Mean distance from Sun: 778,600,000 km
Orbital Period: 11.8618 years
Rotational Period: 9 hours, 50 minutes
Composition: hydrogen, helium, methane
A failed star comprised mostly of the same elements as the Sun. It is considered a failed star because it is not massive enough to initiate and sustain the nuclear fusion of hydrogen into helium, the energy process that powers the Sun and all other stars. The aurorae observed at the poles are thought to be caused by the interaction of sulfur and oxygen ions in the outer regions of Jupiter’s magnetic field with particles from the Sun’s so-called solar wind. The ions originate from volcanoes on Jupiter’s moon Io and have been pulled into Jupiter’s magnetosphere. It is unknown why the northern aurora pulsates at a rate of roughly once every forty-five minutes.
Observed high-energy auroral activity on Jupiter occurs at latitudes too high to be caused by ionized particles ejected from the surface of Io and trapped in Jupiter’s magnetosphere. Jupiter’s aurorae are powered by its direct electrical connection to the Sun and at least three of its closest moons: Io, Ganymede and Europa. This connection accelerates trapped ions from the Sun causing them to bounce between Jupiter’s poles, oscillating at the pulsation rate measured and emitting radiation in the form of X-rays and radio waves.