APOD: 2022 March 13 - Colorful Airglow Bands Surround Milky Way

Good afternoon, Rallypoint, and welcome to the March 13th Astronomy Picture of the Day (APOD): "Colorful Airglow Bands Surround Milky Way." What is airglow? It is the light of electronically and/or vibration-rotationally excited atoms and molecules in the layer of our atmosphere called the thermosphere. Temperatures here are highly dependent on solar activity, and can rise to 2,000 °C (3,630 °F) or more. These extremes produce airglow: Oxygen molecules produce a blue or red light depending on their elevation. Oxygen molecules produce a green light, sodium molecules yellow, and hydroxy free radicals burgandy.

This image first appeared in May 2018, and makes a repeat APOD appearance today. Airglow is readily visible from space, but is too transitory to be visible from Earth. The colors in this image have been digitally enhanced to better represent the different elements in the thermosphere. As you can see, airglow moves and changes much like the ripples created by throwing a stone into a pool of water.