A "Blood Moon" occurs during a total lunar eclipse when the Earth comes directly between the Sun and the Moon, blocking most sunlight from reaching the Moon's surface. However, some sunlight passes through the Earth's atmosphere, which filters out shorter wavelengths (like blue) and bends the longer red wavelengths toward the Moon, giving it a reddish color resembling blood. This reddish appearance is due to a phenomenon called Rayleigh scattering, the same effect that causes red sunsets and blue skies.
Key Causes of a Blood Moon:
- The Sun, Earth, and Moon align perfectly (or very closely), with Earth in the middle.
- Earth blocks direct sunlight from hitting the Moon.
- Earth's atmosphere refracts and filters sunlight, allowing only longer wavelengths (red, orange) to reach the Moon.
- The Moon appears red, orange, or yellow, especially when fully inside Earth's darkest shadow.
This red tint can vary depending on Earth's atmospheric conditions, such as dust or clouds, which can make the Moon appear more or less red during the eclipse.
