An artist's depiction shows a robot mining for diamonds on Saturn. (Michael Carroll)
While we're stuck with water, in much of the the solar system, it's raining diamonds.
For decades, planetary scientists have used pressure and temperature data from Neptune and Uranus to theorize that a layer of diamond bits settled on the planets’ cores (though those findings are still debated). Now, using new data, planetary scientists Mona Delitsky and Kevin Baines have demonstrated that diamonds can remain stable on Saturn and Jupiter, too.
“We know that inside the clouds on Saturn is pure carbon,” Baines, a scientist at University of Wisconsin-Madison and the Jet Propulsion Laboratory, told Weather.com. “There’s gravity there so obviously those solid carbon particles have to rain down. So we just said when they get down deep enough they should turn into diamonds. It all kind of just fell naturally from thunderstorms on Saturn.”
Storms on Saturn are among the most violent in the solar system, lofting ice 100 miles into the air and shocking the planet with lightning strikes. Saturn’s atmosphere contains a small percentage of methane, whose chemical makeup consists of carbon and hydrogen. When lightning strikes the atmosphere, the carbon and hydrogen separate, leaving isolated carbon atoms to float around and accumulate like flakes of snow in a blizzard.
As the carbon nuggets fall through ever-increasing temperatures and pressures, they form into graphite — the stuff at the tip of your pencil — and pull more carbon atoms from the atmosphere. Eventually, around 6,000 kilometers in, the pressure compresses them into bits of diamond that drift slowly through Saturn’s dense layers.
The diamond maintains its structure until about 36,000 kilometers in. Once it reaches this point, the temperature is hotter than the sun’s surface, and the diamond breaks down. “At that point the diamond turns back into a liquid, mushy kind of substance,” Baines said.
Baines estimates that most of the diamond pieces are smaller than a millimeter across, with about 1 percent reaching a centimeter and a few outliers growing up to 10 centimeters. Overall, rough estimates show that lightning strikes on Saturn generate about 1,000 tons of diamond each year. There could be other sources of carbon, Baines notes, and his calculations don’t take into account these sources.
The same process occurs on Jupiter, but the conditions there are not as favorable for diamond production as on Saturn, Baines said.
In Baines’ view, a future civilization could figure out how to mine the diamond, making it as common as iron and steel are today. In such a future, Earth’s liquid water would be the true valuable commodity. “So it’s raining diamonds on Saturn and, ho hum, it’s raining diamonds everywhere,” Baines said. “What’s the big deal?”
Delitsky and Baines presented their results today at the annual meeting of the American Astronomical Society’s Division for Planetary Sciences.
MORE: Saturn Imagery
NASA's Cassini spacecraft snapped this view of a monster hurricane at Saturn's North Pole. The eye of the cyclone is 1,250 miles across. That's 20 times larger than the typical eye of a hurricane here on Earth. The hurricane is believed to have been there for years. (AP Photo/NASA/JPL-Caltech/SSI)