New Signatures of Bio-Molecular Complexity in the Hypervelocity Impact Ejecta of Icy Moon Analogues

Abstract

Impact delivery of prebiotic compounds to the early Earth from an impacting comet is considered to be one of the possible ways by which prebiotic molecules arrived on the Earth. Given the ubiquity of impact features observed on all planetary bodies, bolide impacts may be a common source of organics on other planetary bodies both in our own and other solar systems. Biomolecules such as amino acids have been detected on comets and are known to be synthesized due to impact-induced shock processing. Here we report the results of a set of hypervelocity impact experiments where we shocked icy mixtures of amino acids mimicking the icy surface of planetary bodies with high-speed projectiles using a two-stage light gas gun and analyzed the ejecta material after impact. Electron microscopic observations of the ejecta have shown the presence of macroscale structures with long polypeptide chains revealed from LCMS analysis. These results suggest a pathway in which impact on cometary ices containing building blocks of life can lead to the synthesis of material architectures that could have played a role in the emergence of life on the Earth and which may be applied to other planetary bodies as well.

A Computational Quantum-Based Perspective on the Molecular Origins of Life’s Building Blocks

“…The shocked ice samples were then analyzed showing the presence of a series of amino acids, including glycine, (D)-alanine, (L)-alanine, and (L)-isovaline [ 16 ]. Similar experiments have more recently been performed by Singh et al [ 120 ] at the same facility [ 121 ] by using more complex bullets composed of icy amino acids which, after being shot at a speed of ∼5 km· , have been transformed into complex biological structures such as peptides and membranelike structures.…”

“…The fact that glycine and other prebiotically relevant species were detected in non-negligible amounts in some comets, such as Halley, Hyakutake, Tempel-1, Giacobini–Zinner, Hartley 2 and Hale–Bopp, 81P/Wild 2 [ 105 , 106 , 107 , 108 , 109 , 110 , 111 ], indirectly suggested the possibility to observe and reproduce a relatively complex chemistry when high-energy impacts take place. In fact, many interesting experimental and computational results emerge from disparate investigations of the catalytic effects produced by violent mechanical stresses acting on simple inorganic systems [ 7 , 16 , 18 , 36 , 39 , 42 , 104 , 112 , 113 , 114 , 115 , 116 , 117 , 118 , 119 , 120 , 120 ]. As an example, Martins et al [ 16 ] created several icy bullets composed of simple compounds ubiquitous in cometary ices such as ammonium hydroxide (NH 4 OH), carbon dioxide (CO 2 ), and methanol (CH 3 OH), which were impacted on a series of rocky surfaces—mimicking planetary surfaces—by using a light gas gun available at an important facility located at the University of Kent [ 121 ].…”

A Comparative Investigation on the Structural Stability of the Single and Poly‐Crystalline Sodium Nitrate at Dynamic Shock Wave Loaded Conditions

“…Analyzing the impact of shock waves on the surface characteristics of the crystalline and non‐crystalline samples at dynamic shock wave exposed conditions is one of the interesting research areas by which the nature of the aftermath effect of the crystallographic structural phase features experienced by the samples could be identified specifically. [ 54 ] Recently, Surendra Singh and his research group have demonstrated the shock wave processing on amino acid materials and a few bio‐molecular complex materials and they have found significantly modified surface morphologies at shocked conditions. [ 54 ] Furthermore, technologically important inorganic material of ammonium dihydrogen phosphate poly‐crystalline material has been subjected to shock waves and performed the particle surface analysis by which it has been found that, during the shocked conditions, the prismatic face undergoes a significant defect formation.…”

“…[ 54 ] Recently, Surendra Singh and his research group have demonstrated the shock wave processing on amino acid materials and a few bio‐molecular complex materials and they have found significantly modified surface morphologies at shocked conditions. [ 54 ] Furthermore, technologically important inorganic material of ammonium dihydrogen phosphate poly‐crystalline material has been subjected to shock waves and performed the particle surface analysis by which it has been found that, during the shocked conditions, the prismatic face undergoes a significant defect formation. [ 47 ] In addition to that, as per the previous article, during the shocked conditions, single‐crystalline NaNO 3 crystals experience significant changes on the surface of the crystals.…”

Icy ocean worlds, plumes, and tasting the water

“…It has long been known that impacts can produce more complex molecules from simpler precursors (e.g., Bar-Nun et al, 1970;Blank et al, 2001;Peterson et al, 1997;Sugahara & Mimura, 2015;Takeuchi et al, 2020). Of particular interest here is that, it has previously been shown that impacts involving ices can drive chemistry (e.g., Bowden et al, 2009;Nna-Mvondo et al, 2008;Singh et al, 2022). Indeed, it has also been shown that amino acids can be produced in impacts onto ices (Martins et al, 2013).…”