Aurora borealis (northern lights) over a snow-covered landscape during a geomagnetic storm. A geomagnetic storm is a temporary disturbance of the Earth's magnetosphere caused by a solar wind shock wave and/or cloud of magnetic field which interacts with the Earth's magnetic field. Auroral displays at much lower latitudes than normal are commonly associated with such an event. The aurora borealis is a coloured light display that is visible in the night sky at high latitudes. It occurs when charged and energetic particles from the Sun (the solar wind) are drawn by Earth's magnetic field to the polar regions. Hundreds of kilometres up, they collide with gas molecules and atoms, causing them to emit light. Photographed in Meloy, Norway, in