Why is the sky blue?

Light is something interesting. It travels through the space, from our sun to this planet, at an average of eight minutes, twenty seconds; and, here, it goes through the atmosphere and helps us see the difference between day and night.

Looking up, we see a fantastic blue colour. Why is the sky blue? —we have all wondered. Well, the answer is not that difficult.

When the light touches something, this 'something' reflects all its colours except the colour the thing is composed of. So, if the light happens to touch something red, like an apple, the apple reflects all colours but the red, because it is somehow trapped by its surface. We see the colours that are trapped within the objects.

If we see that the sky is blue, it is because it is absorbing the colour of the nitrogen. More than seventy percent of the atmosphere is composed of this bluish gas.

Knowledge + Why?