The Role of Impacts in Building Biomolecules

Image credit: Simone Marchi

Inorganic methods for synthesizing important life-forming molecules, such as amino acids, have been active fields of study for decades. Different “recipes” involve interactions between inorganic molecules (e.g., CH4, NH3, H2, CO, etc.) and a range of energy sources (e.g., a spark discharge, impact shock, hydrothermal heating, etc.). Many combinations of chemical components and energy sources, based on what was present in Earth’s early history, have been tested extensively in laboratories, and results have found that some combinations produce the necessary reactions more readily than others. On Earth, most chemical environments require a spark source to initiate a significant amount of amino-acid production. However, evidence for ancient impact craters on the lunar surface implies that early Earth was similarly heavily bombarded with material, which could provide not only the energy required, but also supply additional chemical components that could provide new biological pathways.

In a recent study led by Yuto Takeuchi at Tohoku University, Takeuchi and a team of researchers conducted experiments to explore the feasibility of creating life-forming molecules on early Earth and Mars via asteroid impacts. They hypothesized that high-velocity impacts would temporarily generate environments favorable to the formation of biomolecules because iron-bearing impactors provide the energy and reactants required to induce the reactions essential in building organic molecules. Their results demonstrate that high-speed impacts were a source of amino acids on Earth and a potential source on Mars. However, this does not negate other biomolecule forming reactions. Instead, it widens the scope of possible environments and scenarios for synthesizing important life-forming molecules. READ MORE