Saturn's Auroras Imaged in 360-Degree Detail by NASA Spacecraft [VIDEO]

A joint observation effort between NASA's Hubble Space Telescope and the Cassini spacecraft in orbit around Saturn has provided astronomers with the most comprehensive picture ever taken of the ringed planet's auroras.

Auroras on Saturn occur like they do on Earth, when energized solar particles slam into atoms in the atmosphere, particularly along high latitudes.

Saturn's aurora have been documented before, but this latest endeavor - which took place during April and May of 2013 - brings together observations in ultraviolet wavelengths from the Hubble telescope and complementary close-up views in infrared, visible-light and ultraviolet wavelengths obtained by Cassini.

"Saturn's auroras can be fickle -- you may see fireworks, you may see nothing," said Jonathan Nichols of the University of Leicester in England, who led the work on the Hubble images. "In 2013, we were treated to a veritable smorgasbord of dancing auroras, from steadily shining rings to super-fast bursts of light shooting across the pole."

The joint observation allowed researchers to view the aurora on the scale of just a few hundred miles. The images also reveal fluctuations in the aurora caused by changes in solar winds in clear detail.

"This is our best look yet at the rapidly changing patterns of auroral emission," said Wayne Pryor, a Cassini co-investigator at Central Arizona College in Coolidge, Ariz. "Some bright spots come and go from image to image. Other bright features persist and rotate around the pole, but at a rate slower than Saturn's rotation."

The new data also give astronomers an idea about why the gases on Saturn can reach such high temperatures considering the planet's distance from the Sun.

"Scientists have wondered why the high atmospheres of Saturn and other gas giants are heated far beyond what might normally be expected by their distance from the Sun," said Sarah Badman, a Cassini visual and infrared mapping spectrometer team associate at Lancaster University, England. "By looking at these long sequences of images taken by different instruments, we can discover where the aurora heats the atmosphere as the particles dive into it and how long the cooking occurs."

The Cassini probe's visible-light images revealed the color of Saturn's auroras. While auroras on Earth are typically green on the bottom and red on top, Saturn's are red at the bottom and purple on top. The color difference is due to a difference in molecules in the planet's upper atmospheres, with Earth's being dominated by nitrogen and oxygen and Saturn's full of hydrogen.

"While we expected to see some red in Saturn's aurora because hydrogen emits some red light when it gets excited, we also knew there could be color variations depending on the energies of the charged particles bombarding the atmosphere and the density of the atmosphere," said Ulyana Dyudina, an imaging team associate at the California Institute of Technology, Pasadena, Calif. "We were thrilled to learn about this colorful display that no one had seen before."

In the future, the Saturn researchers hope to learn how clouds of charged particles move around the ringed planet as it rotates and receives blasts of solar particles.

"The auroras at Saturn are some of the planet's most glamorous features -- and there was no escaping NASA's paparazzi-like attention," said Marcia Burton, a Cassini fields and particles scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif., who is helping to coordinate these observations. "As we move into the part of the 11-year solar cycle where the sun is sending out more blobs of plasma, we hope to sort out the differences between the effects of solar activity and the internal dynamics of the Saturn system."