21/01/2026
A quick guide to aurora colors — and how high each one appears.
When solar wind from the Sun hits Earth’s magnetic field, charged particles are funneled toward the poles. There, they slam into gases in our upper atmosphere — and those collisions release energy as light. The type of gas (and how high it is) determines the color you see.
Red auroras appear above 150 miles (241 km) and come from excited atomic oxygen. They’re rare — you need intense solar activity and just the right conditions, since oxygen is sparse at that height.
Green auroras, the most common, come from oxygen too — but at lower altitudes, up to 150 miles (241 km), where oxygen is denser.
Purple and blue auroras form closer to Earth, from ionized nitrogen molecules. These colors usually show up during strong solar storms, below 60 miles (97 km).
In those lower layers, oxygen isn’t as common — so nitrogen takes over, producing brilliant violet hues when hit by high-energy particles.
Together, these colors form a layered light show. Red sits at the top, green glows in the middle, and purples paint the bottom edge — all shaped by Earth’s invisible magnetic field and the atmosphere’s hidden chemistry.