Formation of the Solar Sytem and Earth

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Formation of the Solar Sytemand Earth

• Scott Robowski
• Geology 5032

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Ideas that Need to Be Addressed by Theories

• Patterns of Motion Among
• Large Bodies
• Two Major Types of Planets
• Asteroids and Comets

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Approximately 4.6 Billion Years Ago

• How do we know time?
• radioactive dating of early rocks
• Composition of Material
• hydrogen, helium (98) and
• heavier elements (2)

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Where Did the Material Come From?
? 2005 Pearson Education, Inc
5
What Was Created
? 2005 Pearson Education, Inc
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Rene Descartes

• Solar system is like an
• eddy in a stream
• Material collects at center of eddy (Sun) and
  other materials flows around it
• Did not explain comets/meteors

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Immanuel Kant

• Sun and planets condensed out of a spinning
  nebula
• Could not explain formation of planets

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Pierre-Simon Laplace

• Added to Kants theory
• Spinning disk of material was not flat - density
  allowed for formation of planets

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Georges L.L. Buffon

• A comet approaches closely to the sun and pulls
  away material
• Material forms the planets

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Svante Arrhenius

• First to propose the idea of
• the sun colliding with a foreign star releasing
  matter that evenually formed the solar system

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T.C. Chamberlain andF.R. Moulton

• Close meeting of the sun
• with a passing foreign star
• Gaseous trail siphoned away
• from sun and created solar
• system

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C.F. von Weizsäcker and Gerald Kuiper

• Combined Nebular and Planetesimal Ideas
• Helped to address key components in theory

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Collision of Planetesimals
? 2005 Pearson Education, Inc
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Evidence for Nebular Theory

• Hubble has taken pictures of dust disk around
  other stars
• Computer simulations show condensation of
  planetesimals

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Terrestrial vs. Gaseous Planets
? 2005 Pearson Education, Inc
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Summary
? 2005 Pearson Education, Inc
17
Earth

• Created in the warmer inner region of dust ring
• Terrestrial planets were
• initially molten due to heat from radioactive
  decay, gravitational compression, and
  impacts from planetesimals

? 2005 Pearson Education, Inc
18

• When Earth was molten, dense iron and nickel sank
  to the core and lighter silicates floated to the
  top
• Earth did not have the gravity to keep the
  hydrogen and helium gases contained. They
  escaped into outer space
• Around 3.8 billion years ago, Earth was cool
  enough for liquid water to condense and early
  sedimentary rock formed