Carbon crystals of unusual shape were found in the ‘Chelyabinsk meteorite’ | Sorae Portal site to space

On February 15, 2013, a meteorite passed over the Russian city of Chelyabinsk. The meteor became brighter than the sun even though it was daytime, and shock waves from the decomposition in the air shattered the windows of thousands of buildings and injured nearly 1,500 people. Then the meteor fell to the ground and is nowChelyabinsk meteorite“its name.

The catastrophe caused by the Chelyabinsk meteorite left its name as the first large-scale meteorite disaster to be reliably recorded. Celestial bodies are not called meteorites, but we will refer to them here as “meteorites” for clarity).

On Earth, various large and small fragments of the Chelyabinsk meteorite were found, but other unique materials were also collected.

The Chelyabinsk meteorite, which entered the atmosphere at a very high speed, is exposed to high temperature and pressure due to atmospheric pressure and friction. This causes the meteorite’s surface to evaporate and then rapidly cool into dust particles much smaller than 1 mm. The dust drifted in the atmosphere for a while and was observed as a meteor cloud for a while. The dust that created this meteor cloud is gradually falling to Earth.

This is in the fall of the Chelyabinsk meteoritegathers a lot of dustit has been. This is extremely rare, thanks to the huge amount of dust created by the Chelyabinsk meteorite, and the fact that it was winter and new snow fell.

Meteor dust is an outstanding material subject to very unusual environments. Materials on the surface of meteorites and in the atmosphere may show some type of chemical reaction or catalytic activity when exposed to high temperature and pressure. It is a difficult environment.Create conditions that are difficult to reproduce by human handsFalling meteorites are, so to speak, a laboratory of high temperature physicsAnd dust from the Chelyabinsk meteorite is a very rare opportunity to see it.

[▲ الشكل 2: الغبار من نيزك تشيليابينسك المحفوظ في طبقات بين الثلج المتراكم (مصدر الصورة: Taskaev، et.al.)]

A research team led by Sergei Taskayev from Chelyabinsk State University observed the dust of the Chelyabinsk meteorite, which provided a valuable opportunity. When we collected dust that was kept in layers among the stacked snow and observed the particles with an optical microscope, we found many tiny carbon crystals. Each of them is about several micrometers in size (1 micrometer = 1/1000 mm).

[▲ الشكل 3: بلورات الكربون الموجودة في الغبار من نيزك تشيليابينسك. لها أشكال غريبة مثل القضبان السداسية والمجالات متعددة السطوح (Credit: Taskaev، et.al.)]

For detailed observation, when imaging with a scanning electron microscope,Carbon crystals have distinct shapes such as polyhedrons near hexagonal spheres and bars.I understand. Raman spectroscopy and X-ray crystal structure analysis showed that these were graphite crystals.

Graphite is an allotrope of carbon commonly found in everyday life, like pencil filaments. However, the crystals tend to form hexagonal prismatic plates, and do not form tall rod-shaped crystals or polyhedral crystals like balls.

What is the origin of such a strange shape? Taskaev and colleagues simulated how carbon atoms are bound and how crystals unite and grow to form carbon crystals like those in dust (more precisely, the discrete Fourier transform and using the methods of classical and quantum molecular dynamics, we simulated the growth mechanism of the closed shell multiple carbon twins).

[▲الشكل4:نمومحاكىلبلوراتسداسيةشبيهةبالقضيبيُعتقدأنبلوراتمنهذاالشكلقدنمتمنلبمتعددالهيكساسيكلوكتاديكان(رصيدالصورة:Taskaev،وآخرون)】

[▲الشكل5:نمومحاكىلبلوراتكرويةمتعددةالسطوحيُعتقدأنبلوراتمنهذاالشكلقدنمتمننواةبوكمينسترفوليرين(رصيدالصورة:Taskaev،وآخرون)】

نتيجة لذلك ، تم تضييق اثنين من المرشحين الأقوياء وصولاً إلى المواد “النواة” التي تشكل بلورات الكربون الموجودة. واحد هو”بكمنستر الفوليرينوالآخر هو “متعدد الهيكساكلو أوكتاديكان“هو. تنمو بلورات الجرافيت حول هذه الجزيئات وتتشابك جيدًا مع بعضها البعض ، وتشكل بلورات طويلة على شكل قضيب مثل تلك الموجودة في الغبار والبلورات متعددة السطوح مثل الكرات.

مثل الفحم الذي تم دفنه في طبقات جيولوجية لمئات الملايين من السنين ، يمكن تخزين الكربون في الأرض لفترة زمنية طويلة إذا كانت الظروف مناسبة. بناءً على هذا الاكتشاف ، يفترض Taskaev وزملاؤه أن العثور على بلورات الكربون ذات الشكل الفريد قد يوفر أدلة لتقدير توقيت سقوط النيزك في الماضي.

مصدر

• سيرجي تاسكايف وآخرون. “البلورات الدقيقة الكربونية الغريبة في الغبار النيزكي لسوبربوليد تشيليابينسك: التحقيقات التجريبية والسيناريوهات النظرية لتكوينها”. (المجلة الفيزيائية الأوروبية بلس)
• الإعصار. TT. “ملف: أثر النيزك في Chelyabinsk.JPG”. (WikiMedia Commons)

النص: رير آية