Look up on a clear sunny day and you will see a blue ... sky. This glow, called airglow, is produced by atoms and molecules in the atmosphere. In visible light, oxygen produces green and red ...

The expansion of space stretches the wavelengths of the light that is traveling through it. Since red light has longer wavelengths than blue light ... the Sloan Digital Sky Survey and found ...

An avid stargazer may notice that apart from the gleaming white stars that sprinkle the night sky, there are red ... but because it also emits a lot of light in colors such as red and blue, the Sun is ...