The international group of scientists from France and the United States received testimonies in favor of the hypothesis, according to which helium rains are possible on Jupiter and Saturn. For the first time, the existence of this exotic phenomenon was offered almost 40 years ago, but there was still no experimental confirmation. The article with the results of the study was published in the journal Nature.
During the experiment, astrophysics reproduced the pressure of four gigapascals in cells with diamond anvils for compressing a mixture of hydrogen and helium. With the help of laser rays, the sample was exposed to shock waves for even greater compression to the final pressure of 60-180 gigapascals and temperatures more than ten thousand Kelvinov. Such conditions are present in the lower layers of the atmosphere of gas giants.
Researchers discovered a sharp change in the reflectivity of the sample at a pressure of 150 gigapascals and a temperature of 10,200 Kelvinov, which is a sign of separation of a mixture of hydrogen and helium. Under similar conditions that are present in the depths of Jupiter (at a depth, corresponding to 15 percent of the planet radius), hydrogen turns into a metal fluid, and it triggers the stratification process of the mixture and precipitation of helium.
Helium rains can explain the excess luminosity of Saturn and the depletion of helium and neon in the atmosphere of Jupiter, as was recorded by the Galileo probe.