Metallic rain could explain Saturn’s two-billion-year age gap

The mystery behind the ringed planet’s ‘youth’ may have been solved

Saturn's 'youth' could be explained by the warming effect of helium rain. Image Credit: NASA

Saturn’s ‘youth’ could be explained by the warming effect of helium rain. Image Credit: NASA

The reason behind why Saturn is hotter than it should be, given that it doesn’t have any heating source except for the Sun, could be explained by the warming effect of metallic helium rain according to researchers at the Sandia National Laboratories in Albuquerque, New Mexico.

The ringed giant has puzzled astronomers ever since the unexplained heat caused a two-billion-year discrepancy for computer models trying to obtain an accurate number for Saturn’s age. “Models that correctly predict Jupiter to be a 4.5 billion years old find Saturn to be only 2.5 billion years old,” explains Sandia’s Thomas Mattsson.

Using an experiment known as the Z machine, a facility based at Sandia that uses strong magnetic fields to produce high temperatures, high pressures and extremely power, Mattsson and his team verified an 80-year proposition: that molecular hydrogen becomes metallic if squeezed by enough pressure. “That long-ago prediction would explain Saturn’s temperature because when hydrogen [becomes metallic] and mixes with helium in a dense liquid, it can release helium rain,” says Mike Desjarlais. “Helium rain is an energy source that can alter the evolution of a planet.”

“Essentially, helium rain would keep Saturn warmer than calculations of planetary age alone would predict,” adds Marcus Knudson, also at Sandia.

While the work by the team shows that dense hydrogen can be metallic, which in turn changes the coexistence of abundant elements hydrogen and helium in Saturn’s atmosphere, the results need further confirmation.

“The mechanism of helium rain that has been proposed is therefore very plausible, given our results, but the scientific discussion will continue over the next few years in establishing a new consensus,” concludes Mattsson.

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