Scientists have found a grain of quasicrystal in the rubble of the first atomic bomb test conducted 76 years ago in the United States, a new study has announced. Researchers believe that this may be the first time in human history that this amazing material has been inadvertently synthesized.
A quasicrystal is a very special kind of crystal. Its interior has a symmetrical structure like a normal crystal, but it does not have a repetitive pattern, or translational symmetry. Scientists used to think that this substance did not exist until 1982, when Israeli materials scientist Dan Shechtman discovered its existence and won the Nobel Prize for it.
During World War II, as part of the Manhattan Project, the U.S. Army conducted a nuclear test code-named “Trinity” in the New Mexico desert on July 16, 1945. The test was seen as a symbol of the beginning of the nuclear age.
After the explosion, silicate sand was sucked up into the air by a large fireball from the blast, producing minerals called Trinitite that were then scattered from the sky to the ground.
Most of these minerals are green, but occasionally one or two pieces of red, the sand should be fused with the test recording equipment on the copper oxide reason. Until now, scientists were not clear exactly under what conditions the vitrinite would be produced. The site has been protected and the removal of any stones from the site constitutes a crime.
A recent study, done jointly by the University of Florence (Italy) and Princeton University (USA), found a quasi-crystal in the remains of these explosives, inside a sample of red glass stone only 1 cm long.
The researchers knew that a high-temperature, high-pressure environment was part of the conditions for generating quasicrystals, so the group wanted to investigate the debris from the Trinity nuclear test site.
Most of the quasicrystals were metal alloys. So the researchers isolated 12 metallic objects from the samples and analyzed them with X-ray diffraction techniques. It turned out that one of the metallic objects had not only a double axis of symmetry, but also triple and quintuple axes of symmetry, a feature that only quasicrystals have.
The researchers said that quasicrystals can only be produced under extreme conditions and environments, and it is unlikely that humans had such an environment to create quasicrystals before that, so this nuclear test should be the first time that humans inadvertently synthesized quasicrystals.
The first naturally occurring quasicrystal discovered by humans to date was found in 2010 inside a Khatyrka meteorite. Scientists believe the meteorite’s origin dates back as far as the early days of the solar system.
Chloe Bonamici, a chemist at the University of Wisconsin-Madison, said this suggests that the interior of a nuclear explosive fireball is a very unusual environment, capable of synthesizing exotic materials. Specifically, it is possible that the condensation process of vapor and plasma inside the nuclear explosion fireball plays an important role. Many synthetic quasicrystals now involve vapor deposition, plasma spraying and other similar processes.
Since this nuclear test site can produce quasicrystals, Bonamici said, it suggests that new quasicrystals will be found at other nuclear test sites, which will help us understand the various conditions required for their production in nature. “For now, this tiny quasicrystal is a tantalizing little mystery inside a much larger one.”
The study will be published June 1 in the Proceedings of the National Academy of Sciences (PNAS).
Recent Comments