Video narration
On a clear day, the sky looks blue—but it’s not because the air is colored. Sunlight is actually a mix of all colors, which together look white. As that light enters Earth’s atmosphere, it runs into tiny air molecules. They scatter the light, meaning they bounce it in many directions. Here’s the key: shorter-wavelength light gets scattered much more than longer-wavelength light. Blue light has a shorter wavelength than red, so it spreads out across the whole sky. When you look up, you’re seeing that scattered blue light coming from every direction. Meanwhile, more of the reds and yellows pass through the air more directly, which is why the Sun itself can look warmer in color—especially near sunrise and sunset.