Sparkling diamond rain which was theorised to fall on Neptune and Uranus has been created in the laboratory for the first time by scientists.
A team from the US, the UK and Germany recreated the conditions found deep inside the icy giant planets of the Solar System and watched as tiny diamonds formed.
It was always thought that the extreme high pressures on Neptune and Uranus would squeeze the carbon atoms in the atmosphere, allowing diamond rain to fall, which possibly clumps in a glittering mass around the core.
But until now, nobody had ever watched it happen.
To create the ‘rain’, scientists used a sheet of polystyrene which contains similar intense quantities carbon and the shocked it with extreme soundwaves to recreate the high pressure of the outer planets.
Nearly every carbon atom turned into a small diamond of a few nanometers wide. On Uranus and Neptune, the study authors predict that diamonds would become much larger, maybe millions of carats in weight.
“We can’t go inside the planets and look at them, so these laboratory experiments complement satellite and telescope observations,” said Dr Dominik Kraus, scientist at Helmholtz Zentrum Dresden-Rossendorf, Germany, and lead author on the publication.
“Previously, researchers could only assume that the diamonds had formed. When I saw the results of this latest experiment, it was one of the best moments of my scientific career.”
Researchers think it’s possible that over thousands of years, the diamonds slowly sink through the planets’ ice layers and assemble into a thick layer around the core.
In the experiment, the polystyrene was used to simulate methane - a compound made from molecules of carbon and hydrogen that is abundant in the outer planets, and which even causes the distinct blue colour of Neptune. In its inner layers methane forms hydrocarbon chains, which were believed to turn into diamonds at high pressure.
During the experiment the polystyrene was x-rayed using one of the brightest machine in the world to see the diamonds., which is housed at the SLAC National Accelerator Laboratory at Stanford University.
“You need these intense, fast pulses of X-rays to unambiguously see the structure of these diamonds, because they are only formed in the laboratory for such a very short time,” said Siegfried Glenzer, professor of photon science at Stanford University.
The experts say that the nanodiamonds made on Earth could potentially be harvested to make the tips of precision medical instruments, or used in electronics.
Researchers from the University of Warwick were also involved in the project. The research published in Nature Astronomy on August 21.
A separate study by Stanford University and French scientists found that it snows on Mars at night. Computer modelling of the climate suggests that 'microbusts' of snowfall can occur on the red planet due to the cooling of cloud water ice particles during the night.
Scientists now believe that turbulent storms, which can only form at night, act to vigorously mix the atmosphere and, in some places, deposit snow on the Martian surface.
The proposed process also sheds light on the previously unexplained precipitation signatures detected by NASA’s Phoenix lander. The research was published in Nature Geoscience.