Research led by a Kent-based space scientist has uncovered new evidence of meteor particles reaching the Antarctic ice sheet 430,000 years ago.
The findings highlight the importance of reassessing the threat of medium-sized asteroids, with the potential for “destructive” consequences, the team said.
Researchers recovered extra-terrestrial particles on the summit of Walnumfjellet within the Sor Rondane Mountains in east Antarctica.
The discovery indicated a so-called low-altitude meteoritic touchdown event – where a jet of melted and vaporised material from an asteroid at least 100 metres in size reached the surface at high velocity.
The impact covered a circular area of around 2,000km – an “almost-continental scale distribution”, said Dr Matthias van Ginneken from the University of Kent’s School of Physical Sciences.
The research, published in the Science Advances journal, said finding evidence of such events “remains critical to understanding the impact history of Earth and estimating hazardous effects of asteroid impacts”.
Dr van Ginneke said while it is “highly unlikely” that such an event would happen over a densely-populated area – with less than 1% of the surface of the earth considered densely populated – its effects can be widespread.
He said: “Severe effects of such an impact can be felt over hundreds of kilometres.
“Therefore, even if such an impact were to occur hundreds of kilometres away from a densely populated area, the amount of devastation would not be negligible and would need to be taken into account.”
Dr van Ginneken said the study could help improve knowledge of the rate of such impacts in the past and therefore how often these might happen in the future.
The paper states: “These events are potentially entirely destructive over a large area, corresponding to the area of interaction between the hot jet and the ground.
“Touchdown events may not threaten human activity, apart from the formation of a large plume and the injection of ice crystals and impact dust in the upper atmosphere, if these occur over Antarctica.
“However, if a touchdown impact event takes place above a densely-populated area, this would result in millions of casualties and severe damage over distances of up to hundreds of kilometres.”