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Abstract:

Context. It is well known that hydrogen cyanide and formamide can universally be considered as key molecules in prebiotic synthesis. Despite the fact that formamide has been detected in interplanetary and interstellar environments, other prebiotic species are far more abundant, including, for example, formaldehyde. However, several results indicate that formamide can play the role of important intermediate as well as that of a feedstock molecule in chemical abiogenesis. Diverse recently proposed scenarios of the origins of the first biopolymers show that liquid formamide environments could have been crucial for the formation of nucleobases, nucleosides, and for phosphorylation reactions, which lead to nucleotides.Aims.Here we report on a wide exploration of the formaldehyde reaction network under plasma conditions mimicking an asteroid descent in an Earth-like atmosphere and its impact.Methods.Dielectric breakdown using a high-power kJ-class laser system (PALS – Prague Asterix Laser System) along with quantum mechanical, ab initio molecular dynamics, and enhanced sampling simulations have been employed in order to mimic an asteroid impact plasma.Results.Being more abundant than formamide both in interstellar and interplanetary environments, during the era of early and late heavy bombardment of Earth and other planets, formaldehyde might have been delivered on asteroids to young planets. In the presence of nitrogen-bearing species, this molecule has been reprocessed under plasma conditions mimicking the local environment of an impacting body. We show that plasma reprocessing of formaldehyde leads to the formation of several radical and molecular species along with formamide.Conclusion. All the canonical nucleobases, the simplest amino acid (i.e., glycine), and the sugar ribose, have been detected after treatment of formaldehyde and nitrogen gas with dielectric breakdown. Our results, supported by quantum mechanical and enhanced sampling simulations, show that formaldehyde – by producing inter alia formamide – may have had the role of starting substance in prebiotic synthesis.

Abstract:

Scientists have been striving to find a theory which would describe the origin of life on Earth for centuries, so far without success. To succeed in solving these problems, one has to broaden their view, to approach the scientific subject from a philosophical standpoint, to set firmly a framework of the research and to define its borders. In order to asses the philosophical contribution of the work, one need not resort to new ideas only, because many ideas have already been expressed in the past. Such concepts are nowadays often remembered only in History of arts and Philosophy classes. In our recent article published in Nature Astronomy, we have presented a very complex model for the creation of methane and its reprocessing to more complex organic molecules including nucleic acid bases from simple gaseous precursors. The purpose of this work is to show the repeating cycle of the creation of complex molecules from CO2 and their subsequent destruction back to their basic parent molecules in the light of the 500-year-old idea of the creation of life by Hieronymus Bosch.