Finland · Northern lights
On the night into Sunday 11 October, the geomagnetic index Kp reached 7, according to NOAA SWPC's measurements. The solar storm pushed the northern lights far north – including over Finland.
| City | Chance |
|---|---|
| Helsinki | Good |
| Ivalo | Good |
| Rovaniemi | Good |
| Oulu | Good |
| Tampere | Good |
What is happening on the Sun?
Auroras form when electrically charged particles from the Sun hit Earth's magnetic field and are channelled down into the atmosphere around the poles. At 100–300 kilometres up, they collide with oxygen and nitrogen, which light up – oxygen in green and red, nitrogen in blue and violet.
That corresponds to a strong geomagnetic storm, G3 on NOAA's scale from 1 to 5.
The Kp index runs from 0 to 9 and shows how disturbed Earth's magnetic field is. At Kp 3, the northern lights are usually seen only in northern Norway, Lapland and Iceland. From Kp 5 they can reach Denmark, Scotland and northern Germany, and at Kp 8–9 they have been seen as far south as southern Europe.
The Sun is still very active after the peak of its 11-year cycle. Skycastor will write as soon as the next storm is on its way.