Green Sky of Yellowknife

The northern lights dominate the sky above Yellowknife in northern Canada. Aurora, which is mostly seen from polar latitudes, is also known as the northern or southern lights. It is produced by the collision of charged particles from Earth’s magnetosphere, mostly electrons but also protons and heavier particles, with atoms and molecules of Earth’s atmosphere (at altitudes above 80 km). The particles originate from the Sun and reach the Earth in the stream of solar wind.