A lunar eclipse is when the Earth's shadow prevents light from reaching the Moon's surface. Lunar Eclipse can only occur during a full moon. Full moons occur after the moon completes one full orbit around the Earth or every 29.5 days.
Lunar Eclipses only happen every once in a while because the Moon's tilt aligns with the Earth. Resulting in the Moon appearing in Earth's shadow. When the Earth eclipses the Sun it forms two types of shadows; the penumbra and a smaller shadow called the umbra.
Types of Lunar Eclipses
A total Lunar Eclipse is when the Sun, Earth, and Moon are in perfect alignment. The Moon is in Earth's umbra shadow. During a total lunar eclipse, the Moon appears to be a sunset red or dark brown. Total Lunar Eclipses are most commonly known by the name blood moon. During a Total Lunar Eclipse, the Moon turns red because blue light is scattered outward resulting in only the red wavelengths being refracted inward creating the illusion that the Moon is red. However, sometimes during a total lunar eclipse, the moon can appear black because volcanic ash can block out enough light in the Earth's atmosphere.
A partial Lunar Eclipse happens when the Earth, Moon, and Sun don’t perfectly align. Only a portion of the moon goes into the earth's umbra. During a personal eclipse, a slight shadow is on the moon.
Penumbral Lunar Eclipse is when the moon passes through Earth's penumbral shadow. However, the moon during a penumbral eclipse is only slightly darker than usual.