Why Is The Sky Blue? (Encore)

Sunrise Colors

The sky's color during sunrise and sunset is a fascinating phenomenon. Gary Arndt explains that the sky can appear red, yellow, or orange due to Rayleigh scattering. This occurs because the light has to travel through more atmosphere at these times, scattering shorter blue wavelengths and leaving longer red and yellow wavelengths to reach our eyes 1.

The amount of atmosphere between you and space is shortest when you go straight up, but when you look to the horizon, there's much more atmosphere that the light has to go through.

--- Gary Arndt

Interestingly, the sky can also turn green before a tornado due to water molecules scattering the remaining green wavelengths 1.

   

Storm Effects

Weather conditions like storms can significantly alter the sky's color. Gary Arndt mentions that storm clouds can cause the sky to turn green, especially before sunset when tornadoes are most common 1. This eerie phenomenon occurs because the blue light is scattered away, and water molecules scatter the remaining green light.

The green part of the spectrum which hasn't been scattered by the atmosphere, can now be scattered by water molecules.

--- Gary Arndt

Such changes in sky color are rare but notable, adding to the complexity of atmospheric interactions 1.

   

Planetary Skies

The color of the sky can vary dramatically on different planets due to their unique atmospheric compositions. Gary Arndt explains that Mars, for example, has a butterscotch-colored sky due to its iron-rich dust absorbing blue light 1. However, rovers have detected a bluish halo around the sun during specific conditions.

The martian atmosphere is very different than the earth's. For starters, the pressure is less than 1% of ours so there just isn't much of it.

--- Gary Arndt

Different atmospheres and light profiles from other stars could result in various sky colors on other planets, highlighting the diversity of planetary environments 1.