The interaction between light from the Sun, charged particles, and molecules in the atmosphere can create a variety of glowing phenomena. The best known are the
In an image snapped by astronaut
This weak luminescence in the upper atmosphere is caused by the interaction between light and the molecules or atoms. Sunlight energizes molecules over the day, slitting them apart, or exciting electrons from their atoms. The energy is then lost in the following hours, due to collisions with other molecules. That emission of energy happens at a specific color, creating the characteristics of
As long as there are molecules and atoms to excite, airglow can form. While most of it comes from a fairly narrow region, between 50 and 300 kilometers (31 to 180 miles), NASA reports that it can extend over twice as far. And while it is a pretty spectacle, it can also be very useful, providing insight in the motion and distribution of the extremely rarefied layers in the