LOUISVILLE, Ky. — Have you ever wondered how we get such beautiful colors in the sky during our sunrises and sunsets?
They're pretty spectacular here in Kentucky and Indiana. There are a few reasons why our sunsets are so pretty.
One is the presence of dust particles in the air, but the main reason we see so many colors is because of "scattering." Scattering is the scientific term to describe the reflection or redirection of light.
One type of this is called "Rayleigh Scattering," the term is used to explain how the scattering of light varies with wavelength of light. Air molecules are very tiny - smaller than some of our smallest wavelengths of light and that makes them great at scattering.
Before the scattering comes into play it is important to note, light from the sun is white, but our spectrum of light shows us that light is reflected in different colors and wavelengths.
If we looked at the sun from space, it would appear white. As the sun's light rays enter Earth's atmosphere, they are scattered. Red wavelengths are longer than blue or purple.
In the middle of the day, when the sun is overhead, the light from the sun has its shortest path through the atmosphere to reach us. Blue waves are shorter and scatter - that helps make the sky look blue.
The sun looks yellow because longer red, yellow and green wavelengths make through the atmosphere easier. The sun can also appear white when light rays encounter very little interference.
Now at sunrise and sunset, the sun is at a much lower angle to earth. This means light has to take a longer path to reach us.
Shorter blue wavelengths have a much lower chance of making it towards us while the longer red and orange wavelengths can scatter a bit, but still stay long enough to make it through the atmosphere to our eyes.
Now what role do clouds play?
Clouds catch the last red-orange rays of the setting sun and the first light of the dawn like a theater screen, and reflect this light to the ground.
High clouds like cirrus or altocumulus clouds tend reflect light waves the best because they are high in the atmosphere and have the best chance to get rays of light before they're reflected too much.
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