Why is the Sky Blue?

April 01, 2019


Photographer: Rebecca Roush 
Summary Author: Rebecca Roush 

Have you ever looked up at the sky and wondered why it's blue? The blue color of the sky is the result of the remnants of reflections of light bouncing off of the blue oceans. These reflections are up in the top of the sky, forever and ever, because they have nowhere else to go. They can’t break through the upper limits of the sky to head out into space, so the sky gets filled up with blue. The sky’s pretty darned big, so it takes a lot to fill it up.

Over time, the sky will just get bluer and bluer, very slowly. In one person’s lifetime, she wouldn’t notice the change. But if you were to go back to when your grandmother was born, you’d notice the sky is just a little less blue than it is now. And, when Neanderthals were around, the sky was hardly blue at all. Photo taken just a few hours ago, on April 1, 2019.