Rocks have continued to fall out of the sky in a variety of sizes. And sometimes, they explode in the atmosphere instead of hitting. This happened over Tunguska Siberia in 1908, over Chelyabinsk Russia in 2013, and has probably happened many other times over places that had fewer humans to notice. One of those times appears to have been about 430,000 years ago over modern-day Antarctica.
Researchers exploring the summit of Walnumfjellet within the Sør Rondane Mountains in East Antarctica found myriad small weird nodules that appear to have come from an object bigger than your typical airburst but that didn’t crater the planet. This research is published in Science Advances with lead author Mattias van Ginneken and shows that medium-sized asteroids can be dangerous in a new way: they can literally explode like a massive cloud of tiny rocks in what are being called touchdown events. According to van Ginneken: While touchdown events may not threaten human activity if occurring over Antarctica, if it was to take place above a densely populated area, it would result in millions of casualties and severe damages over distances of up to hundreds of kilometers.
This is a reminder, space will try and kill us, and we’re still discovering all its weapons.
University of Kent press release
“A large meteoritic event over Antarctica ca. 430 ka ago inferred from chondritic spherules from the Sør Rondane Mountains,” M. Van Ginneken et al., 2021 March 31, Science Advances