On This Day in Science History - June 30

June 30^th marks the passing of the man who answered the question: "Why is the sky blue?"

John William Strutt, or Lord Rayleigh determined that the gas molecules in the air scatter the sunlight as it passes through the atmosphere. This scattering effect is called Rayleigh scattering in his honor. The light we see depends on the angle between the light source and you. When the sun is low on the horizon at sunrise or sunset, the longer wavelengths of light are scattered more and you see reds and oranges. As the sun rises higher into the sky, the wavelength that is scattered is shorter and we see blue.

Find out more about Lord Rayleigh and what else occurred on this day in science history.