Aurora on Jupiter, combined ultraviolet and Hubble Space Telescope (HST) image. This image combines an optical image (spring 2014) taken by the HST, with ultraviolet observations in 2016 of its aurorae (blue). Aurorae are produced by the interaction of the solar wind with a planet's atmosphere. Charged particles collide with gases in the upper atmosphere, causing them to emit light. On Jupiter, as on Earth, they occur in polar regions. This is because the magnetic field of the planet channels the charged particles to these regions. Image published in June 2016.