Auroras from Google AI

An aurora is a natural, shimmering light display in Earth’s upper atmosphere. They occur when charged particles from the Sun (solar wind or coronal mass ejections) interact with Earth’s magnetic field and collide with atmospheric gases like oxygen and nitrogen.

Colors and Altitudes

The colors depend on which gas atoms are hit and at what altitude the collisions take place:

• Green: Produced by oxygen atoms at roughly 100 to 150 km (60–90 miles) altitude; this is the most common color.

• Red: Produced by high-altitude oxygen at higher elevations (above 300 km or 180 miles) through a slower energy release.

• Blue and Purple / Violet: Produced by molecular nitrogen at lower altitudes (90 to 200 km).