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Origins 3D03 Introduction

Origins 3D03 Introduction. Ralph Pudritz & Paul Higgs McMaster University. Introduction to Astrobiology. What is life? Did it originate only on Earth? Recent breakthroughs with great promise: A. on the astrophysical side…

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Origins 3D03 Introduction

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  1. Origins 3D03 Introduction Ralph Pudritz & Paul Higgs McMaster University

  2. 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

  3. 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?

  4. 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?

  5. 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…

  6. 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.

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