When Did Life Likely Emerge on Earth In An RNA-First Process?
The widespread presence of ribonucleic acid (RNA) catalysts and cofactors in Earth’s biosphere today suggests that RNA was the first biopolymer to support Darwinian evolution.
However, most “path-hypotheses” to generate building blocks for RNA require reduced nitrogen-containing compounds not made in useful amounts in the CO2-N2-H2O atmospheres of the Hadean. We review models for Earth’s impact history that invoke a single ~10^23 kg impactor (Moneta) to account for measured amounts of platinum, gold, and other siderophilic (“iron-loving”) elements on the Earth and Moon. If it were the last sterilizing impactor, Moneta would have reduced the atmosphere but not its mantle, opening a “window of opportunity” for RNA synthesis, a period when RNA precursors rained from the atmosphere to land holding oxidized minerals that stabilize advanced RNA precursors and RNA.
Surprisingly, this combination of physics, geology, and chemistry suggests a time when RNA formation was most probable, ~120 +/- 100 million years after Moneta’s impact, or ~4.36 +/- 0.1 billion years ago. Uncertainties in this time are driven by uncertainties in rates of productive atmosphere loss and amounts of sub-aerial land.
Steven A. Benner, Elizabeth A. Bell, Elisa Biondi, Ramon Brasser, Thomas Carell, Hyo-Joong Kim, Stephen J. Mojzsis, Arthur Omran, Matthew A. Pasek, Dustin Trail
(Submitted on 29 Aug 2019)
Comments: Paper accepted to ChemSystemsChem [this https URL] August 22, 2019
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Biological Physics (physics.bio-ph); Chemical Physics (physics.chem-ph); Geophysics (physics.geo-ph)
Cite as: arXiv:1908.11327 [astro-ph.EP] (or arXiv:1908.11327v1 [astro-ph.EP] for this version)
Submission history
From: Stephen Mojzsis
[v1] Thu, 29 Aug 2019 16:17:55 UTC (1,641 KB)
https://arxiv.org/abs/1908.11327
Astrobiology, Genomics
