Particles unearthed in Antarctica were produced when meteorite exploded in mid-air

An ancient meteorite that exploded in the air 430,000 years ago has left unusual particles of matter in the mountains of Antarctica, a new study reveals.

An international team of space scientists, led by the University of Kent, examined “alien particles” recovered from the top of Walnumfjellet Mountain in the Sør Rondane Mountains of Queen Maud Land, Antarctica.

The pieces of vaporized space rock were deposited after a 330-foot asteroid exploded near the frozen surface of Antarctica hundreds of thousands of years ago.

The results can help scientists identify past impacts of “air blasts” and prepare for future ones, which could cause severe destruction if they occur in densely populated places.

Large aerial explosions, which occur when asteroids enter Earth’s atmosphere and explode in the air, are estimated to occur much more frequently than crater-forming impacts.

However, due to the challenges of identifying and characterizing distant tailings from exploded meteorites, large aerial explosions are primarily identified by eyewitness testimony rather than evidence in the geological record.

To piece together the puzzle of a possible ancient meteorite event that struck Antarctica with barely a trace, the study’s authors looked at tiny particles.

Matthias Van Ginneken and his colleagues used microscopy and laser techniques to analyze 17 black spherical igneous particles collected at Walnumfjellet.

They determined that the particles, which were mostly between about 100 and 300 microns in size, were mostly composed of the minerals olivine and iron spinel, soldered together by small amounts of glass.

The chemistry of these particles, including their high nickel content, suggests that they originated in outer space.

They also compared the particles with those found in other ice cores, which record meteorite events over Antarctica 430,000 and 480,000 years ago.

The team observed similarities that suggest the particles resulted from an impact of a single asteroid about 430,000 years ago.

They used a combination of numerical simulations with the low content of oxygen-18 isotopes observed in the particles, to identify their origin.

Noting the absence of a crater related to the event, Ginneken concluded that the particles reached the ice cap through jets of projectile vapor released by the exploded meteorite, which was likely between 330 and 500 feet in diameter.

This type of explosion is described as intermediate, as it is larger than an aerial explosion, exploding at high altitudes, but smaller than an impact crater event.

The results indicate a much more dangerous impact than the events of Tunguska and Chelyabinsk on Russia in 1908 and 2013, respectively.

This research, published by Science Advances, guides an important discovery for the geological record where evidence of such events is scarce. .

The study highlights the importance of reassessing the threat from medium-sized asteroids, as it is likely that similar touchdown events will produce similar particles.

Such an event would be entirely destructive over a large area, corresponding to the area of ​​interaction between the hot jet and the ground, the team warned.

Ginneken said: “To complement the asteroid impact recording, we recommend that future studies focus on identifying similar events on different targets.”

These targets include rocky or shallow ocean subsoils, with the Antarctic ice sheet covering only 9% of the Earth’s land surface.

“Our research may also prove useful in identifying these events in deep seabed sediment cores and, if the expansion of the plume reaches landmasses, the sediment archives,” he added.

While landing events do not threaten human activity if they occur over Antarctica, if they were to occur over a densely populated area, it would result in millions of casualties and severe damage over hundreds of kilometers, they warned.

The results were published in the journal Science Advances.