What occurs at a full moon when Earth is directly between the moon and the sun?

• A. Solar eclipse
• B. Lunar eclipse
• C. Phases of the Moon
• D. Revolution

Answer: (B)

A lunar eclipse. When the Moon is full, it sits opposite the Sun, and if Earth lies directly between them, Earth blocks sunlight from reaching the Moon. The Moon moves into Earth's shadow, so its bright illumination is temporarily cut off. If the alignment is exact, you get a total lunar eclipse where the Moon can look reddish due to sunlight filtering through Earth’s atmosphere; if only part of the Moon enters the shadow, it’s a partial eclipse, and if only the outer shadow is touched, it’s a dim, penumbral eclipse. This is different from a solar eclipse, which occurs when the Moon is between the Sun and Earth at or near new Moon, and different from the usual lunar phases, which are just the changing appearance of the lit portion of the Moon.