Why is the sky blue, and the sun set orange?
kumorifox is only half-correct. The rest of the answers are wrong. During the day, the sky is blue because air particles scatter the blue part of the sun’s spectrum more than red. Blue light is short wavelength and “bounces off” the air and dust particles. Red light is long wavelength and passes straight through the atmosphere. When the sun is low on the horizon, the sunlight has to go through more of the atmosphere and dust, so practically all of it is scattered, apart from the more direct red and orange light from the sun. That’s why the sunset appears orange.
