Found: Crystal of the rain from the atomic bombing of Hiroshima


A sample of the particles discovered on the beaches of the Japanese peninsula of Motoujina.
A sample of the particles discovered on the beaches of the Motoujina Peninsula in Japan. Anthropocene, volume 25, March 2019, DOI: 10.1016 / j.ancene.2019.100196 / Used with permission

The atomic bombing of the US military. of Hiroshima, on August 6, 1945, "was the worst event ever made by man," according to geologist Mario Wannier. "You have a city, and a minute later you have no city." At least 70,000 people died because of the initial impact; The final death toll, which represents radiation, could exceed 145,000. Wannier and his colleagues recently found small remnants of this mbadive event on the beaches of the Motoujina Peninsula in Japan. These glbad particles were formed from the explosion and have resided in nearby beaches since then. They published their findings this week in the magazine. Anthropocene.

Wannier had been studying waste from beaches in different areas to compare the health of different marine ecosystems, when some particles from the Motoujina peninsula considered it unusual. Together with the particles generated by plants or animals, these were "aerodynamic, vitreous, rounded": they reminded him of what he had seen in sediment samples from the Cretaceous-Paleogene (K-Pg) boundary, the geological marker of mbad extinction that He cleared the dinosaurs about 66 million years ago. The research suggests that the mbad extinction was caused by the impact of a meteorite, which would have expelled materials from the soil into the atmosphere that descended like glbad.

The atomic cloud over Hiroshima.
The atomic cloud over Hiroshima. George R. Caron / Public domain

But these particles from the Motoujina peninsula were also remarkably different in various aspects of the K-Pg particles: some were rubbery, others had multi-layered glbad layers. The variety reflected the wide range of materials present in the particles, identified with an electron microscope at the University of California, Berkeley. That range is just an indication that the particles formed as a result of the Hiroshima bombing. An urban center presents a wider variety of materials, such as concrete, marble, stainless steel and rubber, than a test site in the desert like Trinity, in New Mexico, where the first nuclear explosion was tested. The particles resulting from that test, called trinitites, are noticeably less diverse in composition than what Wannier and his colleagues now call "Hiroshimaitas." The presence of crystals of anorthite and mullite in the particles, meanwhile, suggested that they had formed at temperatures hotter than 3,300 degrees Fahrenheit, or 1,800 degrees Celsius.

While this can not capture the scale of the destruction, the researchers estimate there are between 2,200 and 3,100 metric tons of particles per square kilometer of the beach area (if the sand is measured from the surface up to four inches below). Wannier says that this is the first time that they have been studied in detail since the bombing took place almost 75 years ago.

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