Cassini captures auroral display at Saturn's south pole

Beautiful images of Saturn’s spectacular auroral light-show have recently been created using optical and infra-red data collected by NASA’s Cassini spacecraft over the last few years. The composite false-colour image below shows the aurora sitting over a 1000km above the cloud-tops around Saturn’s south pole region.

Comparison of the Gliese 581 system
False-colour image of aurora at Saturn's south pole - © NASA

Saturn’s aurora is created in the same way as the northern and southern lights are here on Earth. Solar wind particles (or plasma) are channelled towards the planet’s magnetic poles, where interaction with particles in the atmosphere results in the emission of light in various colours. Saturn’s auroras differ slightly, in that they can also be affected by moons passing through the magnetic field (or magnetosphere) generated by the planet's churning core, which acts to deflect the majority of the solar wind.

The following video, compiled from over twenty hours (around two Saturnian days) of observations, shows a clear pattern in the daily routine of the aurora, suggesting that it is sensitive to local conditions, such as Saturn’s orientation relative to the Sun and the direction of the magnetic field.