Eclipses are important astronomical phenomena. Let's try to understand how they occur. When the sun, the moon and the earth are in a straight line the chances are you may see one of the following
- A lunar eclipse or
- A solar eclipse.
The first case occurs when the earth is between the sun and the moon. Now, the earth prevents the sun's light from falling on the moon and hence the moon is plunged into darkness. If only a part of the moon's face is eclipsed by the earth's shadow, then the eclipse is partial. If the whole of it is eclipsed, then the eclipse is termed a total lunar eclipse. A lunar eclipse always occurs on a full moon day. Why is it so? Well, you see, on a full moon day, the sun and the moon are in opposite directions. And that is exactly the case with lunar eclipse too. (i.e. for a lunar eclipse to occur, the sun and the moon have to be on opposite sides of the earth and this condition characterizes a full moon day.)
A solar eclipse results when the moon comes in between the earth and the sun thus blocking the sun from the earth. Again, this can be a partial eclipse or a total eclipse (both of them being defined on the same lines as for lunar eclipse.). Sometimes it may so happen that the central portion of the sun is eclipsed while the outer portion is visible. This gives it a ring-like appearance. Hence its called annular eclipse. All solar eclipses occur on a new moon day.
Let's go deeper and find out how exactly eclipses occur.