P.S. JAIN
Former Member, Engineering, Indian Railways, Greater Noida
THIS WEEK’S QUESTION
As in the case of humans, why don't we see dead sea creatures/animals floating in water?
T.S. KARTHIK, Chennai
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