Cosmic Dust From Space Found On The Rooftops Of Cities For The First Time

The rooftops of three major cities including Paris, Oslo and Berlin are covered with cosmic dust from space. This was the first time cosmic dust has been seen in cities. It is usually found in the frozen wastes of Antarctica.

The researchers discovered about cosmic dust grains in roof gutters in Paris, Oslo and Berlin. They used magnets to pull out the particles that have magnetic minerals. These minute particles dated back to the birth of the solar system 4.6 billion years ago.

Matthew Genge from Imperial College London said that since the 1940s, the cosmic dust falls continuously through the atmosphere. But until now, they have thought that it could not be detected among the millions of terrestrial dust particles, except in the most dust-free environments such as the Antarctica or deep oceans. He further said that the obvious advantage to this new approach is that it is much easier to source cosmic dust particles if they are in the backyards.

Cosmic dust particles are about few molecules to 0.1 μm (micrometer) in size. The cosmic dust can be determined by its astronomical location, namely, interstellar dust, intergalactic dust, circumplanetary dust and interplanetary dust. The sources of solar system dust are asteroidal dust, comet dust, interstellar dust and dust from Kuiper belt.

Jon Larsen, a scientist from Norway, was the first to find the cosmic dust in the city and then he contacted Imperial. Genge said that when Jon first came to see him, he was dubious. This is because many people before who reported finding cosmic dust in urban areas were not cosmic dust but rather particles that were of industrial origin.

The cosmic dust that was found in the city was larger than the recovered particles before. It measured about 0.3 millimeters instead of the usual 0.01 millimeters. It also has fewer feather-like crystals than the much more ancient particles from Antarctica, according to New Scientist.

In the study, the team discovered that the cosmic dust entered the atmosphere at around 12 kilometers per second, which makes it the fastest moving dust particles ever found on Earth. Genge said that the discovery is significant because one look at fossil cosmic dust collected from ancient rocks can reconstruct a geological history of the solar system. He further said that they need to understand how this dust is changed by the continuous pull of the planets.