SUNSETS

Have you ever driven home from work in the evening hours and noticed the sunset? Did you ever wonder what causes such brilliant colors in the evening and when the sun rises in the morning? Beautiful shades of orange, pink, purple, and red can be best seen in the fall and winter seasons at mid-latitudes. In this post, we’ll look at images of various sunrises and sunsets and explain why they show such beautiful colors!

The best time to see amazing sunrises and sunsets is typically in the fall and winter months in the mid-latitudes. The key ingredients to see such beautiful colors is a lack of pollution, a few high clouds, and the sun angle. Have you ever wondered why the sky is blue? The sky appears blue due to a scattering of violet and blue light by air particles. Visible light is part of the electromagnetic spectrum that we can see. The blue colors in the sky is due to a process called Rayleigh scattering. Blue and violet colors have shorter wavelengths (0.47 nanometers [nm]), and are typically scattered more due to the gases in our atmosphere. Longer wavelengths such as red, orange, and yellow (around 0.55 to 0.65 nm) simply pass straight through our air, which explains why our sky cannot be red. Pollution in the atmosphere can soften the colors in the sky and reduce the light given. In this case, pollution can negatively effect the colors seen.

In the morning and evening hours, sunlight has to take a longer path through the atmosphere due to the low angle of the sun. For this reason, this explains why fall and winter are ideal seasons to see such beautiful colors because the angle of the sun is lower. High clouds such as cirrus and altocumulus can catch the light that did not suffer attenuation and/or color loss by passing through our atmosphere. In other words, when the sun rises or sets, sunlight has to pass through more air than in the daytime. When sunlight travels through more atmosphere, it provides more molecules to scatter the violet and blue light away from our eyes. If the path is log enough, we no longer see blue skies, but we’ll begin to see hues of red, orange, pink, yellow, and purple. Clouds can help scatter and reflect light, which can influence everything outside to have a red hue like color. For instance, in the image below, the entire landscape took on the fading colors of the setting sun’s red and orange glow, which allows very little blue light from being scattered from the upper levels of our atmosphere