More than 80 years after the world-famous Trinity test showed humanity what to expect from an atomic detonation, researchers are still sifting new discoveries out of its twisted remains.
An analysis conducted on material left from the famous experiment has revealed a cage-like crystal structure known as a clathrate, representing the first example of such a material being formed under the forces generated by a nuclear explosion.
On July 16, 1945, a plutonium bomb was detonated in the New Mexico desert as part of the Manhattan Project. The blast released an energy equivalent to about 21 kilotons of TNT, vaporizing rock and metal support structures at ground zero, and swept up vast quantities of the surrounding desert sand, blending it all together into a spectacularly violent atomic cocktail.
Under extraordinary heat and intense pressure of tens of thousands of atmospheres, this mist of molten sand, clay, metals from the 30 m (100-foot) high test tower, and copper wiring, fused and cooled to form a glassy material dubbed trinitite.
Much like its mythical cousin, kryptonite, trinitite comes in different forms – a common green variety, and a red form containing higher quantities of metals from the mix of copper cabling and framing surrounding the bomb.
Once a popular souvenir collected by tourists visiting the historic site, trinitite is now attracting attention from researchers keen to better understand the kinds of unique chemistry that take place under immense forces.
In 2021, a study led by University of Florence geologist Luca Bindi identified a new kind of icosahedral quasicrystal in samples of red trinitite.
Using a combination of X-ray diffraction and electron microprobe analyses, Bindi and his colleagues have now found yet another new material in copper-rich droplets of red trinitite, one found in close association with their previous discovery.
"We report the discovery of a previously unknown [calcium, copper, silicon] type-I clathrate formed during the Trinity nuclear test, representing the first crystallographically confirmed occurrence of a clathrate among the solid products of a nuclear detonation,” Bindi and his team write in their recently published report.
Clathrate compounds are found throughout nature, commonly trapping other materials in their cage-like structures. While they differ in arrangement from their non-repetitive cousins, the quasicrystal, similarities in the composition of the two trinitite materials made the researchers wonder whether they might share a deeper structural relationship.
“As both the clathrate and the quasicrystal are made of typical elements found in either desert sand or the metallic tower, it seems evident that both were formed in the detonation,” the researchers write.
Computer models based on the composition of ingredients suggested the clathrate would only have been stable at copper concentrations of around 10 percent, far lower than the 21 percent found in the trinitite. In other words, the cage-like crystals would have formed in the blink of an eye that it took for temperatures and pressures to rise and then fall.
“These findings rule out a simple clathrate-based structural interpretation for the Trinity quasicrystal and emphasize the distinct nature of silicon-rich phases generated under extreme conditions,” the researchers state.
It’s a set of conditions that we can only hope we never see again, making Trinity’s legacy of glassy rocks a rare example of creation amid a moment of pure destruction.
This research was published in the Proceedings of the National Academy of Sciences.
Fact-checked by Loz Blain
