Origins 3D03 Introduction

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Origins 3D03
Introduction

• Ralph Pudritz Paul Higgs
• McMaster University

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Introduction to Astrobiology

• What is life? Did it originate only on Earth?
• Recent breakthroughs with great promise
• A. on the astrophysical side
• - discovery of extrasolar planets
• - discovery of conditions for planet
  formation around most young stars protoplanetary
  disks
• - discovery of complex organic molecules in
  interstellar gas
• - increasing understanding planetary
  evolution eg. plate techtonics, vulcanism,
  planetary atmospheres, formation of oceans
• - exploration for life in the solar system
  (eg. Mars Rover)
• n

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• B. On the biological/biochemical side
• - discovery of operation of the genetic code
• - genomics and the tree of life
• - discovery of cellular energetics
• - self-assembly of cell membranes
• - discovery of extremophiles, and tracing
  early life
• - hints about operation of earliest genetic
  code
• the RNA world?

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Questions Is life a terrestrial phenonmenon only?

• - What properties define living things?
• eg. reproduction (genetic code)? Cells?
• - Are there laws in biology/biochem that allow
  us to understand emergence of life from simpler
  structures?
• Are these like laws of physics?
• eg. role of energetics entropy (ie
  disorder)
• If not, what basic new principles might be in
  play?
• eg. what does an emergent phenomenon mean?

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Questions Is life universal?

• - Is life an accident in our cosmos, or a natural
  consequence of astrophysical phenomena?
• (eg.- life depends on water, and organic
  molecules and therefore carbon atoms but oxygen
  and carbon produced in stellar interiors. )
• - earth-like planets are made of rock
  formed out dust that was made by stars and
  settled out of gaseous disks around stars

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• An important and useful way of quantitatively
  understanding any system, is to deduce time
  scales.
• Eg. How long has the cosmos existed?
• When did the first stars appear?
• How long does it take to make a
  star?
• When was the solar system formed?
• When did the first life appear?
• What is the average rate of
  evolution?
• What is the average mutation
  rate?
• Answers to these helps constrain processes
  involved.