GREENVLLE, N.C. (WNCT) — One common question asked about the atmosphere is how in the world does our sky change colors?
During the day we see a beautiful shade of blue, and when the sun sets, beautiful shades of pink, orange, red and sometimes purple gleam through the sky.
Sunlight is made of all colors. For example, the visible spectrum is used by scientists to show different wavelengths of light. Each color has a different wavelength. Blue has the shortest wavelength and red has the longest.
Each beam of light travels to the surface containing all colors, but some of them are filtered out by particles and gases along the way. During the day, the sun is directly above the earth at a 90-degree angle. Light travels a shorter distance to reach the human eye. Because blue has the shortest wavelength, it is the first color to be filtered out by particles in the sky. And that’s why we see a blue sky during the day.
During sunset hours, light has to travel a farther distance because it is not directly above Earth’s surface. Because the light has to travel a farther distance, more particles get in the way, filtering out even more color.
Yellow, orange, and red have the longest wavelengths, so they can travel at further distances. Purple, blue, and green are scattered out along the way. That’s why we see those deep colors of reds, pinks and oranges as the sun sets.
Step outside any evening to see this process play out in action.