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Tori M. Hoehler NASA Ames Research Center

Volcanoes and Impacts in Astrobiology. Tori M. Hoehler NASA Ames Research Center. POP!. A few things have to happen, and a few conditions must be met, to get from there to here. Understanding what these “things” and “conditions” are, and how frequently they occur, is astrobiology. BIG BANG.

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Tori M. Hoehler NASA Ames Research Center

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  1. Volcanoes and Impacts in Astrobiology Tori M. Hoehler NASA Ames Research Center

  2. POP! A few things have to happen, and a few conditions must be met, to get from there to here. Understanding what these “things” and “conditions” are, and how frequently they occur, is astrobiology BIG BANG

  3. Habitability Origin of Life Chemistry Evolution and Continuity The Road to Life?

  4. Although we often think of them in cataclysmic terms, impacts and volcanoes are tied to the story of life in both negative and positive ways.

  5. Volcanoes

  6. Heavily Cratered Surface Suggests Little Evidence of Recent Volcanism on Mercury

  7. Radar Images Suggest Recent Volcanism on Venus

  8. Active Rock Volcanism on Earth

  9. Little Evidence of Volcanism on The Moon

  10. Mars clearly had volcanism once, but how active is it now?

  11. Sulfur Volcanism on Io

  12. IceVolcanism on Enceladus?

  13. Liquid Nitrogen Volcanism on Triton?

  14. Volcanism is a way of transporting heat by moving material (when radiation or conduction just aren’t enough)

  15. Bigger bodies cool more slowly, and may have more active or longer lasting volcanism as a result

  16. Heat is transported by moving hot material from place to place – the material itself may be of great importance

  17. On a differentiated planet, the hot material may come from a chemically different region

  18. Ocean Composition Crustal Alteration Vent Biology Origin of Life Chemistry? Volcanoes Bring Mantle Chemistry to the Surface Atmospheric (Stratospheric!) Chemistry

  19. Creation of Atmosphere (example: Io)

  20. Introduction of H2O and CO2 (oceans and greenhouse)

  21. Introduction of Sulfur and other “heteroatoms” (weather, salt balance, weathering)

  22. Acids

  23. Much of Earth’s “volcanic” activity occurs at the ocean bottom

  24. Submarine volcanism is often manifested by transport of super-heated water (a great solvent, remember?)

  25. Rock Weathering (Bases) + Hydrothermal Alteration + Volcanic Outgassing (Acids) = Salty Ocean

  26. A chemically differentiated planet is like a battery . . . =

  27. Hydrothermal vents transport chemical energy (they tap the Earth’s battery), and this can be harnessed by some microorganisms

  28. Hydrothermal Life on Europa? ?

  29. Impacts . . .

  30. Like volcanoes, impacts transport “stuff” from place to place

  31. Hiroshima year Tunguska century Tsunami danger ten thousand yr. Global catastrophe million yr. K/T billion yr. 0.01 1 100 10,000 million 100 million TNT equivalent yield (MT) Size matters – and so does time Terrestrial Impact Frequency (Credit: D. Morrison)

  32. Impact type matters, too

  33. Impacts deliver energy (Sometimes a little, Sometimes a lot . . . )

  34. Heat energy Earth Titan Apply heat here to make temporarily uninhabitable Apply heat here to make temporarily inhabitable?

  35. Kinetic energy Ejection of Material Suspension in atmosphere? Release from Impacted Planet?

  36. Impacts deliver materials and chemistry from elsewhere in the solar system asteroids comets

  37. Volatiles are “frozen out” in the cold outer reaches of the solar system, and can be delivered to the inner solar system by comets Methane and nitrogen ice coat the surface of Triton

  38. Impacts can deliver organic chemicals – possible importance for origins of life? Organics found in the Murchison meteorite form cell-like vesicles when they contact liquid water (Image credit: David Deamer)

  39. Effects of Impacts on Established Life: E Impact Frustration of Life D’oh

  40. Hiroshima Terrestrial Impact Frequency year Tunguska century Tsunami danger ten thousand yr. Global catastrophe “Armageddon” Impact (Texas-sized!) million yr. K/T billion yr. 0.01 1 100 10,000 million 100 million TNT equivalent yield (MT) (Credit: D. Morrison) “Catastrophic” depends on who you are and where you live . . . “Catastrophic” depends on who you are and where you live . . .

  41. 0 Heat-Sterilized Impact Heating Depth (km) 1 Geothermal Gradient 2 0 100 200 Temperature (°C) Surface-Sterilizing Impacts Habitable (Sleep & Zahnle, 1998)

  42. Effects of Impacts on Established Life: Interplanetary Transfer of Life?

  43. The End

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