Question: Why is the sky blue

Stephen Rhatigan answered on 6 Nov 2017:

The sunlight that we can see is made of waves of different colours. When all these waves travel together they look white but they can be split into their different colours (think of a rainbow).

When the sunlight reaches earth the blue waves bounce off particles in our atmosphere and are scattered in every direction.

This doesn’t happen as much for the other colours of light and so we see the sky as blue.

From the moon, the sun looks like a bright white fireball against a black background. This is because the moon has little or no atmosphere to scatter the light.