Aurora colors: What causes them and why do they vary? - Space
: Because nitrogen is harder to "excite" than oxygen, purple lights generally only appear during strong geomagnetic storms when solar particles have enough energy to penetrate deeper into the atmosphere. 1024x768 purple northern lights wallpaper | Nor...
: Unlike the common green aurora caused by oxygen, purple and blue hues are produced by ionized nitrogen . Aurora colors: What causes them and why do they vary
Purple northern lights, while a favorite for high-definition wallpapers, are a rare and scientific marvel caused by the interaction of solar particles with at specific altitudes. These colors typically appear during periods of intense solar activity and are often visible at the lower edges of an auroral display, usually at altitudes of 60 miles (100 km) or less . The Science Behind the Purple Glow Purple northern lights, while a favorite for high-definition
The "magic" of a purple aurora is actually a chemical reaction in our atmosphere:
: These colors form in the denser parts of the upper atmosphere, below 60 miles, where nitrogen is more abundant than oxygen.