- One meaning of a "blood moon" is based on its red glow. This blood moon occurs during a total lunar eclipse. During a total lunar eclipse, Earth lines up between the Moon and the Sun. This hides the Moon from the sunlight.
- When this happens, the only light that reaches the Moon's surface is from the edges of the Earth's atmosphere. The air molecules from Earth's atmosphere scatter out most of the blue light. The remaining light reflects onto the Moon's surface with a red glow, making the Moon appear red in the night sky.
