NASA probe gets 360-degree view of Saturn's auroras

NASA trained several pairs of eyes on Saturn as the planet put on a dancing light show at its poles.

While NASA's Hubble Space Telescope, orbiting around Earth, was able to observe the northern auroras in ultraviolet wavelengths, NASA's Cassini spacecraft, orbiting around Saturn, got complementary close-up views in infrared, visible-light and ultraviolet wavelengths. Cassini could also see northern and southern parts of Saturn that don't face Earth.

Jonathan Nichols of the University of Leicester in England, who led the work on the Hubble images, said that Saturn's auroras can be fickle-you may see fireworks, you may see nothing.

He said that 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 Hubble and Cassini images were focused on April and May of 2013. Images from Cassini's ultraviolet imaging spectrometer (UVIS), obtained from an unusually close range of about six Saturn radii, provided a look at the changing patterns of faint emissions on scales of a few hundred miles (kilometers) and tied the changes in the auroras to the fluctuating wind of charged particles blowing off the Sun and flowing past Saturn.

Sarah Badman, a Cassini visual and infrared mapping spectrometer team associate at Lancaster University, England, said that 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.

She said that 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.