What causes a lunar eclipse?

A lunar eclipse occurs when the Earth comes directly between the Sun and the Moon, causing the Earth's shadow to fall on the Moon. This alignment happens only during a full moon, when the Moon is on the opposite side of the Earth from the Sun. Because the Earth blocks sunlight from reaching the Moon, the Moon appears darkened or even takes on a reddish hue during the eclipse. There are different types of lunar eclipses depending on how the Moon passes through Earth's shadow. A **total lunar eclipse** happens when the entire Moon passes through the Earth's umbra, the darkest part of its shadow. During this time, the Moon often appears reddish due to sunlight refracting through Earth's atmosphere—a phenomenon called “Rayleigh scattering.” A **partial lunar eclipse** occurs when only part of the Moon enters the umbra, and a **penumbral lunar eclipse** happens when the Moon passes through the Earth's penumbra, a lighter outer shadow, causing only a subtle darkening. In summary, a lunar eclipse is caused by the Earth blocking sunlight from reaching the Moon, resulting in the Moon being temporarily darkened or colored as it moves through Earth’s shadow. This beautiful celestial event can be observed from anywhere on the night side of Earth when the alignment occurs.