A group of researchers at the University of Kent, UK, discovered evidence about a meteorite that exploded in the Antarctic region 430,000 years ago.
Led by Professor Matthias van Ginneken, the scientists found the necessary evidence after collecting materials at the summit of Mount Walnumfjellet, which is in the Queen Maud Land region of eastern Antarctica.
According to the study, the asteroid up to 100 meters in diameter would have exploded in midair before coming into contact with the ground – something relatively common, but which leaves few traces. The event would have been “medium impact”, without any human presence, but probably scaring the local fauna.
Van Ginneken’s research involved analyzing the chemical composition of rocks found in the region, possibly resulting from the meteorite explosion.
The collected particles are between 100 and 300 micrometers and have a high amount of nickel, which is common in celestial bodies that fall to Earth, in addition to an oxygen isotope from the region, suggesting contact with the region’s ice. This mixture is not common neither to the native materials of the soil nor in asteroids that collide with the Earth, indicating that the sediment was formed by an explosion process in midair.
However, not all the answers have been found: it is not yet known why the asteroid exploded when it fell instead of leaving a crater in the ground. Such events happen when the stone, which is at a high temperature, had cracks in its composition, cannot withstand high pressure when entering the atmosphere and is vaporized. The wreckage spreads without major damage to the land.
This explosion phenomenon is considered a probable explanation for what happened in the Tunguska region, in Siberia, in 1908, when a meteor devastated the local forest.
The study’s conclusions still suggest that medium-sized impacts like this should be better studied, including to prepare the planet for possible falls of this type. Similar methodologies can also be applied to detect falls from asteroids in other parts of the planet as old as the one now recorded.
The full study can be read in the journal Science Advances.