2024 – Formation of Organic Compounds Through Meteoritic Atmospheric Shock

Formation of Organic Compounds Through Meteoritic Atmospheric Shock

2024 Research Campaign, Frontier Science

Purpose of Experiment

It is widely accepted that life on Earth started to form during the Archean period of the Earth’s history when the surface was mostly water, and the atmosphere was rich in methane but lacking free oxygen. It is not clear how organic molecules – the building blocks of life – initially formed in this oxygen-poor atmosphere. It is conjectured that the process could have been aided by plasma-meteoroid interaction during atmospheric entries as early as the Late Hadean period, which precedes the Archean. This project aims to investigate the formation of organic and complex inorganic molecules in a laboratory plasma environment by conducting experiments at the DIII-D National Fusion Facility.

The objective of these experiments is to test the hypothesis that organics and/or their complex inorganic precursors could have formed in the plasma tails of meteorites during entries into the Early Earth’s atmosphere. We expect that the interaction of compounds disassociated from the meteorite and compounds already present in the atmosphere will be enabled by the activation energy in the plasma environment. Using principles of physics, chemistry, and geology, our team plans to study the production of the organic compound urea and its inorganic precursor ammonia in controlled laboratory conditions.

Experimental Approach

We plan to utilize the DIII-D tokamak, where material samples can be exposed to plasma as hot and as dense as the plasma surrounding meteorites during atmospheric entries. In one set of experiments, powder samples will be injected into the plasma, while in another set of experiments, stationary rods will be exposed to the plasma and then retrieved for postmortem chemical analysis. To mimic meteoritic composition, the samples will be made of carbon (𝐢𝐢) and silica (𝑆𝑆𝑆𝑆𝑂𝑂2). Simultaneously, different gases will be puffed near the samples to simulate the atmospheric composition of different stages in the Earth’s history. The gasses puffed will be pure nitrogen (𝑁𝑁2), nitrogen-hydrogen (𝑁𝑁2 βˆ’ 𝐻𝐻2), and nitrogen-methane (𝑁𝑁2 βˆ’ 𝐢𝐢𝐻𝐻4) gas mixtures. In all experiments, the identification of organic/inorganic molecules formed will be assessed using spectroscopy and examination of the plasma exhaust.

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