Comets, Impacts and Astrobiology

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Comets, Impacts and Astrobiology

• Jeremy Bailey (AAO/ACA)
• Deep Impact Workshop Sep 6th 2004

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Deep Impact

• An experiment to study what comets are made of.
• An experiment to create an artificial impact
  crater and study the cratering process.

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Comets and the Origin of Life

• It has been suggested that comets impacting on
  the early Earth may have provided the organic
  building blocks needed for life.
• Do comets contain a rich mix of biologically
  interesting organic molecules (such as amino
  acids)?
• Murchison Meteorite - rich in amino acids
• Are these organic molecules formed in
  interstellar clouds, and therefore abundant in
  the early solar system?
• Can this organic material survive a major impact?
• Simple analysis would suggest it would be
  destroyed by the heat.
• More detailed models and experiments suggest that
  some organic material may be able to survive.

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Life seems to have appeared on Earth around the
end of the Heavy Bombardment Phase.
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Comets and the History of Life

• Life may have been wiped out and started again
  several times.
• Impact frustration hypothesis.
• An early impact might have wiped out all life
  except those organisms adapted to high
  temperature (hyperthermophiles).
• Impacts of comets and asteroids have probably
  played a major part in the later evolution of
  life on Earth.
• K/T impact
• Acraman

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Comets and the future of life

• Is the Earth threatened by future impacts of
  comets and asteroids?
• Deep Impact might be seen as a predecessor of
  missions to destroy/deflect such an object.