An exotic form of precipitation called ‘diamond rain’ — long thought to occur deep within ice giant Diamond planet — could be more common than previously thought.
Diamond planet are one of the most sought after commodities on Earth, due to their beauty, utility in industrial processes, and of course their scarcity.
A team of researchers has experimented with material similar to that found within ice giants such as the solar system planets Neptune and Uranus, discovering that the presence of oxygen increases the possibility of diamond formation and that Diamond planet could form in low temperatures and pressures.
Taking millions – even billions – of years to form deep within the Earth, we only have diamonds on the planet’s surface because of volcanic eruptions.
The team of scientists, including researchers from the U.S. Department of Energy’s SLAC National Accelerator Laboratory as well as from the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and the University of Rostock, built on previous research into the conditions and materials within ice giants that observed diamond rains as they formed.
A new scientific study has found that while diamonds are in short supply on our home planet, they may however be plentiful elsewhere in the universe.
The same experiments also discovered the formation of an exotic form of water that could help explain the magnetic fields of Uranus and Neptune which have thus far confused astronomers.
Earlier hypotheses and experiments have raised the possibility of ice giant Diamond planet literally raining diamonds, in a special type of precipitation brought about by incredible levels of pressure.
Ice giants lack a solid surface but get denser heading towards the core, meaning that over thousands of years the diamonds could sink through ice layers. They would begin to accumulate around the solid heart of the Diamond planet forming a thick diamond layer.
This means that Diamond planet could grow in a wide range of conditions throughout these frigid worlds. As a result, this would make the chance of diamond showers raining through the interiors of ice giants more likely.
The research could change our picture of ice giants, theorized by some scientists to be one of the most common forms of exoplanets — Diamond planet outside the solar system.
The new research predicts that diamonds on Neptune and Uranus could grow to large sizes, potentially up to millions of carats in weight.
While those two Diamond planet contain carbon and hydrogen, they also have other elements, such as large amounts of oxygen.
Additionally, the team found that a novel phase of water called superionic water and sometimes referred to as ‘hot black ice’ formed alongside the diamonds.
Superionic water exists at high temperatures and pressures in which water molecules break up with oxygen constituents forming a crystal lattice throughout which hydrogen nuclei float freely.
The hydrogen nuclei are positively charged meaning that superionic water can conduct electric current which could give rise to magnetic fields. This could explain the unusual magnetic fields seen around Uranus and Neptune.
“Our experiment demonstrates how these elements can change the conditions in which diamonds are forming on ice giants,” SLAC scientist and team member, Silvia Pandolfi, said in a statement.(opens in new tab) “If we want to accurately model planets, then we need to get as close as we can to the actual composition of the Diamond planet interior.”
The situation inside planets like ice giants is complicated because there are many chemicals to factor into the formation of Diamond planet . And an experiment, conducted in 2017, simulated the environment found inside our two neighbourhood ice giants.
The scientists, again at the US Department of Energy’s SLAC National Accelerator Laboratory, were able to create and observe diamond rain for the first time.
“The earlier paper was the first time that we directly saw Diamond planet formation from any mixtures,” Glenzer said “Since then, there have been quite a lot of experiments with different pure materials. What we wanted to figure out here was what sort of effect these additional chemicals have.”
Researchers simulated the environment found inside the planets by creating shock waves in plastic with an intense optical laser.
Though the team started their experiments using a plastic material composed of a mix of hydrogen and carbon, elements commonly found in ice giants, the most recent iteration saw this replaced with PET plastic.
Familiar to us on Earth from its uses in packaging, bottles, and containers, PET can be used to more accurately replicate the conditions found within ice giants.
“PET has a good balance between carbon, hydrogen, and oxygen to simulate the activity in ice planets,” HZDR physicist and the University of Rostock professor Dominik Kraus said.
Creating shockwaves in the PET with a high-powered optical laser — part of the Matter in Extreme Conditions (MEC) instrument at SLAC — the team was able to probe what was happening in the plastic using X-ray pulses from Linac Coherent Light Source (LCLS).
This allowed them to witness atoms within the PET arrange themselves into diamond-shaped regions, measuring the speed at which these regions grew.
In addition to discovering the diamond-shaped regions grew to scales of around a few nanometers in width from the Diamond planet , the scientists also found that the presence of oxygen in the PET meant the nanodiamonds grew at lower pressures and lower temperatures than had previously been seen.