Particles unearthed in the mountains of Antarctica were produced when a meteorite EXPLODED in mid-air 430,000 years ago, study finds

• Researchers found evidence of extra terrestrial meteorite particles in Antarctica
• They are evidence of a meteor that exploded just above the surface of the Earth
• A near touchdown event over a populated area could prove destructive and fatalAn ancient meteorite that exploded in mid-air 430,000 years ago left behind 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 'extra-terrestrial particles' recovered from the summit of mountain Walnumfjellet in the Sør Rondane Mountains of Queen Maud Land, Antarctica.

  The pieces of vaporised space rock were deposited after a 330ft asteroid exploded close to the frozen surface of Antarctica hundreds of thousands of years ago.The findings may help scientists identify past 'airburst' impacts and prepare for future ones, which could wreak severe destruction if they happened in densely populated locations.  

  

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

  IMPACT EVENT: SPACE ROCK EXPLOSIONS RELEASING IMMENSE ENERGY 

  An impact event is when a space rock collides with the Earth, or explodes in its upper or lower atmosphere. 

  There can be significant consequences from a crater forming impact. 

  Including the Chicxulub event 66 million years ago that killed dinosaurs.

  The Tunguska event was a massive explosion in Russia in 1908 over a sparsely populated area of Siberia.

  It flattened 80 million trees, but left behind no impact crater. 

  It is thought it disintegrated six miles above the surface.  Large airbursts, which occur when asteroids enter Earth's atmosphere and explode in mid-air, are estimated to occur far more frequently than crater-forming impacts.

  However, due to the challenges of identifying and characterising the far-flung residues of exploded meteorites, large airbursts are mostly identified through eyewitness accounts rather than by evidence in the geological record.  

  To piece together the puzzle of a possible ancient meteorite event that struck Antarctica while barely leaving a trace, study authors looked to tiny particles.

  Matthias Van Ginneken and colleagues used microscopy and laser techniques to analyse 17 black, spherical igneous particles gathered from Walnumfjellet. 

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

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

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

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

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  An international team of space scientists, led by the University of Kent, examined 'extra-terrestrial particles' recovered from the summit of mountain Walnumfjellet in the Sør Rondane Mountains of Queen Maud Land, Antarctica

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

  Noting the lack of a crater tied to the event, Ginneken concluded that the particles reached the ice sheet through projectile vapour jets released by the exploded meteorite, which was likely between 330ft and 500ft in diameter.

  This type of explosion is described as intermediate, as it is larger than an airburst, exploding at high altitude, but smaller than an impact cratering event. 

  

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  The particles of vaporised space rock resulted from the atmospheric entry of an asteroid at least 330ft in size exploding near the surface at high velocity

  CHELYABINSK EVENT: THE LARGEST METEOR STRIKE IN A CENTURY

  A meteor that blazed across southern Ural Mountain range in February 2013 was the largest recorded meteor strike in more than a century, after the Tunguska event of 1908.

  More than 1,600 people were injured by the shock wave from the explosion, estimated to be as strong as 20 Hiroshima atomic bombs, as it landed near the city of Chelyabinsk.

  The fireball measuring 18 meters across, screamed into Earth's atmosphere at 41,600 mph. 

  Much of the meteor landed in a local lake called Chebarkul. The findings indicate an impact much more hazardous than the Tunguska and Chelyabinsk events over 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 in scarce. .

  The study highlights the importance of reassessing the threat of 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 complete asteroid impact record, we recommend that future studies should focus on the identification of similar events on different targets.'

  These targets include rocky or shallow oceanic basements, as the Antarctic ice sheet only covers nine per cent of Earth's land surface. 

  '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,' he added.

  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 hundreds of miles, they warned.  

  The findings have been published in the journal Science Advances. 

  Explained: The difference between an asteroid, meteorite and other space rocks

  An asteroid is a large chunk of rock left over from collisions or the early solar system. Most are located between Mars and Jupiter in the Main Belt.

  A comet is a rock covered in ice, methane and other compounds. Their orbits take them much further out of the solar system.

  A meteor is what astronomers call a flash of light in the atmosphere when debris burns up.

  This debris itself is known as a meteoroid. Most are so small they are vapourised in the atmosphere.

  If any of this meteoroid makes it to Earth, it is called a meteorite.

  Meteors, meteoroids and meteorites normally originate from asteroids and comets.

  For example, if Earth passes through the tail of a comet, much of the debris burns up in the atmosphere, forming a meteor shower.