Invisible asteroids and other cosmic bodies made of a new form of matter may pose a threat to Earth, according to an Australian physicist.

Robert Foot of the University of Melbourne claims that a meteorite composed of mirror matter, which is an invisible dark matter that is said to make up over 95 percent of the universe, could impact the Earth without leaving behind any fragments.

An asteroid made up of mirror matter may have been responsible for the Tunguska blast, which destroyed acres of Siberian forest in 1908. Scientists have attributed the mysterious destruction to a meteor impact, but no traces of a meteor have ever been found.
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