The Science Behind A Perfect Sunset

Be honest, you probably have more pictures of sunsets on your phone than you do of your family. The red, purple and orange hues are so beautiful and captivating that us weather fans just can’t help it! Have you ever wondered what atmospheric factors impact the way sunsets look? If you answered yes, then 1) you’re a true weather geek and 2) you’re in luck.

The main ingredient for a perfect sunset is a sky full of aerosols. Aerosols are particles created by natural events, such as pollution and wildfires. If you’re in the southeast region where the wildfires are happening, you may want to poke your head outside in the evening to see a brightly-colored sunset!

The aerosols from wildfire and pollution are 100 nanometers in size. This means they’re ten times bigger than the smoke particles from tobacco. Aerosols deflect and scatter the sun’s light all throughout the day, but they scatter blue and violet wavelengths nine times more efficiently than any other color. The average length of blue and violet wavelengths are between 350 and 450 nanometers, while the red and orange wavelengths measure around 700 nanometers. This means the warm color wavelengths are able to penetrate the aerosol layer more easily. Are memories from your high school physics class flooding back into your memory yet?

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When the sun sets, it travels horizontally across the atmosphere. However, the atmosphere it travels across in the evening is twice as thick as the atmosphere it travels across during the day. The aerosols scatter blue and violet wavelengths across the thick atmosphere full of aerosols before reaching our eyes, so the warm color wavelengths are left behind for us to see and enjoy.

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Sunsets across the world all vary by aerosol levels and topography. For example, Los Angeles has sunsets that are more red than Chicago sunsets because the aerosols can’t dissolve as easily due to the physical features of the land. LA’s average level of ground ozone is 50% higher of comparable cities like Chicago, which creates smog but also great sunsets.

Want to find out more about how vivid sunsets are formed? Watch the video below! Also, if you have amazing sunset photos, submit them to our Community Gallery.


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