A lunar eclipse occurs when the moon passes through the earth's shadow.This event can be seen during a full moon night.
A total lunar eclipse occurs when the sun, earth and moon are in a straight line and the earth blocks the sun's light from falling on the moon and casts a shadow on the moon.
The earth casts 2 kinds of shadows on the moon in which the larger shadow is known as the penumbra and the smaller darker shadow is known as the umbra.
As the moon continues along its path, it reaches the umbra.
At this point, all direct light from the sun is blocked by the earth, causing a total lunar eclipse.
During a lunar eclipse, sunlight is scattered through the earth's atmosphere. Blue light, which has a shorter wavelength, is scattered outward.
Red light, which has a longer wavelength is refracted towards the moon. This phenomenon makes the moon appear red during a full lunar eclipse!