|
The color of an aurora depends on the identity of the atoms or molecules struck by the charged particles.
The brilliant all-red auroras are due to high-altitude oxygen atoms that have been bombarded by high-energy electrons. Oxygen atoms at lower altitudes produce brilliant yellow-green
auroral lights. Ionized nitrogen atoms produce blue auroral lights, and neutral nitrogen molecules produce red. Purplish-red auroral borders occur when the colors from nitrogen mix.
|