For a long time, based on the analysis of lunar rocks and meteorites, scientists have been creating various models of the formation of the moon. However, to date, they manage to simulate only one-time copies, without displaying all the geological processes occurring on the Earth's satellite. To validate existing models, it is necessary to know the conditions under which the existing rock samples were formed.
“We are looking for a large enough analogue in order … to simulate the processes occurring on the moon during the era of planetary formation,” explained James Day, a geochemist at the University of California at San Diego.
Day and colleagues' findings were published on February 8 in a Science Advances article. To the scientific happiness of researchers, just a few decades ago, a nuclear bomb was tested, which dramatically changed the chemical composition of rocky rocks on Earth.
The explosion of a plutonium bomb, New Mexico, USA, 1945
The bomb tests were first carried out near Alamgordo, in the state of New Mexico, in the United States, in July 1945. When the dust settled after the explosion of this plutonium bomb, some of the reddish rocky rocks turned into light green glass. This glass has been called 'trinitite'.
“We can use trinitite glass (alamogord glass) from this hugely influential experiment with scientific benefit for all mankind,” Day said.
By studying trinitite, Day hoped to gain an understanding of how the material from which the moon was formed could have changed over time, taking into account the canonical model of the lunar formation. According to this already classical hypothesis, a “huge influence” on the formation of our satellite was provided by an object the size of Mars, which in the distant past collided with the Earth, throwing a huge amount of materials and rocks into space, from which the Moon was then formed in orbit.
How does this relate to the test of the atomic bomb? For Day, the answer is clear – exposure from a Mars-sized body, he believes, vaporized some of the volatile elements in the material that ultimately formed the moon. The same thing happened in the nuclear explosion, which created trinitite depleted in volatile elements.
Taking this theory as a basis, the researchers focused on such a volatile element as zinc. The idea was that the hot, high-pressure conditions of a nuclear explosion would mimic the conditions supposedly occurring in a large model of planetary collisions and cause evaporative fractionation. In other words, the lighter zinc isotope was posed as a prime candidate for vaporization in the explosion of relatively heavier isotopes. Imagine the surprise of scientists when they found that a similar fractionation of zinc was found in some lunar rocks:
“We were really struck by how close the trinitite glasses were to the lunar rocks,” Day said.
Sources: csmonitor
