BellaOnline Forums Education Astronomy Why the Sky Looks Blue

A sunny day with a beautiful blue sky may prompt a child to wonder why the sky is blue. It's a good question. After all, the Sun isn't blue, and even if the sky above us looks blue, the air around us doesn't. The answer has to do with sunlight, Earth's atmosphere, and our eyes.

Why the Sky Looks Blue

Here's a diagram with a nice summary of why the sky is blue and not some other color. (It doesn't deal with clouds and sunsets.)

Thank you for breaking this down so that those of us who love the sky but get confused by the hard science can understand!

Merope is one of the Pleiades (the Seven Sisters) and here is a Merope and her reflection nebula. Tiny grains of carbon in the nebula reflect the light, scattering the blue light more efficiently than the redder light. This is an example of Rayleigh scattering - a phenomenon that also makes Earth's sky appear blue.

(Image Credit & Copyright: Leonardo Orazi)

Attention, teachers, educators and people who are curious! Here is a simple experiment showing hwy the sky may look blue during much of the day, but red at sunrise and sunset. See Why the Sky Is Blue and the Sunset Is Red.