The Ghost of Yellowknife

Dancing lights of aurora is captured in this all-sky view from Yellowknife in northern Canada. Aurora 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. When a bright auroral patch leads to a point directly above the observer, the aurora may appear as a “corona” of diverging rays, an effect of perspective. © Yuichi Takasaka