Saturn doesn't 'look its age' because of internal composition

EXETER, England, April 30 (UPI) -- Astronomers trying to understand why Saturn "appears young," brighter than it should, say gas generated deep within keeps it looking young and hot.

Planets become darker and cooler as they age, but Saturn is much brighter than expected for a planet of its age, researchers in Britain and France said.

Scientists from the University of Exeter and the Ecole Normale Superieure de Lyon say they've determined layers of gas generated by physical instability deep within the giant planet prevent heat from escaping and slow Saturn's cooling rate.

"Scientists have been wondering for years if Saturn was using an additional source of energy to look so bright but instead our calculations show that Saturn appears young because it can't cool down," Exeter researcher Gilles Chabrier said in an Exeter release Tuesday.

"These separate [gas] layers effectively insulate the planet and prevent heat from radiating out efficiently," Chabrier said. "This keeps Saturn warm and bright."

The researchers say their findings suggest the interior structure, composition and thermal evolution of giant planets in our Solar System and elsewhere may be much more complex than previously thought.