NASA-International Space Station

Auroras occur on Earth, Jupiter, Saturn and a few other planets, and the innovative images will help scientists improved understand how they are generated.

An Aurora

"The auroras have put on a amazing show, shape-shifting rapidly and exposing curtains that were suspected to be there, but hadn't seen on Saturn before," said Andrew Ingersoll of the California Institute of Technology in Pasadena, who is a member of the Cassini imaging team that processed the latest video. "Seeing these things on a new planet helps us understand them a little better when we see them on Earth."

Auroras appear generally in the high latitudes near a planet's magnetic poles. When charged particles from the magnetosphere the magnetic bubble surrounding a planet plunge into the planet's higher atmosphere, they cause the atmosphere to glow. The curtain shapes prove the paths that these charged particles take as they flow along the lines of the magnetic field between the magnetosphere and the topmost part of the atmosphere.

An aurora above the northern part of Saturn

The height of the curtains on Saturn exposes a key distinction between Saturn's atmosphere and our own, Ingersoll said. While Earth's atmosphere has a lot of oxygen and nitrogen, Saturn's atmosphere is composed chiefly of hydrogen. Because hydrogen is very light, the atmosphere and auroras reach extreme out from Saturn. Earth's auroras tend to flare only about 100 to 500 kilometers over the surface.

The speed of the auroral changes in the video is similar to some of those on Earth, but scientists are still working to understand the processes that produce these quick changes. The height will also help them discover how much energy is necessary to light up auroras.

Ultraviolet and infrared instruments on Cassini have captured images of and data from Saturn's auroras before, but in these newest images, Cassini's narrow-angle camera was able to confine the northern lights in the noticeable part of the light spectrum, in higher resolution.

The images were initially obtained in black and white, and the imaging team highlighted the auroras in false-color orange. The oxygen and nitrogen in Earth's upper atmosphere add to the colorful flashes of green, red and even purple in auroras. But scientists are still operational to determine the true color of the auroras at Saturn, whose atmosphere lacks those chemicals.