Explosions in Jupiter's Shimmering Aurora Linked to Its Moon, Io

On Earth, bursts of particles from the sun spark shimmering auroras, like the Northern Lights. On Jupiter, though, there's an aurora that glows continually. Now, new observations reveal that this display sometimes flares up because of a process that has absolutely nothing to do with the sun.

Those who look through telescopes to see the gas giant, Jupiter, have long known that the planet has ever-present polar auroras. These auroras are many thousands of times brighter and bigger than those on Earth, and are powered by both electrically charged particles from the sun and a separate interaction between Jupiter's magnetic field and one of its moons, Io. However, there are also auroroal explosions on Jupiter, which are periods of dazzling brightening. These explosions are similar to the auroral storms on Earth.

In the aurora-making interaction between Jupiter and Io, volcanoes on the small moon blast clouds of electrically charged atoms and electrons into a region surrounding Jupiter that's permeated by the planet's magnetic field. The magnetic field drags the material from Io around with it, causing strong electric fields at Jupiter's poles. This produces auroras that shine in almost all parts of the electromagnetic spectrum.

New observations, though, reveal that the violent explosions of Jupiter's aurora likely are kicked off by the planet-moon interaction and not by solar activity. The researchers witnessed explosions of the planet's aurora despite a calm solar wind, which suggested it's the moon driving the interactions rather than the sun. That said, researchers are still unsure exactly what occurs in the Jovian magnetosphere to cause the temporary brightening of auroral explosions.

The findings are published in the journal Geophysical Research Letters.

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