Small particles taken from a mountain top in Antarctica are evidence that a meteorite nearly 100 meters wide exploded in the sky, shooting fireballs at the ice.
Such aerial explosions occur more often than the fall of asteroids or asteroids that create ground craters like dinosaur eradicators 66 million years ago. However, the identification of these meteorites is much more difficult because they leave very few traces in geological records.
“Asteroids have to be large enough to fly through the atmosphere and crash to the ground at a speed sufficient to form a crater. Smaller objects explode in the atmosphere and do not create craters,” said Mark Boslough, researcher at the University of New Mexico. .
Matthias van Ginneken, a researcher at the School of Physics at the University of Kent, collected 17 dark particles, all smaller than a millimeter and invisible to the naked eye, during an expedition to the Sør Rondane Mountains in the region. Land of Queen Maud in eastern Antarctica, where the Princess Elisabeth of Belgium research station is located.
“I noticed for the first time that some particles looked like they were before, which must have happened when they melted. This meant that many particles were interacting with each other at very high temperatures. Explain that it was a very strong impact, “said van Ginneken, head of the study, published March 31 in the journal Science Advances.
van Ginneken and international scientists were able to sequence what happened when ancient meteorites plunged into Earth’s atmosphere by analyzing microscopic particles. The nickel-rich composition shows that they originate from outer space. The team compared them to similar particles found in two ice cores, which served as a storage medium for geological conditions in the past. The specimen dates back to 430,000 years ago, taken from another location in eastern Antarctica. The numerical model considers the distribution and density of telltale asteroid particles about 100 to 150 m wide.
Although the meteorite did not create a crater, it still had a lot of impact on the ground. According to van Ginneken, it’s an impact when it lands, like an explosion in the atmosphere that creates a cloud of hot gas that travels very quickly towards the ground. van Ginneken surmised that if such an event occurred in a populated area, it would result in millions of deaths and serious injuries for hundreds of miles. For example, a meteor flew through Earth’s atmosphere over Chelyabinsk, Russia, in 2013. The object exploded in the air, creating a fireball brighter than the Sun. The meteors injured 1,000 people and destroyed more than 7,000 buildings. The shock wave of the explosion shattered the windows at a distance of 94 meters.