Lunar eclipse

The first total lunar eclipse in more than two years coincided with a supermoon.

A lunar eclipse occurs when the moon passes directly behind the earth into its shadow.
The earth, sun and the moon are either closely or perfectly aligned, with the earth in the middle. The earth’s shadow blocks sunlight from reflecting off the moon, thus resulting in an eclipse – partial or total.
A total lunar eclipse is dramatic, as the earth’s shadow (umbra) completely covers the moon. This can happen only when the sun, the earth and the moon are perfectly aligned.
Anything less than perfection will create a partial lunar eclipse or no eclipse at all. An eclipse does not appear every full moon because the orbit of the moon (around the earth) lies in a different plane than that of the earth (around the sun).

The moon’s orbit around the earth is distinctly elliptical. The point when the moon is closest to the earth is called Perigee and the point when it is farthest from it is called Apogee.
When a full moon occurs at its perigee, it is called a supermoon.
It is a rare event, as it has to satisfy two conditions – the moon must be closest to the earth and it should be a full moon. At this point, the moon is observed to be 30% brighter and appears 14% larger.

When the Moon is completely covered by Earth’s shadow it will darken, but doesn’t go completely black. Instead, it takes on a red color, which is why total lunar eclipses are sometimes called red or blood moons.
Sunlight contains all colors of visible light. The particles of gas that make up Earth’s atmosphere are more likely to scatter blue wavelengths of light while redder wavelengths pass through. This is called Rayleigh scattering, and it’s why the sky is blue and sunrises and sunsets are often red.
In the case of a lunar eclipse, red light can pass through the Earth’s atmosphere and is refracted – or bent – toward the Moon, while blue light is filtered out. This leaves the moon with a pale reddish hue during an eclipse.

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