This image shows a ring of auroral lights glowing above the South Pole of Saturn. The aurora, shown here in blue, was actually photographed in ultraviolet "light". This image, captured by the Hubble Space Telescope in 2004, is a composite of the UV auroral image combined with a visual light image of the rest of Saturn. Click on image for full size (40 Kb) Image courtesy of NASA, ESA, J. Clarke (Boston University), and Z. Levay (STScI).

Have you ever seen the Southern or Northern Lights? Did you know that Earth isn't the only planet that puts on these beautiful light shows, also known as the "aurora"? Auroral displays have also been observed at both poles of Saturn.

Charged particles in the solar wind become trapped within Saturn's magnetosphere by the ringed planet's powerful magnetic field. Energetic electrons are accelerated to high speeds as they ricochet along magnetic field lines. Saturn's magnetic field steers the particles towards the planet's poles, where the particles collide with hydrogen gas in the planet's upper atmosphere. Energy from the electrons makes the hydrogen gas glow; the phenomenon is similar to the way a fluorescent light glows when electricity flows through it.

Aurora on Earth typically shine for a few hours at most, but the ones on Saturn can go on for days. Auroral "curtains" can rise 1,200 miles (2,000 km) above the cloud tops near Saturn's poles. An observer on Saturn would see the aurora as a faint red glow. However, Saturn's aurora emit much more energy at ultraviolet (UV) wavelengths than they do in the visible part of the spectrum. Our observations, therefore, of Saturn's aurora have been primarily at UV wavelengths.

The Hubble Space Telescope and the International Ultraviolet Explorer (IUE) telescope both observed Saturn's UV aurora from Earth orbit. Hubble captured the first images of the aurora in 1995. The Pioneer 11, Voyager 1 & 2, and Cassini interplanetary spacecraft observed Saturn's aurora from closer range. Since most UV radiation cannot penetrate Earth's atmosphere, ground-based telescopes are not able to "see" Saturn's aurora.

At Earth, the auroral lights are mostly produced by collisions between energetic particles and either nitrogen or oxygen in our atmosphere. Saturn's aurora are generated when electrons crash into hydrogen molecules and atoms in that planet's upper atmosphere. Scientists have also detected radio signals emitted by Saturn's aurora, much like the static one sometimes hears in radio broadcasts when lightning strikes nearby.

This picture shows the aurora (Southern Lights) of Saturn. The aurora looks like a blue ring of light over Saturn's South Pole in this picture. The Hubble Space Telescope took this picture in 2004. Click on image for full size (40 Kb) Image courtesy of NASA, ESA, J. Clarke (Boston University), and Z. Levay (STScI).

Have you ever seen the Southern or Northern Lights? Earth isn't the only planet that puts on these beautiful light shows, which are also called the "aurora". Aurora have been seen at both poles of Saturn, too.

The solar wind is a flow of charged particles that stream outwards from the Sun. When they get to Saturn, some of those particles are trapped by Saturn's magnetic field. Fast-moving electrons bounce back and forth in Saturn's magnetic field, gaining more and more energy. Some of them blast into Saturn's atmosphere near the planet's poles. The electrons cause hydrogen gas in the atmosphere to glow. It is a lot like the glow that lights a fluorescent bulb when electricity flows through it.

Aurora on Earth usually shine for a few hours at most. Aurora on Saturn can last for days! These "curtains of light" sometimes rise 1,200 miles (2,000 km) above the cloud tops near Saturn's poles. If you were on Saturn, the aurora would look like a faint red glow. Most of the energy in Saturn's aurora is not in the form of visible light, though. Instead, they mostly glow in ultraviolet (UV) wavelengths.

Most UV "light" cannot get through Earth's atmosphere. That means telescopes on the ground cannot see Saturn's UV aurora. However, telescopes in Earth orbit can. Spacecraft that fly near Saturn can also "see" the ringed planet's aurora. The Hubble Space Telescope has taken some pictures of Saturn's aurora. The Pioneer 11, Voyager 1 & 2, and Cassini spacecraft have observed Saturn's aurora from closer range.

The aurora at Earth are mostly caused when high-energy particles collide with either nitrogen or oxygen in our atmosphere. Saturn's aurora are caused by electrons crashing into hydrogen molecules and atoms in Saturn's upper atmosphere. Scientists have also detected radio signals emitted by Saturn's aurora. It is a lot like the static you can sometimes hear on a radio when lightning strikes nearby.

This picture shows the aurora (Southern Lights) of Saturn. The aurora looks like a blue ring of light over Saturn's South Pole in this picture. The Hubble Space Telescope took this picture in 2004. Click on image for full size (40 Kb) Image courtesy of NASA, ESA, J. Clarke (Boston University), and Z. Levay (STScI).

Have you ever seen the Southern or Northern Lights? Did you know that other planets (besides Earth) have them too? Scientists call these cosmic light shows the "aurora". Saturn is one of the planets that has aurora.

The Sun shoots out lots of charged particles. That flow of particles is called the "solar wind". When the solar wind gets to Saturn, some of the particles get trapped in Saturn's magnetic field. Some particles crash into gases in Saturn's atmosphere near the planet's North and South Poles. That makes the gases glow, sort of like a fluorescent light bulb. That glow is the aurora.

The aurora on Saturn are much larger and last longer than the ones on Earth. Most of the energy coming from Saturn's aurora is not visible light. Instead, it is ultraviolet (UV) "light". Scientists use special telescopes and cameras to "see" the UV radiation.

The Hubble Space Telescope has taken some pictures of Saturn's aurora. The Pioneer 11, Voyager 1 & 2, and Cassini spacecraft have also observed Saturn's aurora.