How solar storms create the Northern Lights
The solar storms that create the Northern Lights that have been seen this week are being studied by scientists in the Arctic to see why they disrupt satellite navigation systems.
Flares from the Sun interact with the upper atmosphere and can distort the signals from global positioning satellites, affecting measurements by tens of metres.
The research project is under way at a remote observatory in the Norwegian archipelago of Svalbard in the High Arctic.
Professor Dag Lorentzen explained to the BBC's science editor David Shukman how solar storms affected the Earth's magnetic field to create the aurora borealis.