Blue Skies


The sky is blue... that should not shock anyone reading this. But, have you ever stopped and wondered why the sky is blue? I have and I just thought it was blue because that was the color. Just like everything else in the world, there is some reason as to why the sky is blue. 

The first step in beginning to understand why the sky is blue is to learn about color. The human eye sees color when light leaves an object and the light bounces off of particles in the air. The sun looks yellow and the light from the sun looks white to us. The sun actually gives off light that is colors of the rainbow. But, we see the sun giving off white light because when all the colors of the rainbow are mixed, they form white.

The sun shines it's light through the sky. The sky has particulates floating around that the human eye cannot see. The color blue has wavelengths that cannot pass through the particulates and therefore bounce off the particulates.  When the sun's light is shined throughout the air, all the colors of the rainbow are scattered, although we can not see them. As the colors are traveling through the air, most of them shine right through the particles, except the color blue. The color blue's wavelength makes the light of blue from the sun bounce off the particles. The blue light bounces from particulate to particulate until it reaches our eyes. The other colors of the rainbow just pass right through the particulates and that is why we do not see all the colors in the sky.

When the sun is rising or setting it scatters the colors a different way. I read an article and the way Steven Ackerman, professor of meteorology at UW-Madison, explains why the colors in the sky are different at sunsets and sunsets is the shortest and simplest way I found to understand it.

We can now understand that the sky is blue because of the particles in the sky and they way that the suns light reflects on the particles. The way the sunlight reflects off the particles, is how our eye forms the color we see. 

Now when you look up to the sky, you should have a better understanding of why the sky is blue and why it looks different at sunrise and sunset. I know I love to watch the sun set, especially at the arboretum right here in Happy Valley!

 Will you look at the sky differently now?


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I was very surprised when I read your post because my whole life up until now I always thought that the sky was blue because it was a reflection of the ocean ! I don't remember who told me that but I remember someone did and I always just thought that was the main reason... This post reminds me of my Astro class when we learned about light and particles and wavelengths and now everything makes sense . Here is a link I found that has some of the coolest sky pictures enjoy!:)

This is a very interesting concept to bring up. The reasoning behind the coloring of the sky does make sense though because of the reflected wave length colors. Its amazing how the colors we do see in nature are because of the same concept. Although I did not know the sun was apart of the process and I also didn't know the sun emitted all of the colors of the spectrum. Can you imagine if the sun was a different color or size, such as a dwarf or a giant red? Then what color would the sky be?

I feel sad to admit this but I never once thought about why the sky was blue, until I read your post. So I definitely became interested in it pretty fast! Like Laura said I never would have thought the sun would produce beautiful colors like that and we only see white. I was thinking how crazy it is that water (rain drops) can break the sun colors into what we call rainbows and actually see the true light from the sun. I wonder what it is about raindrops that can break the white light into the sun's actual light? For now on I will look at rainbows differently!

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