Scientists have found traces of cosmic dust lying on the rooftops of buildings in Paris, Oslo, and Berlin – and it's the first time researchers have confirmed the discovery of these tiny particles in urban environments.
Cosmic dust is the name for small amounts of matter in space, including those left over from the formation of our Solar System some 4.6 billion years ago, and new research shows that these micrometeorites are still falling on Earth billions of years later.
"We've known since the 1940s that cosmic dust falls continuously through our atmosphere," says planetary scientist Matthew Genge from Imperial College London in the UK.
"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."
http://www.sciencealert.com/cosmic-dust-has-been-discovered-on-city-rooftops-for-the-first-time