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Conversations with the Earth Tom Burbine tburbine@framingham.edu

Conversations with the Earth Tom Burbine tburbine@framingham.edu. Final. May 9 (Monday) – 11:30 am - (Monday, Wednesday, Thursday class) May 11 (Wednesday) – 8 am - (Tuesday, Thursday class) 25 short answer questions No calculators

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Conversations with the Earth Tom Burbine tburbine@framingham.edu

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  1. Conversations with the EarthTom Burbinetburbine@framingham.edu

  2. Final • May 9 (Monday) – 11:30 am - (Monday, Wednesday, Thursday class) • May 11 (Wednesday) – 8 am - (Tuesday, Thursday class) • 25 short answer questions • No calculators • Besides your new sheet of paper, you can bring in the sheet of paper you used for the Midterm

  3. Grade Distribution • 1 9919 8935 8452 76 • 2 9819 8935 8456 75 • 2 9819 8935 8457 74 • 2 9819 8940 8358 73 • 5 9723 8840 8358 73 • 5 9723 8842 8260 70 • 7 9623 8842 8261 69 • 8 9523 8842 8262 68 • 9 9427 8745 7962 68 • 10 9327 8745 7964 66 • 10 9327 8745 7965 61 • 10 9327 8745 7966 59 • 13 9231 8649 7867 50 • 14 9131 8649 7868 44 • 15 9033 8551 7769 42 • 15 9033 8552 7670 39 • 15 9035 8452 7671 38 • 15 9035 8452 7672 25

  4. Types of Planetary Missions • Fly By • Orbiter • Lander • Atmospheric Probe • Rover • Manned • Sample Return

  5. Water on Mars • Most of the water is frozen (permafrost and polar caps) • No bodies of liquid water, which could create a hydrosphere • Only a small amount of water vapor is in the atmosphere

  6. How did Mars lose its water?

  7. How did Mars lose its water? • One possibility: • On Earth, we're protected from the solar wind by a global magnetic field • Mars appears to have had a global magnetic field, which turned off • When it turned off, Mars’ atmosphere may have been eroded by the solar wind

  8. Basic Definition of Life • Growth • Metabolism • Motion • Reproduction • Stimulus response

  9. ALH 84001 • Allan Hills 84001 • Martian meteorite found in Antarctica • Thought to have evidence for life (1996)

  10. Meteorites from Mars • Are called SNCs • Shergottites, Nakhlites, Chassignites • Shergotty • Nakhla • Chassigny • 34 Martian meteorites currently known

  11. How do we know they are from Mars? • Most have young formation ages (1.35 and 0.15 billion years) • Gases in glass in meteorites match Mars

  12. Evidence • organic molecules • Magnetite (Fe3O4) that looks like it formed from biologic activity • nanofossil-like structures

  13. Age of ALH 84001 • ALH 84001 - 4.5 billion years • But has same oxygen isotope ratio as other Martian meteorites so it comes from Mars • Oldest meteorites are 4.56 billion years

  14. Face on Mars Face is 1.5 km across

  15. Significant Mars Missions • Viking 1 (1976-1982) (NASA) (Lander) • Viking 2 (1976-1980) (NASA) (Lander) • Mars Global Surveyor (1993-2006) (NASA) (Orbiter) • Mars Pathfinder (1997) (NASA) (Lander) • Mars Express (2003-present) (ESA) (Orbiter) • MER Spirit (2004-present) (NASA) (Lander) • MER Opportunity (2004-present) (NASA) (Lander) • Mars Reconnaissance Orbiter (2006-present) (NASA) (Orbiter) • Phoenix (2008) (NASA) (Lander)

  16. Viking Missions • Each spacecraft consisted of an orbiter and a lander • Viking 1 lander landed July 20, 1976 • Viking 2 lander landed September 3, 1976 • Total cost was ~1 billion

  17. Viking 2

  18. Viking 2

  19. Four Experiments • There were results that were initially positive • But results could all be explained through non-biologic chemistry • For example, Labeled Release Experiment • The nutrients were tagged with radioactive 14C • Looked for emitted 14CO2 gas as evidence for chemical reactions that happen in living organisms to maintain life • Radioactive gases were given off immediately for the first insertion of nutrients • Subsequent insertions did not give off radioactive gases

  20. Europa (Moon of Jupiter)

  21. Europa • Very smooth surface • Its albedo is one of the highest of all moons • Lack of craters indicates a young and active surface • Thought to have a liquid water ocean • Possibly abode of extraterrestrial life

  22. Symmetric ridges in the dark bands suggest that the surface crust was separated and filled with darker material, somewhat analogous to spreading centers in the ocean basins of Earth.

  23. Spectroscopy suggests that the dark reddish streaks and features on Europa's surface may be rich in salts such as magnesium sulfate (Epsom salt), deposited by evaporating water that emerged from within.

  24. Europa • It is thought that under the surface there is a layer of liquid water kept warm by tidally generated heat.

  25. Proposed Europa Jupiter System Mission (NASA/ESA) (~2020)

  26. Any Questions?

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