A team of scientists led by Artem Oganov, a professor at the Skolkovo Institute of Science and Technology (Skoltech), has used computer modelling to describe what materials make up the interiors of Uranus and Neptune, as well as their icy satellites.
A diagram showing the scientists' findings regarding the interior structure of Uranus. Image: Skoltech.
Their findings were published in the Scientific Reports research journal last week in a report jointly authored by Oganov and Gabriele Saleh, a professor at the Moscow Institute of Physics and Technology, where Oganov heads up the Computational Materials Discovery Lab.
The scientists uncovered new stable polymorphs of high-pressure elements and known molecules, using the evolutionary algorithm USPEX (Universal Structure Predictor Evolutionary Xtallography) developed by Oganov, as well as supercomputers including MIPT’s Rurik machine, to establish which compounds would be formed at the high pressures characteristic of the planets. They found that these would include carbonic acid and orthocarbonic acid.
"The smaller gas giants – Uranus and Neptune – consist largely of carbon, hydrogen and oxygen. We have found that at a pressure of several million atmospheres, unexpected compounds should form in their interiors. The cores of these planets may largely consist of these exotic materials," says Oganov, the study’s lead author.
"This is an extremely important system, because all organic chemistry rests on these three elements, and until now it had not been entirely clear how they behave under extreme pressures and temperatures. In addition, they play an essential role in the chemistry of the giant planets," he said.
Oganov says it’s possible that the cores of Neptune and Uranus contain significant amounts of a polymer of carbonic acid and orthocarbonic acid.
“This novel chemistry should have major implications for planetary science,” the scientists concluded at the end of their article, titled “Stable Compounds in the C-H-O Ternary System at High Pressure.”