Scientists use powerful laser shock waves to create tiny diamonds. Image Credit: Shutterstocktonkid

Blasting plastic with a powerful laser can produce tiny diamonds. Similar processes could occur in the high-temperature, high-pressure environments of planetary interiors, which could help explain why Uranus and Neptune are so bizarre.

Previously, researchers have been able to create nanodiamonds by lasing a mixture of carbon and hydrogen, but this requires extremely high pressure. Siegfried Glenzer and colleagues at the SLAC National Accelerator Laboratory in California, USA, found that by using a simple plastic called PET that contains carbon, hydrogen and oxygen -- often used to make bottles and other containers, they can make it easier to use under less extreme conditions. make diamonds.

Relevant research results were published in Science Advances on September 2.

When the researchers fired a powerful laser at the plastic, it was heated to between 3,200°C and 5,800°C, and the shock waves generated by the laser pulses raised the plastic's pressure to 72 gigapascals—equivalent to one-fifth of the pressure in the Earth's core. This separates the hydrogen and oxygen from the carbon, leaving only tiny diamonds a few nanometers in diameter and a type of water called superionic water, which conducts electricity more easily than regular water.

The process occurs at lower pressures than previous experiments using other materials, and like PET, the giant planet's interior contains oxygen, carbon and hydrogen, Glenzer said.

"That means diamonds could be everywhere," Glenzer said. "If it happens at a lower pressure than before, it means that this process could also occur in the interior of some moons like Uranus, Neptune and Titan. Because these celestial bodies contain hydrocarbons."

These diamonds formed in Neptune's mantle and then sank toward the core, creating friction and heat in the process, which could explain why the planet is unusually hot. And inside Uranus, superionic water left over from diamond formation may be conducting electrical currents, possibly related to the strange shape of its magnetic field.

In the next step, the researchers will collect the nanodiamonds after they have formed, Glenzer said. Similar materials are already used in industrial grinding processes for many scientific applications, but usually by detonating explosives.

"In other experiments, the necessary pressure was much higher, and the conditions were so extreme that the diamond would eventually disintegrate," Glenzer said. "Now that we have found a way to produce diamonds at lower pressures, there may be an opportunity. A real diamond harvest."

Related paper information:

https://doi.org/10.1126/sciadv.abo0617

(Original title "Scientists successfully turn plastic into diamonds")