2023-05-26 20:00:00
The appearance of prebiotic organic compoundsthat is, the reactive organic molecules necessary to form the basic components of life on Earth, was an essential step for the origin of life on our planet.
The formation of a stable continental crust and liquid water on its surface about 4.4 billion years ago, and the first biogenic carbon isotope signatures, dated to between about 3.8 and 4.1 billion years ago, suggest that life originated during the first 400 and 700 million years after the formation of our planet, during the Hadean eon.
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In this sense, to explain the emergence of the first components of life, scientists have considered different hypotheses for decades. Some of them defend that these could come from the very nebula in which our star and our planetary system were formed, or from the asteroids and comets that bombarded our planet already during the earliest stages of its formation.
Others, on the other hand, suggest that high-energy processes such as lightning strikes, or the chemical reactions associated with submarine vents, were responsible for generating the culture medium necessary for the formation of the first organic molecules. However, in the absence of conclusive data, it remains unclear what was the predominant mechanism that produced these prebiotic precursors.
Another of the most solid hypotheses in this regard suggests that they were meteorite particles or ash deposited on volcanic islands those that could have promoted the conversion of atmospheric carbon dioxide into precursors of organic molecules on the early Earth. And this is precisely the hypothesis that the researcher from the Ludwig-Maximilian University of Munich and the Max Planck Institute for Astronomy, Oliver Trappwanted to test in a study that under the title Synthesis of prebiotic organics from CO2 by catalysis with meteoritic and volcanic particles is published this week in the magazine Nature.
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To do this, Trapp’s team simulated the variety of conditions that might have been present on the early Earth. Thus, they recreated an atmosphere rich in carbon dioxide in an isolated system at pressures ranging from 9 to 45 bars and temperatures ranging from 150°C to 300°C. They also simulated wet and dry weather conditions by adding hydrogen gas or water to the system eiThey mitigated the presence of meteorites or ash particles by adding different combinations of crushed samples of iron meteorites, stony meteorites, or volcanic ash to the system.
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The authors found that, under a wide range of atmospheric and climatic conditions that might have been present on the early Earth, iron-rich particles from meteorites and volcanic ash catalyzed the conversion of carbon dioxide into hydrocarbons, aldehydes, and alcohols. They observed that aldehydes and alcohols formed at lower temperatures, while hydrocarbons formed at 300°C.
The authors suggest that as the early Earth’s atmosphere cooled over time, the production of alcohols and aldehydes may have increased, and that these compounds would have been key in the reactions that would have led to the formation of carbohydrates, lipids, sugars, amino acids and ultimately DNA and RNA.
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