Why is the sky blue?

 

The sky appears blue due to a process called Rayleigh scattering. When sunlight enters Earth's atmosphere, it contains a mix of all colors of light, which together appear white. Each color of light has a different wavelength, and blue light has a shorter wavelength than most other colors.

The shorter wavelengths of blue light are scattered in all directions by the tiny molecules of air and other particles in the atmosphere. This scattering causes the blue light to spread out across the sky and become more visible to our eyes from any direction we look.

Other colors, like red and yellow, have longer wavelengths and aren't scattered as much, which is why they don't dominate the sky's color during the day. However, during sunrise and sunset, the light has to pass through a thicker layer of the atmosphere, scattering the blue light out of our line of sight and allowing the reds and oranges to become more prominent.

So, the reason we see a blue sky is because the blue wavelengths of sunlight are scattered in all directions by the molecules and particles in the atmosphere, making it the most visible color to us during the day.