1. Panspermia The Search for your mothers mother

2. Overview Panspermia- Origin of Earth’s life from elsewhere Panspermia- Origin of Earth’s life from elsewhere Interplanetary Interplanetary Interstellar Interstellar Asking the right questions: no answers in this presentation Asking the right questions: no answers in this presentation Probability of life starting on Earth Vs. on another planet Probability of life starting on Earth Vs. on another planet Enough time for life to evolve on earth? Enough time for life to evolve on earth? Getting that life here Getting that life here Ejection Ejection transport: radiation, vacuum, travel time, cold temperature transport: radiation, vacuum, travel time, cold temperature entry entry

3. Panspermia Vs. Terrestrial origins of life Earth’s accretion, core formation, and degassing complete 4.47 Ga (Halliday) Earth’s accretion, core formation, and degassing complete 4.47 Ga (Halliday) End of Intense bombardment 3.9 Ga (Halliday) End of Intense bombardment 3.9 Ga (Halliday) Earliest life 3.5 Ga, 3.8 Ga? (Hayes) 3.85- 4.25 Ga? (Mojzsis) Earliest life 3.5 Ga, 3.8 Ga? (Hayes) 3.85- 4.25 Ga? (Mojzsis) Was there enough time for life to evolve or was the earth seeded? Was there enough time for life to evolve or was the earth seeded?

4. Are we alone? Other life in our Solar System? Venus Venus Mars Mars Europa Europa Titan Titan More likely on those planets? More likely on those planets?

5. Life originating on Mars Vs Earth Early mars: Early mars: Ozone (pavlov et al., 2001) Ozone (pavlov et al., 2001) Oxygen Oxygen Magnetic Field providing protection (Acuna et al., 1999) Magnetic Field providing protection (Acuna et al., 1999) Early Earth: Early Earth: No Ozone (pavlov) No Ozone (pavlov) No oxygen No oxygen Early Mars compared to early earth better place for origin of life (Kirschvink, 2002) Early Mars compared to early earth better place for origin of life (Kirschvink, 2002)

6. Are we alone? Life elsewhere in the Universe Earth like planets PFR Earth like planets PFR Stellar Systems with habitable planets in the milky way Stellar Systems with habitable planets in the milky way GSM model (dashed) GSM model (dashed) GDM model (solid) GDM model (solid) (Bloh, 2002) More time for evolution of life to occur More time for evolution of life to occur 6 Ga 6 Ga

7. Types of Panspermia Lithopanspermia-within stone Lithopanspermia-within stone Radiopanspermia-single spermia across space Radiopanspermia-single spermia across space Directed Panspermia ( Aliens ) Directed Panspermia ( Aliens )

8. Difficulties of Panspermia Escape from seed planet Escape from seed planet Interplanetary/stellar travel Interplanetary/stellar travel Radiation Radiation Vacuum Vacuum Extreme temperatures Extreme temperatures Entry to seeded planet Entry to seeded planet

9. Survivability of ejection and entry Temperature: ALH48001 increased temperature by only up to 40 degrees Celsius during ejection and entry (Weiss et al., 2000) Temperature: ALH48001 increased temperature by only up to 40 degrees Celsius during ejection and entry (Weiss et al., 2000) Accelerations of 4.27x10^6 m/s^2 10% survival rate (Mastrapa et al., 2000) Accelerations of 4.27x10^6 m/s^2 10% survival rate (Mastrapa et al., 2000) Mars 3x10^6 Mars 3x10^6 Difficulty accelerating small particles Difficulty accelerating small particles Shocks of 32 GPa 1 in 10^4 survive (Horneck et al., 2001) Shocks of 32 GPa 1 in 10^4 survive (Horneck et al., 2001) Mars 20-45 Gpa Mars 20-45 Gpa

10. Length of time surviving in space Radiation: Need shielding Radiation: Need shielding For 10% chance of survival: For 10% chance of survival: 0.1 myr-40 myr depending on shield thickness (Mileikowsky et al., 2000) 0.1 myr-40 myr depending on shield thickness (Mileikowsky et al., 2000) 1 myr (Parson, 1996) 1 myr (Parson, 1996) 45 myr (Weber and Greenberg, 1985) 45 myr (Weber and Greenberg, 1985) 250 myr (Vreeland et al., 2000) 250 myr (Vreeland et al., 2000) ALH48001 transport time ALH48001 transport time 10,000 to 100 mya transport time via heliocentric orbit 10,000 to 100 mya transport time via heliocentric orbit Possibility of 1 year transport time 1x10^-7 (Burchell, 2003) Possibility of 1 year transport time 1x10^-7 (Burchell, 2003)

11. (Bloh, 2003) With square of distance impacts become less likely

12. Likelihood of Interstellar panspermia “It is very unlikely that even a single meteorite originating on a terrestrial planet in our solar system has [ever] fallen onto a terrestrial planet in another stellar system.” (Melosh, 2003) “It is very unlikely that even a single meteorite originating on a terrestrial planet in our solar system has [ever] fallen onto a terrestrial planet in another stellar system.” (Melosh, 2003) Only 1-2 meteorites captured by another solar system post heavy bombardment Only 1-2 meteorites captured by another solar system post heavy bombardment 1 in 10 k chance of captured meteorite actually strikes a terrestrial planet (Melosh, 2003) 1 in 10 k chance of captured meteorite actually strikes a terrestrial planet (Melosh, 2003) Too long transport time for life to survive? Too long transport time for life to survive?

13. Summary Solar system’s planets more likely than earth to have harbored life? Solar system’s planets more likely than earth to have harbored life? Interstellar planets much farther away Interstellar planets much farther away Less likely for panspermia event to occur Less likely for panspermia event to occur More likely for life to have evolved More likely for life to have evolved Is the (improbable?) traveling from another planet more likely to have occurred than life evolving on earth? Is the (improbable?) traveling from another planet more likely to have occurred than life evolving on earth?

14. Direct Seeding

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