Specks of leftover cosmic dust from the birth of the Solar System have been found on the rooftops of three European cities.
Remnants From The Formation Of The Solar System
Cosmic dust are particles that have existed since the birth of the Solar System. The tiny particles measuring just about 0.01 millimeters in size have been falling to our planet.
Scientists are interested in these ancient particles because analysis of their mineral and chemical content can yield clues about the evolution of the early Solar System.
Cosmic Dust In Urban Areas
Prior to the discovery, the space debris, which constantly falls through the atmosphere, has only been found in the deep ocean and Antarctica. It was previously thought that it could not be found in cities because the pollution, dust and grime in urban areas would make it difficult to find.
Many people have already reported finding the space dust in urban areas but these were found to be of industrial origin after scientists analyzed them.
Matthew Genge, from the Imperial College London, and colleagues, however, have confirmed that these particles have been discovered on the rooftops of three cities in Europe: Berlin, Oslo and Paris.
"The identification of particles as micrometeorites is achieved on the basis of their compositions, mineralogies, and textures," the scientists reported. "The reported particles are likely to have fallen on Earth in the past 6 yr and thus represent the youngest large micrometeorites collected to date."
Fastest Moving Dust Particles
In the new study published in the journal Geology, Genge and colleagues found that the cosmic dust particles that they found from city rooftops are bigger than the particles that have earlier been found.
On the basis of the size, the researchers think that these particles were formed by melting when they entered the atmosphere at a speed of about 12 kilometers per second, which would make them the fastest moving dust particles that have been discovered on Earth.
Because cosmic dust particles contain minerals that make them magnetic, researchers turned to magnetism to separate the particles under the microscope finding 500 in the debris.
The cosmic dust recovered in the urban area likewise contains fewer feather-like crystals compared with old cosmic dust found in Antarctica that accumulated in ice over the last million years. The urban cosmic dust is similar to those that fell on Earth during medieval times.
Genge said that the difference could be due from changes in planetary orbits in the Solar System. The resulting gravitational disturbances possibly influenced the trajectory of the particles as they traveled through space, which would also have affected the speed at which they slammed into the Earth's atmosphere.