What Makes That Fire in the Sky: The Science Behind Sunsets

In the evening hours, as the sun descends into twilight, we are greeted by a wave of colors known as a sunset. For a brief moment, we are reminded to pause our chaotic minds and enjoy the splendor above us. If you live in Arizona, you are all too familiar with this daily vibrant experience.

What’s behind the colorful wonder? Sunsets are as scientifically intriguing as they are beautiful. In fact, the reason Arizona has some of the most magnificent sunsets in the world is due to a combination of air quality, time of year, and chance. However, before we uncover the truth about Mother Nature’s scarlet display, we must first understand the reason why the sky is blue in the daytime.

Why is the Sky Blue?

The sun emits energy onto the Earth in the form of white light. As you may remember from science class, white light is actually a spectrum of colors ranging from ultraviolet to infrared. The colors vary from short to long wavelengths. For example, blue and violet light have shorter wavelengths compared to red and orange.

When sunlight enters our atmosphere, it is no longer a direct beam of white light. Instead, the blues and purples with shorter wavelengths start bouncing off of nitrogen, oxygen, and various other air molecules in the atmospher