Wind of the Sun

Dancing lights of aurora appear in the sky of Great Slave Lake, Yellowknife, northern Canada. Notable in the background sky is the V-shaped Hyades star cluster (face of the Bull or Taurus) at lower left corner and Pleiades star cluster above it. 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. © Yuichi Takasaka