Lunar Eclipse

A lunar eclipse occurs when the Earth blocks out the light from the sun on the moon. The Earth eclipses the sun and therefore casts a shadow onto the moon. This can only occur when the Sun Earth and the Moon are in line with one another, the Earth being in the middle. As there are different types of Solar Eclipses there are also different types of Lunar Eclipses. Firstly a penumbral eclipse is when the Moon passes through the Earths penumbra which is the fuzzy region. This is related to the unit of light that an object casts a shadow which has an umbra the dark region and a penumbra the fuzzy region around the umbra. The penumbra causes a darkening of the moons surface. A partial lunar eclipse is when only a little portion of the Moon enters the umbra. A total lunar eclipse is when the moon travels completely in the Earth's umbra. This is when the entire moon is dark. A selenelion eclipse occurs when both the sun and the moon can be observed at the same time. This only occurs right before sunset or after sunrise. Both bodies will appear in the sky at different locations.
Once the moon enters the Earth's umbra it does not disappear. This is becasue of the refraction of sunlight by the Earth's atmosphere. Again this is related to the subject on light. Only if Earth had no atmosphere would the Moon disappear as it enters Earths umbra.
Every year there are usually two partial lunar eclipses. Unlike a solar eclipse where there is a certain area one must be to experience it a lunar eclipse can be seen from anywhere where it is night on Earth.
The next partial eclipse of the Moon is projected to occur on the 31st of this month. While the next total eclipse of the Moon is projected to occur on December 21,2010.