Building Blocks of Life on Early Earth and Mars Under the Young Sun

Recent Kepler and TESS observations combined with our 3D MHD simulations of the corona-wind system of young solar analogs that suggests that the early Earth and Mars have been exposed to high level of ionizing radiation and frequent SEP events. What is the impact of this high-energy radiation on atmospheric chemistry of the early terrestrial type planets? Here we present our recent results from the 1D photochemical and collisional chemistry atmospheric model of the weakly reducing atmospheres of early Earth and Mars. We show that as energetic protons can reach the lower atmospheres of the early Earth and Mars, induce ionization, and thus produce cascades of impact electrons that are instrumental in exciting, ionizing and dissociating molecular nitrogen, carbon dioxide, methane and water vapor. The consistent steady state solution of the resulted atmospheric chemistry suggests the formation of abundant nitrous oxide (N2O), hydrogen cyanide (HCN) and more complex molecules in the gas phase. This model suggests that two fundamental paradoxes for the early Earth environments, the origin of prebiotic chemistry on early Earth and the Faint Young Sun (FYS) paradox can be addressed within a unified chemical network driven by the persistent energy sources from the young Sun. While nitrous oxide is a potent greenhouse gas, which is capable of warming the early Earth atmosphere, the formation of abundant hydrogen cyanide and associated building blocks of life. While the resolution of the FYS paradox can explain the existence of the standing bodies of liquid water on early Earth's surface, water is a crucial ingredient of forming formamide that promotes further polymerization of building blocks of life on the planetary surfaces. Our recent laboratory experiments performed at Yokohama National University using the proton accelerator at Tokyo Institute of Technology provide suggest that SEP driven protons are a crucial energy source in producing of amino acids and other complex molecules in a weakly reducing gas environment. The proton ignited production rates of amino acids are by 5 orders of magnitude greater as compared to lightning and UV energy sources. We combine these theoretical and experimental results to conclude that the high energy ionizing radiation from the young Sun and active stars has a high potential to promote the formation of the major ingredients of biogenic habitability on the early Earth, Mars and Earth-like exoplanets.