1. What are the effects of bombardment?

    • What role does bombardment play in the origin of life on Earth or elsewhere?

    • Did life emerge during the heavy bombardment of the Hadean era?

    • How do rocky planets get wet?

    • What are the frequency and effect of subsequent bombardments?

  1. What is the biological role of radiation?

    • What fraction of mutations are due to copy errors, to influences from within the biosphere, and to external astronomical sources?

    • Is the level of mutations a selected biological phenotype?

    • To what degree and under what conditions is chiral asymmetry, and possibly homochirality, induced by radiation?

    • What is the evolutionary origin of radiation repair mechanisms and what commonality is there between these mechanisms, gene transfer, and meiois, all of which involve annealing strands of DNA?

    • Is photosynthesis a requirement for a highly developed biosphere?

  1. What programmatic activities at NASA and other agencies can be developed to detect/confirm/ verify factors relevant to the topics outlined above?

    • Are there in vitro or in silico experiments that can inform these issues outlined above?

    • How do current and proposed NASA missions support prospects for the remote sensing of the geology, climate, weather, chemistry, and biology of planets around other stars?

    • What additional missions can be developed to address these issues?



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