What is Rayleigh Scattering?

Have you ever wondered: Why is the sky blue?
You may have heard many myths in response, like “the sky is a reflection of the ocean”, but the real answer to this question is Rayleigh scattering.

What is Rayleigh scattering?

Discovered by Lord Rayleigh in the 1800s, Rayleigh scattering is the scattering of light particles off of the molecules in the atmosphere.

In our atmosphere, there are many gases such as Nitrogen, Oxygen, and Hydrogen. Mixed in with these elements are particles, including dust, pollen, and pollution.

White light from the sun is shining in the sky, and you may know that this white light is actually composed of different colors, which can be seen through a rainbow. The rainbow displays all the combinations of red, green, and blue that your retina is able to generate, and is a full encapsulation of all the colors visible to the average human eye.

These colors have different wavelengths, with red having the least wavelength and violet with the highest wavelength. Some of the particles I mentioned earlier, are about the same size as the wavelength of blue light. This means that the blue light will reflect and scatter off of those particles, giving us the blue hue we see in the sky.

Picture Source: ScienceSense