“Forbidden” quasi-crystals were created by the world’s first atomic bomb explosion



Early on the morning of July 16, 1945, the world’s first atomic bomb explosion ravaged the dusty deserts of New Mexico, sending a mushroom cloud 11,500 meters (~ 38,000 feet) into the air. Amid the unspeakable destruction caused by the nuclear test, known as the Trinity, the explosion also created something quite remarkable: “forbidden” quasi-crystals that call into question what we know about. physics.

In a new study, published this week in the journal Proceedings of the National Academy of Sciences, an international team of scientists details the discovery of this type of unprecedented quasi-crystal.

“Until today, we knew that natural quasi-crystals formed under extreme conditions of temperature and pressure: the only two that have been documented, icosahedrite and decagonite, had been found, thanks to my studies. previous research, in fragments of a meteorite that fell in the Koryak Mountains. , in the far east of Russia, about 15,000 years ago, ”said Luca Bindi, lead author of the study and professor at the Department of Earth Sciences at the University of Florence, in a declaration.

“The conditions under which the two quasicrystals formed, probably during collisions between asteroids in space at the start of the solar system, are comparable to those produced during atomic explosions. This is why I decided to study the material formed in the Trinity test.

Image of a sample of red trinitite that contained the quasicrystal. Image credit: Luca Bindi and Paul J. Steinhardt.

The Trinity Bomb Test saw an atomic bomb explode on top of a 33-meter (100-foot) steel tower. Subjected to an unholy amount of thermal energy, the sand in the crater below was melted into a green (and sometimes red) glass-like material known as trinitite. Using a range of high-tech imaging techniques, the researchers examined some of the trinitite samples forged by the test. He revealed that the trinitite sample contained strange metallic spots consisting of an unknown icosahedral quasicrystal composition, Si61Cu30Ca7Fe2.

Quasi-crystals have already been found in meteorites and synthesized in the laboratory, but it is believed to be the earliest example of a man-made quasicrystalline by the explosion of an atomic bomb. The newly discovered quasi-crystal has quintuple, triple and double symmetries, a pattern that violates the rules of symmetry of normal crystals.

A typical crystal refers to a material whose atoms are ordered symmetrically in a periodic, repeating pattern. In quasicrystals, however, the atoms are always ordered but the pattern does not repeat. This results in a strange asymmetric, non-repeating atomic structure that is not seen in typical crystals and is known as “forbidden symmetry”. Daniel Shechtman, an Israeli materials scientist, first discovered quasicrystals in the 1980s. The work initially drew criticism and even outright mockery, but it eventually won him the Nobel Prize in Chemistry 2011. It is a way of silencing your enemies.

Correction 05/24/2021: This article originally stated that the bomb was dropped from the tower. It has since been altered to explain that it exploded at the top of the tower.


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