Crystals unknown to Earth discovered in dust from the Chelyabinsk meteorite

On September 15, 2013, a meteor 18 meters long and weighing approximately 11,000 tons passed through the skies of Russia before breaking down at an altitude of 23 kilometers above the city of Chelyabinsk, in the south of the country. The very strong shock wave caused a lot of damage, the exploded window and Windows buildings in the region. L ‘strength released during this explosion was actually estimated to be 30 times the power of the Hiroshima bomb. This is the largest known event of this kind since the fall of the object on top Tunguska (Siberia) in 1908, including the eruption ofatmosphere destroyed a forest within a radius of 20 kilometers.

In both cases, the meteorite disintegration at altitude avoided a collision with the Earth’s surface that would inevitably result in an even more serious disaster, reminding humanity that we are constantly exposed to this kind of danger for the environment. .

A large plume of meteoritic dust

The entry into the atmosphere of the so-called Chelyabinsk meteorite, and especially its eruption, has been widely documented in numerous amateur videos, enabling scientists to reconstruct the meteorite’s path and determine its characteristics.

But to study it more accurately, there is nothing better than finding the pieces. But this is not very clear. When a meteorite enters the Earth’s atmosphere, the heating it experiences will usually leave a small amount of dust. The meteorite usually ends up “burning” almost completely before hitting the ground. It is often very difficult to find this very fine dust sprayed on the landscape in a large area.

However, in the case of the Chelyabinsk meteorite, the relatively large size of racing car produces large plumes of dust that remain suspended in the atmosphere for several days, making it easier to collect these small particles. Several large fragments were also discovered in the following months. A piece of about 570 kg thus carried from the bottom of Lake Chebarkul. Analysis of these remains shows that it is a ordinary chondrite (meteorite rock).

Strange and exotic graphite crystals

But by analyzing the small fragments of dust the Russian scientists have made a strange and surprising discovery. Ilalum ‘eye from MICROSCOPEa new class of crystal really observed. Very small in size, few micrometer only, these crystals come in two distinct shapes not yet known on Earth: some have an almost circular shape and some have the shape of a hexagonal rod. X-ray examination revealed that they were in fact crystals of graphite, one of the crystal forms of carbonthe same is still commonly used in our pencils.

But these crystals have an extra side. They form at their center a carbon nanostructure that becomes a buckminsterfullerene, a spherical molecule composed of 60 carbon atoms and it takes the form of a ball football (hence his nickname of football player). This nanostructure can also be polyhexacyclooctadecane, a molecule composed of carbon andhydrogen.

A Chelyabinsk meteorite specific?

The very unique architecture of these crystals suggests that they were formed under conditions of high temperature and high pressure, which would be equivalent to the moment of division of the meteorite in the Earth’s atmosphere. However, the exact mechanism of their formation remains to be elucidated. These results were published in the journal The European Physical Journal More.

The next step is now to determine whether these crystals are specific to the Chelyabinsk meteorite or not, by finding their traces of dust samples from other meteorites.

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