During a lunar eclipse, the Earth, Moon, and Sun are in a specific alignment where Earth casts its shadow onto the Moon.
The Earth is positioned between the Sun and the Moon, slightly closer to the Sun and is is crucial for the Earth's shadow to fall onto the Moon.
The Moon is positioned directly opposite the Sun in Earth's sky. This full moon phase is necessary for the eclipse to occur.
Due to the slight tilt of the Moon's orbit, it often passes through the Earth's penumbra or umbra , depending on the type of eclipse. The Sun is positioned directly behind the Earth from the Moon's perspective. It acts as the light source that Earth blocks, casting its shadow onto the Moon.