The team analyzed 17 dark, rounded particles, which measure no more than half a millimeter. Through electron microscopy, Ginneken and the team discovered that these are condensation spheres, composed of iron, olivine and high amounts of nickel, whose composition corresponds to a type of meteorite known as “palasite”, which confirms that they came of space. In addition, there was little difference in the presence of oxygen isotopes in them when compared to spherules from other regions of Antarctica. In practice, this means that all the spherules formed in one event.
The explosion of this space rock was described by scientists as intermediate, because, although powerful, it was not intense enough to create a crater with the impact. However, the impact was far more intense than some events that occurred on Earth recently: the Tunguska event, which took place in Siberia in 1908, was so powerful that it destroyed more than 80 million trees in a matter of seconds – and the strangest thing is that there was no impact crater left behind.
In 2013, a meteorite hit the Ural Mountains region in Russia, and the fireball explosion was so intense that it hurt at least 400 residents, in addition to shaking buildings and blowing out window glass. According to the researchers involved in the work, this study is an important discovery for geological records, since the evidence of this type of events is quite rare because it is difficult to identify and characterize impact particles. The authors emphasize the importance of studies on the threat of medium-sized asteroids, which can produce particles of the same type.
If an object of this type reached Earth today, a large area could be destroyed: “to complete the record of asteroid impacts, we recommend that future studies be focused on identifying similar events from different objects, such as the ocean floor”, he explains Dr van Ginneken.
Although there is a possibility that such impacts will not threaten humanity if they occur in Antarctica, the scenario changes completely if the impact occurs elsewhere: “this changes if they occur in areas of high population density, with millions of casualties and some damage over distances a few hundred kilometers ”, he concludes.
The article with the results of the study was published in the journal Science Advances.
Fonte: University of Kent
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