Simulations of Prebiotic Chemistry under Post-Impact Conditions on Titan

Abstract

The problem of how life began can be considered as a matter of basic chemistry. How did the molecules of life arise from non-biological chemistry? Stanley Miller’s famous experiment in 1953, in which he produced amino acids under simulated early Earth conditions, was a huge leap forward in our understanding of this problem. Our research first simulated early Earth conditions based on Miller’s experiment and we then repeated the experiment using Titan post-impact conditions. We simulated conditions that could have existed on Titan after an asteroid strike. Specifically, we simulated conditions after a potential strike in the subpolar regions of Titan that exhibit vast methane-ethane lakes. If the asteroid or comet was of sufficient size, it would also puncture the icy crust and bring up some of the subsurface liquid ammonia-water mixture. Since, O’Brian, Lorenz and Lunine showed that a liquid water-ammonia body could exist between about 102–104 years on Titan after an asteroid impact we modified our experimental conditions to include an ammonia-water mixture in the reaction medium. Here we report on the resulting amino acids found using the Titan post-impact conditions in a classical Miller experimental reaction set-up and how they differ from the simulated early Earth conditions.

The Astrobiology of Alien Worlds: Known and Unknown Forms of Life

“…The availability of copious organic molecules raises the possibility of complex organic chemistry, leading to biochemistry [115,116]. A possible analog of the hydrocarbon lakes on Titan are liquid asphalt lakes on Earth, such as Pitch Lake in Trinidad where deep saltwater mixes with hydrocarbons, somewhat analogous to ammonia-water slurries that mix with hydrocarbon reservoirs on Titan.…”

Intrinsic and Extrinsic Thermodynamics for Stochastic Population Processes with Multi-Level Large-Deviation Structure

“…The motivation for the model is a question from astrobiology: in how far can two environments be considered analogues simply because they produce similar distributions for a material considered to be of biological interest. For instance, is Titan an analogue to early Earth if both are believed to support significant polymerization of small organic molecules [ 112 , 113 , 114 ], even if polymers on Titan are stable and near equilibrium at low water activity, whereas Earth produced them (putatively) through a competition between ligation driven by disequilibrium leaving groups such as phosphates [ 115 , 116 ] or thioesters [ 117 , 118 ] and disequilibrium hydrolysis?…”

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“…Investigations have therefore focused upon the possibility of using morphological traces, as occur in rocks on Earth, to indicate signs of past bacterial motility (Krepski et al , 2013 ; Rivera and Sumner, 2014 ). In contrast to past missions, missions over the next several decades will prioritize targets within the Solar System that contain abundant liquid water: Europa (Squyres et al , 1983 ; Carr et al , 1998 ), Enceladus (Tsou et al , 2012 ; Hsu et al , 2015 ), Titan (Rampelotto, 2012 ; Turse et al , 2013 ; McLendon et al , 2015 ), and Ganymede (McCord et al , 2001 ; Saur et al , 2015 ) are all examples.…”