Using one of the most powerful lasers in the world, the OMEGA laser – it is an ultra-intense laser – from the Energy Lasers Laboratory of the University of Rochester in New York (USA), a team of physicists from the Lawrence National Laboratory Livermore (LLNL) in Livermore, California (USA) has achieved the first experimental evidence of helium “rain” on the planet Saturn, a phenomenon in which a mixture of liquid hydrogen and helium separates the helium droplets in the atmosphere of the planet as if it were the mixture of oil and water.
Scientists have been theorizing about helium rain on the planet Saturn since the mid-1970s , but until now the experimental evidence had failed. “It is a surprise that this occurs in such a wide regime of such temperatures and densities. Something was happening with the conductivity, ”explains Gilbert Collins, an extreme matter physicist at LLNL and a leader on the paper.
For Saturn’s temperature, the planet is 50% brighter than it should be. One way to explain this extra glow would be through the behavior of its massive envelope of hydrogen and helium gases. As temperatures and pressures rise inside the planet, these gases turn into a liquid state and at levels much deeper still, the already liquid hydrogen becomes an electrically conductive or metallic material, while the helium remains mixed. .
However, when atmospheric conditions exceed a certain threshold of pressures and temperatures, liquid helium falls from this mixture in the form of rain . Thus, according to this theory, the liquid helium droplets would form a kind of rain that would unleash the gravitational potential energy, making the sixth planet in the Solar System brighter than it should.
To arrive at these results, which showed that this event could also be found on Jupiter, the scientists needed about 5 years and 300 laser shots to sketch this phase transition with temperatures between 3,000 and 20,000 º Kelvin and pressures between 30 and 300 gigapascals.
The findings, which for all have been “unexpected and exciting,” appear in the journal Science and were presented at the meeting of the American Geophysical Union in San Francisco, California.
