The dancing light of the auroras on Saturn behaves differently from how scientists had thought possible.
By choreographing the instruments aboard the Earth-orbiting Hubble Space Telescope and the Cassini spacecraft, while it was enroute to Saturn, to look at Saturn’s southern polar region, scientists found in 2005 that the planet’s auroras, long thought of as a cross between those of Earth and Jupiter, are fundamentally unlike those observed on either of the other two planets. The ruby-colored lights that occasionally paint the sky over Saturn may, in fact, be a phenomenon unique within our solar system.
Hubble snapped ultraviolet pictures of Saturn’s auroras over several weeks and Cassini recorded radio emissions from the same regions while measuring the solar wind, a stream of charged particles that trigger auroras. Those sets of measurements were combined to yield the a glimpse of Saturn’s auroras.
The observations showed that Saturn’s auroras differ in character from day to day, as they do on Earth, moving around on some days and remaining stationary on others. But compared with Earth, where auroras last only about 10 minutes, Saturn’s auroras can last for days.