Diamond rain, seas and even 鈥渄iamondbergs鈥� could be floating inside Jupiter and Saturn, according to new analysis of how carbon behaves at high temperatures and pressures. Neptune and Uranus may already play host to diamonds, so the latest results could mean all of the solar system鈥檚 gas giants are littered with bling.
鈥淧eople have been talking about diamonds in Uranus and Neptune for 30 years,鈥� says Mona Delitsky of California Specialty Engineering in Pasadena. That鈥檚 because atmospheric models for these two planets suggest pressure and temperature conditions are extreme enough to crush carbon into diamond, but the picture was less clear for other planets. 鈥淔or Jupiter and Saturn there was not enough information.鈥�
In recent years, however, our knowledge of carbon鈥檚 behaviour under extreme conditions has been extended by research at places like the Sandia National Laboratories in Albuquerque, New Mexico, which has a machine that can melt diamonds. Delitsky and her colleague Kevin Baines of the University of Wisconsin-Madison have combined data from their research with new models of Jupiter and Saturn鈥檚 atmospheres and say both planets may have diamonds as well.
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The pair say lighting storms on Saturn split methane in the upper atmosphere, producing soot 鈥渞ain鈥�. As the soot falls through the atmosphere and into the gas giant鈥檚 interior, pressure and temperature increase, which Delitsky and Baines believe crushes the soot particles into diamonds. The diamonds keep on growing as they fall until they are large enough to be called diamondbergs.
Eventually, the mammoth gems would reach regions near Saturn鈥檚 core where temperatures are a blistering 8000 kelvin and pressures are 500 gigapascals 鈥� 5 million times as great as at Earth鈥檚 surface 鈥� conditions hot enough to melt the diamond.
Delitsky presented the results at the meeting in Denver, Colorado today.
Not everyone is convinced. Just because diamonds can exist doesn鈥檛 mean they do, says Luca Ghiringhelli of the Fritz Haber Institute of the Max Planck Society in Berlin, Germany, who has also questioned the presence of the gems on Uranus and Pluto. It is not clear that an initial diamond nucleus could form to grow into a larger stone, he says. 鈥淥n Jupiter and Saturn they may melt in the interior, but somebody [would have to] put them there first as there are no conditions for their formation.鈥�
