Diamond Crystals the Size of Hailstones Rain Down From the Atmospheres of Jupiter and Saturn, Says NASA ScientistOctober 19, 2013
Lightning storms in the upper atmosphere of Jupiter and Saturn are responsible for initiating the process that eventually yields a diamond. When lightning strikes methane the gas is turned into soot, or carbon.
“As the soot falls, the pressure on it increases,” said Kevin Baines of the University of Wisconsin-Madison and NASA’s Jet Propulsion Laboratory. “And after about 1,000 miles it turns to graphite — the sheet-like form of carbon you find in pencils.”
As it falls farther — 4,000 miles or so — the pressure is so intense that the graphite toughens into diamond, strong and unreactive, according to Baines.
The biggest diamond crystals falling through the atmosphere of Jupiter and Saturn would likely be about a centimeter in diameter — “big enough to put on a ring, although, of course, they would be uncut,” said Baines.
Because Jupiter and Saturn are made of gas and are hotter than the Sun at their cores, what happens next to the falling diamonds is hard to believe. As they descend another 20,000 miles into the core of the planets, they eventually melt into a sea of liquid carbon.
“Once you get down to those extreme depths, the pressure and temperature is so hellish, there’s no way the diamonds could remain solid,” he said.
Baines and Mona Delitsky of California Specialty Engineering presented their findings at the annual meeting of the American Astronomical Society in Denver.
“People ask me, ‘How can you really tell? Because there’s no way you can go and observe it,’” Baines said.
“It all boils down to the chemistry,” he concluded. “And we think we’re pretty certain.”