Conversations with the Earth Tom Burbine [e-mail]

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Conversations with the EarthTom
Burbinetburbine_at_framingham.edu
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Final

• May 9 (Monday) 1130 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

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Grade Distribution

• 1 99 19 89 35 84 52 76
• 2 98 19 89 35 84 56 75
• 2 98 19 89 35 84 57 74
• 2 98 19 89 40 83 58 73
• 5 97 23 88 40 83 58 73
• 5 97 23 88 42 82 60 70
• 7 96 23 88 42 82 61 69
• 8 95 23 88 42 82 62 68
• 9 94 27 87 45 79 62 68
• 10 93 27 87 45 79 64 66
• 10 93 27 87 45 79 65 61
• 10 93 27 87 45 79 66 59
• 13 92 31 86 49 78 67 50
• 14 91 31 86 49 78 68 44
• 15 90 33 85 51 77 69 42
• 15 90 33 85 52 76 70 39
• 15 90 35 84 52 76 71 38
• 15 90 35 84 52 76 72 25

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Types of Planetary Missions

• Fly By
• Orbiter
• Lander
• Atmospheric Probe
• Rover
• Manned
• Sample Return

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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

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How did Mars lose its water?
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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

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Basic Definition of Life

• Growth
• Metabolism
• Motion
• Reproduction
• Stimulus response

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ALH 84001

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

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Meteorites from Mars

• Are called SNCs
• Shergottites, Nakhlites, Chassignites
• Shergotty
• Nakhla
• Chassigny
• 34 Martian meteorites currently known

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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

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Evidence

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

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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

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Face on Mars
Face is 1.5 km across
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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)

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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

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Viking 2
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Viking 2
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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

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Europa (Moon of Jupiter)
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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

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• 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.

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• 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.

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Europa

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

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Proposed Europa Jupiter System Mission (NASA/ESA)
(2020)
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Any Questions?