Three European cities have discovered cosmic dust among their rooftops. The tiny particles from space have been dated back a staggering 4.6 billion years to the birth of the solar system.
Experts normally go to the frozen wastes of Antarctica to gather the space dust. Now for the first time, scientists have come across the cosmic debris mixed in city dirt.Researchers sifted through 300 kilogrammes of muck embedded in the roof gutters of buildings in Oslo, Berlin and Paris. By using magnets the team was able to extract particles containing magnetic minerals and were able to verify 500 cosmic dust grains.
Imperial College London’s Matthew Genge told New Scientist, “We’ve known since the 1940s that cosmic dust falls continuously through our atmosphere, but until now we’ve thought that it could not be detected among the millions of terrestrial dust particles, except in the most dust-free environments such as the Antarctic or deep oceans.”
It was a Norwegian amateur scientist, who contacted the Imperial College to suggest they begin looking in cities. Despite their initial scepticism, they discovered particles that were three times larger than previously discovered. “This find is important because if we are to look at fossil cosmic dust collected from ancient rocks to reconstruct a geological history of our solar system, then we need to understand how this dust is changed by the continuous pull of the planets,” Genge said.