Every since I was a kid, I was told and could easily see that the sky was blue. I never questioned it, it saw it was blue and I could see that it was true. As I was thinking of topics to write about for this blog period, I was really blanking and thought about the most basic question I could think of: why is the sky blue? When I see pictures of other planets, it appears as though you can see all the stars and other planets in the galaxy, so why is Earth so different. The atmosphere that we have has some effect as to why the sky looks different on Earth than it does on Mars, but so does the visible light that reflects off of the sun.
Light energy travels in waves, similar to the ocean. Some light, such as blue light, travels in short choppy waves, while other colors, such as, red travel in much longer waves. Naturally, all light travel in a straight line, until hit by an outside force such as a mirror, prism, or molecules in the air. When light hits the Earth’s atmosphere, the gases and molecules in the air scatter the light in all different directions making it’s wave very short and choppy. This is why the sky is blue. For a diagram, click here!
If you have ever noticed on a plane, the sky seems to appear a darker blue the higher up. The blue light looks much lighter or even white the closer you are to earth. This is due to the scattering and rescattering of the blue light from the top of the atmosphere to the ground. Think of it as a feather that is dropping from the top of a building. The wind (or the molecules in the atmosphere) make the feather move in all different directions and pieces of the feather fall off. The farther down the feather goes, the more it has moved and more pieces have come off. By the time the feather reaches the ground, not much of it is left. This is how blue light works. It is it’s strongest at the top and after being scattered so many times does not have much left to it at the end. This is why the sky has a blue ombre effect.