© Harish Jharia
Lunar eclipse is a celestial constellation in which we are not able to see full view of the circular bright moon. The bright portion of the moon is partly visible and the remaining portion of the circular view remains dark.
There is another phenomenon that is called ‘the phases of moon’, in which the moon successively changes its shape, every day, from ‘full moon’ to ‘new moon’ in a fortnight and from ‘new moon’ to ‘full moon’ in the following fortnight. We are not going to discuss phases of moon in this article and will talk about it in another post on Discover Life.
What is lunar eclipse?
Let us discuss lunar eclipse in a common man’s language, without using scientific or astronomical terminologies. In lunar eclipse we are able to see the moon only partially and the rest of the portion becomes dark. It appears as if a portion of the moon has been chopped off from its main body.
Moon does not glow on its own and is only visible to us when sunrays fall on its surface. Full moon would be visible to us, in its full glow, when earth moves in-between sun and moon in a straight line and the earth does not block sunrays from falling on the moon.
Eclipse of moon commonly known as lunar eclipse takes place only on full moon nights. The formation of all the three celestial bodies that is sun, earth and moon remains the same as described under full moon conditions. Nevertheless, there is a little difference that the earth, in addition to being in between sun and moon in a straight line, also obstructs sunlight from falling on the moon surface, either partially or fully. As a result of this obstruction the moon becomes dark and eclipse takes place.
You may refer to the above illustration in which the sun, earth and moon are shown in a straight line. The paths of sunbeams are also shown emerging from the sun and obstructed by the earth. You may clearly see a dark portion behind the earth where sunrays are not penetrating. The illustration shows moon, positioned in the dark triangle behind the earth. This is the ‘full lunar eclipse’ condition when entire moon plunges in the dark tunnel. However when the moon is partially submerged in the dark tunnel, that condition would be called ‘partial lunar eclipse’.
Please also read "Moon Phases: How they Differ From Lunar Eclipse?" to know the difference between Lunar eclipse and lunar phases.