If you’ve ever fantasized about diamonds raining down from the sky, it actually does happen. There is diamond rain on Uranus and Neptune. Like, solid diamonds.
Scientists have finally proven this isn’t just a daydream inspired by Breakfast at Tiffany’s. For decades, it was assumed this phenomenon happened on the ice giants, and past experiments have not been able to replicate it perfectly. Now a team at Stanford University’s SLAC National Accelerator Laboratory is finally living the dream after an experiment that joined forces between a superpowered optical laser and an X-ray free-electron laser (Linac Coherent Light Source or LCLS) to successfully re-create the exact process right here on Earth.
LCLS produces ultra-fast X-ray pulses—as in a million-billionths of a second—that let the team monitor the process with unreal precision down to an atomic scale. Making it rain diamonds is much less glamorous than it sounds. Polystyrene foam was used because hydrogen and carbon are elements in polystyrene that are also found everywhere inside Neptune and Uranus in the form of methane. With four hydrogen atoms and one carbon atom, atmospheric methane molecules in these planets were thought to form hydrocarbon chains which the right temperature and pressure would transform into diamonds. Turns out the theory was right on.
The team used an optical laser to induce two successive shock waves into the polystyrene at the temperatures and pressures found in the atmospheres of these planets. They then zapped it with X-ray pulses, and where the shockwaves overlapped and created higher pressure, nanodiamonds emerged.
“For this experiment, we had LCLS, the brightest X-ray source in the world,” said SLAC professor of photon science Siegfried Glenzer, who coauthored a paper recently published in Nature Astronomy. “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.”
Billions of miles away, diamonds form over 5,000 miles beneath the Neptunian and Uranian surface, then precipitate out and fall further into the atmosphere before raining down. The experiment offers new insight to planetary scientists who want to understand more about the atmosphere of these planets and exoplanets like them. Along with telescope and satellite observations, this experiment is as close as we can get to actually exploring these frozen orbs from the inside. Nanodiamonds could also have other applications in medicine and tech. Jewelry may be asking too much.
It may not rain diamonds on Earth anytime soon, but you will never look at a polystyrene cup the same way again.