AURORA
A storm you can see.
It starts as wind.
The Sun sheds a thin stream of charged particles. Earth's magnetic field holds it off, tens of thousands of kilometres out. Turn the wind's own field south and the two join. Energy gets in.
- Pressure
- Boundary, sunward
- The two fields
It lands in a ring.
Stored energy falls along field lines toward both poles and arrives in two ovals. They stay fixed toward the Sun while Earth turns beneath them. The dashed line is you.
- Activity, Kp scale
- Oval edge at midnight
Colour is altitude.
Each colour is one gas at one height. Oxygen near 100 km glows green within a second. Far higher, thin oxygen glows red, slowly. Ionised nitrogen adds violet at the edges of strong storms.
Your sky.
An illustration built from published relationships. Not a forecast, and not a photograph.