Saturn's Auroras Caused By Its Collapsing Magnetotail

Posted on May 19, 2014

University of Leicester researchers says Saturn's auroras are caused by its collapsing magnetic tail. The researchers captured images of Saturn's northern UV auroras as the planet's magnetic field is battered by charged particles from the Sun. The ultraviolet images were taken by Hubble's super-sensitive Advanced Camera for Surveys. The team caught Saturn during a dynamic light show. Some of the bursts of light seen shooting around Saturn's polar regions traveled at over three times faster than the speed of the gas giant's rotation.

Just like comets, planets, like Saturn and Earth, have a "tail" called the magnetotail. The magnetotail is made of electrified gas from the Sun which flows out in the planet's wake. When a strong burst of particles from the Sun hits Saturn, it can cause the magnetotail to collapse, which results in auroral displays. A similar process causes auroral displays here on Earth.

Dr Jonathan Nichols, of the University of Leicester's Department of Physics and Astronomy, who led the Hubble observations, says in a statement, "These images are spectacular and dynamic, because the auroras are jumping around so quickly. The particular pattern of auroras that we saw relates to the collapsing of the magnetotail. We have always suspected this was what also happens on Saturn. This evidence really strengthens the argument."

Nichols also says, "Our observations show a burst of auroras that are moving very, very quickly across the polar region of the planet. We can see that the magnetotail is undergoing huge turmoil and reconfiguration, caused by buffering from solar wind. It's the smoking gun that shows us that the tail is collapsing."

The research will be published here in Geophysical Research Letters.

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