The beautiful colors of sunrise and sunset occur because sunlight must travel through more atmosphere to reach our eyes when the sun is near the horizon. This phenomenon is called atmospheric scattering. During these times:
- Sunlight travels through up to 40 times more atmosphere than at midday
- Blue light gets scattered away more completely
- Red and orange wavelengths pass through more directly
Additionally, dust, pollution, and water vapor in the atmosphere can enhance these colors by providing more particles for light to interact with. This is why particularly stunning sunsets often occur after volcanic eruptions or in areas with moderate humidity.