1. Sunlight through the Earth's atmosphere: During a lunar eclipse, the Earth is positioned directly between the sun and the moon. Sunlight passes through the Earth's atmosphere on its way to the moon.
2. Scattering of shorter wavelengths: The Earth's atmosphere scatters sunlight. Shorter wavelengths of light (blue and green) are scattered more effectively than longer wavelengths (red and orange).
3. Red light reaches the moon: As a result, most of the blue and green light is scattered away, leaving primarily the longer wavelengths of red and orange light to pass through the atmosphere and reach the moon. This red light is then reflected back to Earth, giving the moon its reddish hue.
Think of it like this: Imagine shining a white light through a glass of water. The light appears blue when viewed from the side because the water molecules scatter blue light more than red light. Similarly, the Earth's atmosphere scatters blue light, leaving the red light to illuminate the moon during a lunar eclipse.
Factors affecting the redness: The intensity of the red color can vary depending on the amount of dust and clouds in the Earth's atmosphere. More dust and clouds can make the red color more intense.
