The stunning space phenomenon 'diamond rain' may be more common than once thought

Diamonds are forever, but they might not be that rare.

Diamonds are forever, the saying goes.

The precious stones may also be surprisingly abundant throughout the universe, a press statement reveals. Scientists have used common plastic to recreate the process that leads to diamond rain on Uranus and Neptune in the lab. They found that it is likely diamonds actually form in these planets' atmospheres.

Previously, the consensus was that high pressure and temperature conditions deep below the surface of these ice giants turn hydrogen and carbon into solid diamonds.

Now, the new research published in Science Advances shows that "diamond rain" may be more common than once thought, thanks to the effects of oxygen.

Replicating the diamond rain process

Ice giants are thought to be the most common type of planet outside of our solar system. This means that, based on the new research, diamond rain may be occurring throughout the universe on a much larger scale than previously thought.

According to Dominik Kraus, a physicist at Germany's HZDR research lab and one of the study's authors, diamond rain is a very different process from regular precipitation on Earth. Kraus and a team replicated this process in the lab using PET plastic, which has the necessary mix of carbon, hydrogen, and oxygen.

The team focused a high-powered optical laser on the plastic at the SLAC National Accelerator Laboratory in California. "Very, very short X-ray flashes of incredible brightness" allowed them to replicate and observe the process of nanodiamond formation, according to Kraus. Nanodiamonds are tiny diamonds too small to see with the naked eye.

"The oxygen that is present in large amounts on those planets really helps suck away the hydrogen atoms from the carbon, so it's actually easier for those diamonds to form," he continued.

A new method for producing nanodiamonds

Their experiment could provide a new method for producing nanodiamonds on Earth. This could be highly valuable, as nanodiamonds have a wide and growing range of applications in drug delivery, medical sensors, non-invasive surgery, and quantum electronics.

"The way nanodiamonds are currently made is by taking a bunch of carbon or diamond and blowing it up with explosives," said SLAC scientist and study co-author Benjamin Ofori-Okai.

"Laser production could offer a cleaner and more easily controlled method to produce nanodiamonds," he added.

Of course, the research on Neptune and Uranus' diamond rain remains hypothetical as the scientific community does not have a huge amount of close-up observational data on the two planets. The only spacecraft to perform a flyby of both planets to date is NASA's Voyager 2 in the 1980s. The space agency does aim to go back to the planets in the 2030s, though, meaning that we may soon know a whole lot more about diamond precipitation and the abundance of the precious material throughout the cosmos.