Why does a lunar eclipse occur during the full moon?

Answer 1

A lunar eclipse can only occur on the night of a full moon because of the position that the moon is in during a full moon. During a lunar eclipse, the Earth is positioned in between the moon and the sun exactly so that the Earth casts its shadow on the moon. During a full moon, the sun, Earth, and moon are lined up in the same way as a lunar eclipse, but the Earth is either too high or too low to cast its shadow on the moon. The only position at which the moon is a full moon is at that position since we can only see part of the lit face of the moon when the moon is at a different position around the Earth.