At new moon, earth may pass through moon?s shadow so that

parts of the sun will be obscured to the eyes on the earth.

Earth e being much bigger than moon, whole of it cannot pass

through the umbra. But as the points on the earth will fall

within this umbra, a total solar eclipse occurs. At places

which pass through penumbra, a partial solar eclipse occurs.

Eclipses do not occur regularly even though the

earth comes between the moon and the sun at every full moon.

It is because of two reasons:-

(1) The moon?s obit is inclined to that of earth at an angle

of about 50 .

(2) The earth?s orbit being elliptical, the distance of the

earth from the sun is different at different positions of

the orbit, due to which the size of the shadow changes.