Crystals unknown to Earth discovered in Chelyabinsk meteorite dust

On September 15, 2013, a meteorite 18 meters long and weighing approximately 11,000 tons, it crossed the skies of Russia before disintegrating at a height of 23 kilometers over the city of Chelyabinsk, in the south of the country. The very powerful shockwave caused a lot of damage, exploding the Caractéristiques de la vitre
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buildings in the region. L’Energy released during this explosion was estimated to be 30 times the power of the Hiroshima bomb. Therefore, it is the largest known event of its kind since the fall of the object above. Il fut établi par la suite qu’un astéroïde mesurant entre 30 et 40…” data-image=”” data-url=”” data-more=”Lire la suite”>Tunguska (Siberia) in 1908, including the explosion in theatmosphere it had devastated a forest in a radius of 20 kilometers.

In both cases, the disintegration of the meteorite aloft avoided a collision with the earth’s surface that would surely have resulted in a much more dramatic catastrophe, reminding humanity that we are continually exposed to these types of risks to the environment at unpredictable times.

A large column of meteorite dust

The entry into the atmosphere of the so-called Chelyabinsk meteorite, and in particular its explosion, has been widely documented by numerous amateur videos, which have allowed scientists to reconstruct the trajectory of the meteorite and define its characteristics.

But to study it more precisely., nothing better than finding fragments. But this is not so obvious. When a meteorite enters the Earth’s atmosphere, the heating it experiences usually leaves behind a small amount of dust. The meteor usually ends up “burning up” almost completely before hitting the ground. It is often very difficult to find this very fine powder spread over the landscape of a large area.

However, in the case of the Chelyabinsk meteorite, the relatively large size of the race car it produced a large plume of dust that remained suspended in the atmosphere for several days, allowing for easier collection of these tiny particles. Much larger fragments were also discovered in the following months. A piece of about 570 kg. it was thus taken from the bottom of Lake Chebarkul. Analysis of these residues showed that it was a ordinary chondrite (rocky meteorite).

Rare and exotic graphite crystals

But it was by analyzing the tiny specks of dust that Russian scientists made a fortuitous and surprising discovery. Under’eye of microscopea new type of glass has actually been observed. Very small in size, a few micrometers it’s just that these crystals come in two distinct shapes hitherto unknown on Earth: some are almost spherical in shape, and others are in the shape of a hexagonal bar. X-ray analysis reveals that they are, in fact, crystals of graphite, one of the crystalline forms of graphite. Généralités
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the same one that is still commonly used in our pencils.

But these crystals have an additional feature. They contain at their center a carbon nanostructure that could be a buckminsterfullerene, a spherical molecule made up of 60 carbon atoms and shaped like a Chimie : un ballon pour chauffer le milieu réactionnel
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football (hence his nickname footballer). This nanostructure could also be polyhexacyclooctadecane, a molecule composed of carbon andGénéralités
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A specificity of the Chelyabinsk meteorite?

The very exotic architecture of these crystals suggests that they formed under conditions of high temperature and high Pressure, which could correspond to the moment of the fragmentation of the meteorite in the Earth’s atmosphere. However, the exact mechanism of its formation remains to be elucidated. These results were published in the journal The European Physical Journal More.

The next step now is to find out whether these crystals are specific to the Chelyabinsk meteorite or not, by looking for their traces in dust samples from other meteorites.

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