Unlike Earth's aurorae, which are transient and only occur at times of heightened solar activity, Jupiter's aurorae are permanent, though their intensity varies from day to day. They consist of three main components: the main ovals, which are bright, narrow (< 1000 km in width) circular features located at approximately 16° from the magnetic poles;[20] the satellite auroral spots, which correspond to the footprints of the magnetic field lines connecting their ionospheres with the ionosphere of Jupiter, and transient polar emissions situated within the main ovals.[20][21] The auroral emissions were detected in almost all parts of the electromagnetic spectrum from radio waves to X-rays (up to 3 keV).