In February , van Ginneken visited Antarctica—a dream trip for him—in search of cosmic breadcrumbs. As a Ph. When he arrived with the Belgian Antarctic Meteorite expedition , it was the end of the field season and they had just two weeks to scour the landscape for microscopic extraterrestrial confetti. Scraped clean by glaciers more than , years ago, the summit site perfectly preserved cosmic debris. He and his colleagues collected more than 12 pounds of sediment from the summit and took it back to the lab.
Ultimately, they selected 17 spherules, tiny round grains of melted meteorite that are forged during impacts, for detailed scrutiny. Those ratios suggested that the spherules formed in direct contact with the Antarctic ice, which is unusual for an airburst.
The spherules closely resembled extraterrestrial dust that van Ginneken had studied before—grains embedded in immense ice cores retrieved from the nearby Japanese Antarctic station at Dome Fuji and from the French-Italian station at Dome Concordia on the other side of the continent.
Those grains are roughly , years old, an age that scientists can calculate based on their position in the ice cores—buried 1. Because of the similarities between the samples, the team reasoned that the grains were all formed during the same event.
Given the lack of craters in Antarctica, plus the spherules scattered across the continent, they suspected some kind of mega-Chelyabinsk-like airburst occurred in the distant past. So Natalia Artemieva , from the Planetary Science Institute, used computer simulations to test whether a more complex type of airburst might have occurred.
Boslough suspects that one of these events is the culprit behind mysterious, million-year-old glass scattered across the Eastern Sahara —smooth, yellow fragments resembling sea glass that have puzzled scientists because of their otherwise unexplainable presence in the middle of the desert.
Touchdowns can pack a deadly punch, obliterating whatever is beneath them. The new research, however, could provide a way to detect other touchdowns in the geologic record, allowing scientists to gain a better understanding of the threat these events pose to Earth.
The trouble starts, he says, with pinning an age on the spherules, which is extremely hard to do. With each new meteorite collected and studied, scientists answer and ask new questions about the early stages of our solar system. You can find her at erinmalsbury. Smithsonian Voices From the Smithsonian Museums. A meteorite in the process of being recovered by volunteers in the Antarctic Search for Meteorites program. The shiny fusion crust on this meteorite suggests it may be an achondrite.
ANSMET In mid-January of , a group of men lugged hundreds of pounds of supplies through fierce Antarctic winds, biting cold and dangerous crevasses for over a thousand miles. Why Antarctica? Gaelen Marsden The team also faces psychological challenges. The meteorites stay inside a nitrogen-filled container, even while scientists work with them.
Land-mine detectors also dislike being moved too rapidly, which is problematic for the team: Researchers have to be able to detect iron meteorites in real time while they zip about. Tests in Svalbard, a series of islands in the high Arctic, revealed other quirks; the detectors, for example, experience different types of signal noise on snow compared with ice.
The alternative to all this, though, would be exploring the continent by foot, using traditional metal detectors, a torturously slow endeavor. Already, though, researchers have some promising signs that their models and experiments are correct. Bits of mountain rock have been found falling into Antarctic ice and melting through, and Joy says that some meteorites they found have been partially buried within the ice, too. In both cases, heating during the austral summer days likely drove the rocks downward.
It is nevertheless prepared for the possibility that it ultimately ends up empty-handed. They could, of course, end up finding plenty, and that hypothetical buried treasure would suddenly become very tangible.
To show that iron meteorites might be found lurking beneath the surface, and to demonstrate that the model they have spent years working on applies to the real world, all they need to do is get lucky once. Just one. Skip to content Site Navigation The Atlantic. Our research may also prove useful for the identification of these events in deep sea sediment cores and, if plume expansion reaches landmasses, the sedimentary record. Caroline Brogan Communications Division.
Antarctica asteroid impact from , years ago discovered by scientists by Caroline Brogan 31 March Mark Garlick markgarlick. Faculty of Engineering.
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