Scientists Recreate Neptune’s Diamond Rain Effect for the First Time

With the help of X-ray lasers, Stanford’s SLAC National Accelerator Laboratory has recreated conditions on Neptune and successfully observed the formation of a diamond rain. The work supports a popular hypothesis about the chemical processes going on inside the planet.

Scientists have long suspected that some planets in our solar system, Neptune and Uranus in particular, are hiding a sparkly layer of pure diamond close to their solid cores.

They suggest that extreme pressures and blazing temperatures deep within the icy giants would act on hydrogen and carbon to form diamonds that rain downwards, sinking toward the planets' interiors.

Until now, there hasn't been enough evidence to back up the hypothesis, but a large international research team has managed to precisely recreate the temperatures and pressures of the planets by using the SLAC X-ray laser facility to successfully produce and then examine the diamond rain.

"Previously, researchers could only assume that the diamonds had formed," according to lead researcher Dominik Kraus, from Helmholtz Zentrum Dresden-Rossendorf in Germany, cited by Business Insider.

"When I saw the results of this latest experiment, it was one of the best moments of my scientific career."

To mimic the effect, researchers used an intense laser to send two shockwaves through polystyrene — a plastic made from hydrogen and carbon. When the two shockwaves caught up with each other, they created a short moment of pressure and heat similar to conditions thought to exist 10,000km beneath the surface of Neptune. In the result, nearly every carbon atom in the plastic was incorporated into diamond structures just a few nanometers wide. But scientists claim that on Neptune and Uranus, where conditions are more stable, the rocks grow up to millions of carats in weight.

The experimental time is very short, but scientists were able to capture the moment of diamond formation, thanks to SLAC's powerful Linac Coherent Light Source (LCLS).

Although the study was initially launched to learn more about the nature of the planets that form our solar system, it may eventually contribute to the production of readily and cheaply accessible diamonds here on Earth.