Comet Pond II: Synergistic Intersection of Concentrated Extraterrestrial Materials and Planetary Environments to Form Procreative Darwinian Ponds

Abstract

In the “comet pond” model, a rare combination of circumstances enables the entry and landing of pristine organic material onto a planetary surface with the creation of a pond by a soft impact and melting of entrained ices. Formation of the constituents of the comet in the cold interstellar medium and our circumstellar disk results in multiple constituents at disequilibrium which undergo rapid chemical reactions in the warmer, liquid environment. The planetary surface also provides minerals and atmospheric gases which chemically interact with the pond’s organic- and trace-element-rich constituents. Pond physical morphology and the heterogeneities imposed by gravitational forces (bottom sludge; surface scum) and weather result in a highly heterogeneous variety of macro- and microenvironments. Wet/dry, freeze/thaw, and natural chromatography processes further promote certain reaction sequences. Evaporation concentrates organics less volatile than water. Freezing concentrates all soluble organics into a residual liquid phase, including CH3OH, HCN, etc. The pond’s evolutionary processes culminate in the creation of a Macrobiont with the metabolically equivalent capabilities of energy transduction and replication of RNA (or its progenitor informational macromolecule), from which smaller organisms can emerge. Planet-wide dispersal of microorganisms is achieved through wind transport, groundwater, and/or spillover from the pond into surface hydrologic networks.

Macrobiont: Cradle for the Origin of Life and Creation of a Biosphere

“…The availability of HCN for prebiotic organic syntheses has long been considered as plausible for a CO 2 + N 2 atmosphere which is subject to various energetic events, including lightning discharges, UV photochemistry, shocks from hypervelocity bolides [ 31 , 79 ], subaerial hydrothermal systems [ 80 ], or superflare coronal mass ejection events from the early active sun [ 81 ]. HCN can also be delivered exogenously, especially by comets [ 3 , 29 ]. Possibly particularly important is the formation of sodium ferrocyanide [ 82 ] as a temporary safe storehouse of cyanide for feedstock for prebiotic chemical evolution processes [ 83 ].…”

“…The concept of the Macrobiont (MB) [ 1 , 2 , 3 ] is the planetary setting in which the first spark of life was struck from inanimate matter. Before this, each appropriate candidate setting was simply a potential macrobiont (pMB).…”

Prebiotic Sugar Formation Under Nonaqueous Conditions and Mechanochemical Acceleration

“…Contemplated scenarios for the origin(s) of life are as ample as the variety of building blocks, and molecules life is made of [12]. Examples of those are the warm little pond [13], hydrothermal vents [14,15], volcanic environments [16,17], drying lagoons [18,19,20,21], the primordial soup [22,23], eutectic solutions [24,25] or comet ponds [26,27,28]. Whereas each of them addresses distinct open questions in the context of the emergence of life, certain issues remain unresolved.…”

Volatile Species in Comet 67P/Churyumov-Gerasimenko: Investigating the Link from the ISM to the Terrestrial Planets

“…HCN and H2S may thus have been supplied by comets, together with a suite of relevant molecules, including intermediates in the reaction scheme proposed by Patel,et al 197 up to the most basic amino acid glycine 23,81 . Rare events, such as a soft impact on Earth, may have led to ponds of concentrated cometary organics 194 further facilitating the formation of even more complex organic molecules. • (Exo)cometary impacts may significantly alter the atmospheres of exoplanets 211 .…”