Space Weather 101
🌌 Aurora
View live Aurora data →What is Aurora?
The aurora (borealis in the north, australis in the south) is a natural light display caused by charged particles from the solar wind colliding with gases in Earth's upper atmosphere. Earth's magnetic field channels these particles toward the polar regions, where they collide with oxygen and nitrogen atoms, exciting them and causing them to emit light as they return to their normal state.
Why it matters
Aurora is the most visible, tangible sign of space weather activity — the same processes that can disrupt satellites and power grids also produce this striking natural phenomenon, making it a genuine (if imprecise) visual indicator of geomagnetic conditions.
Typical values
The aurora oval typically sits around 65-70° magnetic latitude during quiet conditions, expanding toward the equator as geomagnetic activity (Kp) increases — reaching mid-latitudes during a G3 storm and, rarely, low latitudes during G4-G5 extreme events.
How scientists measure it
Beyond direct visual and photographic observation, scientists track aurora activity via the OVATION model (which estimates aurora probability and location from real-time solar wind data), ground-based all-sky cameras, and satellite imagery from space.
Why it affects Earth
Aurora itself is a harmless visual effect, but it's a direct sign that Earth's upper atmosphere and magnetic field are actively absorbing energy from space weather — the same underlying conditions can simultaneously cause radio disruption, GPS errors, and (in strong events) power grid stress.
FAQ
What causes the different aurora colors?
Color depends on which atmospheric gas is excited and at what altitude. Oxygen produces green (most common, lower altitude) and red (higher altitude, seen in stronger storms); nitrogen contributes blue and purple hues, often at the aurora's lower edge.
Can I see aurora without a strong Kp?
Yes, from high-latitude locations like northern Scandinavia, Iceland, or Alaska, aurora is visible on many clear nights even at low Kp — because those locations already sit under the aurora oval most of the time.