III. Ecosmos: A Revolutionary Fertile, Habitable, Solar-Bioplanet, Incubator Lifescape

G. An Astrochemistry to Astrobiological Spontaneity

Yang, Zhenghai, et al.. Low-temperature formation of pyridine and (iso)quinoline via neutral–neutral reactions.. Nature Astronomy.. May, 2024. A global team of astrochemists posted in Hawaii, Florida, Brazil, France and China appear to begin a convergent phase to fill in and unify the original endemic scenario from prebiotic precursors all the way to nucleotide replicators and evolving protocells. See also Co‐evolution of early Earth environments and microbial life by Timothy Lyons, et al in Nature Reviews Microbiology (May, 2024) for a similar paper.

Aromatic molecules represent fundamental building blocks in prebiotic chemistry and are contemplated as vital precursors to DNA and RNA nitrogen bases. However, despite finding some 300 extraterrestrial molecules, the pathways to pyridine (C5H5N), pyridinyl (C5H4N·) and (iso)quinoline (C9H7N) are elusive. Here we describe the gas-phase formation of methylene amidogen (H2CN·) and cyanomethyl (H2CCN·) radicals via molecular beam studies and electronic structure calculations. This study affords entry points to precursors of DNA and RNA nitrogen bases in hydrocarbon-rich environments which changes our understanding of the origin of prebiotic molecules in our Galaxy. (Abstract)

Ziurys, Lucy. Prebiotic Astrochemistry from Astronomical Observations and Laboratory Spectroscopy. Annual Review of Physical Chemistry. Volume 75, 2024. As the quote notes, a senior University of Arizona bioastronomer contends that the profuse ISM population of appropriate biomolecule precursors found so far must have made a vital contribution to the origin and occurrence of nascent Earth life and evolution. See also RNA-catalyzed evolution of catalytic RNA by Nikolaos Papastavrou, et al in PNAS (121/11, 2024) and Complex organic molecules uncover deeply embedded precursors of hot cores by Laure Bouscasse, et al at arXiv:2403.05237 for more evidence of a natural life-bearing spontaneity. Altogether these findings suggest that our worldwise scientific quest may have at last reached an actual realization of a phenomenal ecosmic fertility which proceeds with its own procreative development.

The discovery of more than 200 gas-phase chemical compounds in interstellar space has led to the speculation that this nonterrestrial synthesis may play a role in the origin of life. Interstellar chemistry produces a wide range of organic molecules in dense clouds such as NH2COCH3, CH3OCH3, CH3COOCH3, and CH2(OH)CHO. Elusive phosphorus has now been found in molecular milieu and the sites of star formation. The presence of fertile interstellar starting material, as well as the link to planetary bodies such as meteorites and comets, suggests that astrochemical processes set a prebiotic foundation. (Abstract)

Ziurys, Lucy, et al. Prebiotic Chemical Evolution in the Astrophysical Context. Origins of Life and Evolution of Biospheres. Online April, 2015. University of Arizona astrochemists post a paper presented earlier at ORIGINS 2014 in Nara, Japan which offers further proof of how innately primed cosmic physical substance must be to generate and evolve into increasingly complex biochemical precursors.

Conclusions: Millimeter wavelength astronomical observations are clearly demonstrating that gas-phase molecular material is far more common in the Galaxy than previously thought. Interstellar molecules are increasingly found in significant abundances under harsh environmental conditions. For example, polyatomic species such as H2CO, HCN, and C3H2 are present in planetary nebulae, contained in dense, self-shielding clumps that then seed the diffuse ISM. Molecular material is therefore “recycled” in the ISM, suggesting that chemical timescales could be as long as the lifetime of the Galaxy. Therefore, greater chemical complexity can be achieved than previously thought, perhaps leading to even more complex prebiotic or even biological compounds that could significantly influence the beginning of life on a planet such as the Earth.

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