‘Unseen before’ crystals found in dust left behind by largest meteoroid of the 21st century

“Unseen before” crystals have been found in tiny fragments of cosmic dust left behind by Chelyabinsk, the biggest meteor of the 21st century that exploded over Russia in 2013.

Crystals have been found in a variety of shapes, including hexagonal rods and closed quasi-spherical shells.

Analysis of the crystals by researchers from Chelyabinsk State University, Russia, showed that they are formed from layers of graphene or pure crystalline carbon.

Beneath the layers, they found two separate nanoclusters — a football-shaped fullerene molecule made of carbon, and a complex honeycomb structure of carbon and hydrogen.

It is hoped that the classification of these crystals will help scientists identify past meteorites.

A: Carbon crystal in the dust of the Chelyabinsk superbolide, visualized with an optical microscope. BD: Scanning electron microscope images of carbon crystals.

Left: A layer of meteoritic dust in the snow.  Right: SEM image of the filtered insoluble dust fraction separated for analysis.

Left: A layer of meteoritic dust in the snow. Right: SEM image of the filtered insoluble dust fraction separated for analysis.

Image of a reduced carbon particle bonded to epoxy before X-ray crystallography

Image of a reduced carbon particle bonded to epoxy before X-ray crystallography

Chelyabinsk meteorite (pictured) that exploded over Russia in 2013

Chelyabinsk meteorite (pictured) that exploded over Russia in 2013

WHAT IS THE CHELYABINSK METEOR?

The meteor that swept over the southern Urals in February 2013 was the largest recorded meteor strike in more than a century.

More than 1,600 people were injured by the blast, estimated to be as powerful as 20 atomic bombs dropped on Hiroshima, that landed near the Russian city of Chelyabinsk.

A fireball 60 feet (19 meters) in diameter crashed into the Earth’s atmosphere at a speed of 41,600 miles per hour. Most of the meteorite fell into a local lake called Chebarkul.

Since the February 15 incident, scientists have already found more than 12 pieces in Chebarkul Lake. However, only five of them turned out to be real meteorites.

The largest meteor observed so far this century entered Earth’s atmosphere over Chelyabinsk in the Southern Urals, Russia on February 15, 2013 at approximately 03:20 BST (09:20 YEKT).

This was due to the fact that a piece of space rock about 66 feet (20 m) high entered the atmosphere at a slight angle at a speed of about 41,600 miles per hour (66,950 km/h).

The light from the meteor was briefly brighter than the Sun, and some bystanders also felt intense heat from the fireball.

It exploded in a meteoric airburst, known as a superbolide, about 14.5 miles over Russia and spawned a cloud of hot ash and dust, as well as meteorite fragments.

More than 1,600 people were injured by the blast, estimated to be as powerful as 20 atomic bombs dropped on Hiroshima.

Meteoritic dust forms on the surface of a meteor when it is subjected to high temperatures and high pressure as it enters the atmosphere.

Usually, these tiny grains are lost because they are either too small to find, or are scattered by the wind, fall into the water, or are polluted by the environment.

Unusually, dust from the surface of the Chelyabinsk meteorite survived the fall to Earth because it landed on snow-covered ground, which helped preserve it.

A consortium led by Russian scientists Sergey Taskaev and Vladimir Khovailo analyzed the dust, the results of which were published last month in EPZh Plus.

First, they analyzed the dust under a light microscope, where they found micrometer-sized carbon crystals.

They then analyzed these crystals using scanning electron microscopy, which visualizes objects at higher resolution.

The researchers saw that they were formed from a variety of unusual shapes, including some closed, almost spherical shells and hexagonal rods.

In the article, they described it as “unique morphological features”.

Initial results of molecular shape dynamics of two crystals found in meteorite dust.  A: Buckminster fullerene, B: polyhexacyclooctadecane

Initial results of molecular shape dynamics of two crystals found in meteorite dust. A: Buckminster fullerene, B: polyhexacyclooctadecane

They then further visualized the crystals using Raman spectroscopy and X-ray crystallography.

Raman spectroscopy analyzes molecular vibrations, while X-ray crystallography creates an image of a molecule by the way it refracts an X-ray.

The results suggest that these unusual crystals were made from sheets of graphene – single layers of carbon atoms arranged in a hexagonal lattice – surrounding a central nanocluster.

The scientists then used computer simulations to investigate this stacking process and found two “likely suspects” in the contained nanoclusters.

The first is buckminsterfullerene, a molecule made up of 60 carbon atoms arranged in hexagonal shapes like a soccer ball.

The second is polyhexacyclooctadecane, C18H12, a complex molecule of carbon and hydrogen in a honeycomb structure.

It is hoped that future analyzes of dust from other meteorites will reveal whether these crystals are common meteor decay by-products or unique to the Chelyabinsk event.

Explanation: difference between asteroid, meteorite and other space rocks

An asteroid is a large piece of rock left over from collisions or the early solar system. Most of them are located between Mars and Jupiter in the Main Belt.

BUT comet rock covered with ice, methane and other compounds. Their orbits take them much farther from the solar system.

BUT meteor this is what astronomers call a flash of light in the atmosphere as debris burns up.

This rubbish is known as meteoroid. Most of them are so small that they evaporate in the atmosphere.

If any of these meteoroids reach the Earth, it is called meteorite.

Meteors, meteoroids and meteorites are usually formed from asteroids and comets.

For example, if the Earth passes through the tail of a comet, most of the debris burns up in the atmosphere, forming a meteor shower.