Buzz
Light consists of waves of varying lengths called wavelengths. The shorter wavelengths appear blue. Our atmosphere acts like a protective shield made up of gases and particles that surround the Earth. When sunlight strikes this atmosphere, the light waves scatter in all directions, with the shorter blue wavelengths scattering the most.
We perceive different wavelengths as distinct colors. Sunlight appears white, but in reality, it contains all the colors of the rainbow. Longer, larger waves appear red to us, while shorter waves look blue. These colors are visible only when light is bent (like through a prism), reflected (like off a mirror), absorbed (like by red sneakers), or scattered (like in the atmosphere). Since shorter wavelengths are more easily scattered by the atmosphere, the sky predominantly looks blue.
The sky's blue appearance is due to the scattering of shorter waves in the atmosphere, which primarily affect the blue wavelengths.
Our eyes are capable of perceiving only a small portion of the colors present in the vast universe, with sky blue being one of them! The colors we can see are known as visible light. However, much of the light in the universe remains invisible to us, as it radiates at wavelengths beyond our sight. To detect these, we need special tools. These invisible wavelengths include gamma rays, X-rays, ultraviolet radiation, infrared radiation, microwaves, and radiowaves.
For additional enjoyable reading, check out NASA's response to this classic question. It includes informative illustrations.
