Scientists have demonstrated in the laboratory "diamond fall" - a strange phenomenon, which, according to the predictions of the theory, should be observed on Uranus and Neptune.
The atmospheres of the ice giants contain significant amounts of methane and other volatile organics. Simulations show that at a depth of thousands of kilometers, where the pressure reaches a suitable level, they and hydrogen can lead to diamond crystals forming rather quickly and falling out in the form of something like snow.
Using a laser from the US National Accelerator Laboratory SLAC, Dominik Kraus and his colleagues demonstrated this process under controlled conditions. The details of their work are described in an article published in the journal Nature Astronomy.
High-power laser pulses aimed at a plastic, polystyrene sample created two successive shock waves in it. The second was larger and faster than the first and at the right moment caught up with it. The interference of these waves created both deep depressions of low pressure and peaks of ultrahigh pressure, where the formation of short-lived diamond crystals took place. The LCLS tool made it possible to follow the process, taking “snapshots” billions of times per second.
Experience has shown that the formation of diamonds took place at temperatures of hundreds of thousands of degrees and pressures of the order of a million atmospheres - almost an order of magnitude higher than it was possible to obtain in such experiments before. Similar conditions can exist in the atmospheres of ice giants at a depth of about 10 thousand km. According to Dr. Kraus, this process could occur even at almost absolute zero, but would require even much higher pressure.
You can't get rich in the production of such diamonds from plastic: the size of the crystals did not exceed a few nanometers. But in the atmospheres of Neptune and Uranus, they, according to theoretical calculations, can be much larger, reaching hundreds of kilograms of mass. The solid cores of these giant planets are surrounded by a thick layer of a mixture of ice under tremendous pressure, through which giant diamonds are slowly falling. They may even accumulate below, surrounding the core with a stunning diamond crust.
Sergey Vasiliev