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Origin of Earth and Ocean

Origin of Earth and Ocean. Scientific Observations and Explanations on the Origin and Evolution of Earth’s Ocean. GEOL100 - Physical Geology. Ray Rector - Instructor. Preview of Topics. Origin of the Universe Origin of the Solar System Origin of Earth-Moon System

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Origin of Earth and Ocean

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  1. Origin of Earth and Ocean Scientific Observations and Explanations on the Origin and Evolution of Earth’s Ocean GEOL100 - Physical Geology Ray Rector - Instructor

  2. Preview of Topics • Origin of the Universe • Origin of the Solar System • Origin of Earth-Moon System • Origin of the Ocean and Atmosphere • Origin of Life • The Age of the Earth

  3. A Twisted COSMIC Timescale Starting with the Big Bang event 13.7 billion years ago, and evolving to the present day.

  4. The Visible and Invisible Universe The Basic Components • Expanding Space • 4 Fundamental Forces • Energy - EMR • Matter • Dark energy • Dark Matter 13.7 Billion Years of Creation and Destruction

  5. How Much Stuff Is Out There? The Rough Stats: 1) Size: 30 x 109 cubic light years • 1x106 light yrs between galaxies 2) Matter: 100 billion galaxies • 1.6 x 1060 kilograms @ 1.4 kg per cubic meter 3) Only 0.0000000000000000000042 % of the universe contains any matter • It’s a SUPER empty place! • Position in the sky and the extent of the magnification Every spot of light is a galaxy! Hubble Deep Field Image

  6. Survey of Elements Found in Universe • 92 Naturally-occurring elements • Predominantly Hydrogen and Helium • Lots of Carbon, Nitrogen, Oxygen, Silica, Sulfur, and common metals • Minor amounts of rare earth and very heavy elements Questions: 1) What processes made the elements? 2) Why the three-step, relative abundance distribution of the elements?

  7. BIG BANG Theory -14 Billion Years of Cosmic Evolution The Big Bang Elements:Hydrogen and Helium were the two major elements generated in cosmically-massive amounts soon after the initial Big Bang event – very little else. ?

  8. The Fate of Our Universe? Possible Outcomes 1) The Big Freeze • Expand forever • Cold and Dark 2) The Big Crunch • Collapse • Prelude to BB#2? 3) The Big Rip • Runaway dark energy • Anti-gravity tears apart all matter

  9. Galaxies – Gigantic Star Clusters Key Points: • Galaxies are “island universes” where stars are born, live and die • Gravity is the controlling force on galaxy formation and evolution • Universe contains roughly 100 billion stars • Typical galaxy contains 100 billion stars • A typical star located in a galaxy is much like our Sun • Stars generate new elements during fusion and nova • All elements except for the very light ones can only form inside stars • Our galaxy – the Milky Way – looks very much like our neighbor – the Andromeda galaxy. Circus of Galaxies Andromeda Galaxy

  10. Our Very Own Island Universe Milky Way Galaxy • Milky Way Galaxy is 100 million light in diameter • Our galaxy contains roughly 400 billion stars • Sun is a very typical star located in one of the arms of the Milky Way Galaxy • Other planetary systems have been found in our galaxy We are here

  11. Nebula – Star Nurseries • Nebula are regions of dense hot gases, stellar debris, and very young stars • New stars and planetary systems form from the both primordial matter and the remnants of exploded stars within nebula • Our solar system most likely formed in a nebula much like this one • Condensation Theory for star and planet formation Carina Nebula

  12. Observed Stellar Systems in the Making Observations of Newly Forming Stars Within a Nebula Cloud The Trifid Nebula The Nebula Condensation Theory best explains the formation of stellar systems such as ours

  13. Stellar Fusion – The Element Factory The Fusion Process Three-Stage Star Evolution 1) Normal Star = Helium 2) Red Giant Star = Carbon Note: Stellar fusion processes generate the light to medium weight elements: from Helium (He) all the way up to Iron (Fe). 3) Red Supergiant Star = Neon through Iron

  14. Supernova – Heavy Element Factory Stellare Implosion – Explosion Process Collapse of Red Supergiants Tycho-supernova Note: Supernova processes generate the medium- to heavyweight elements: from Iron (Fe) all the way up to Uranium (U) Supernova Process

  15. We are here Our Solar System • 4 Inner Planets • Mercury • Venus • Earth • Mars • 4 Outer Planets • Jupiter • Saturn • Uranus • Neptune What about poor little Pluto?

  16. The Nebula Condensation Theory Animation1 Animation2

  17. Origin of the Moon Multiple Theories • Twin Planet Theory • Moon Capture Theory • Earth-Birthed Theory • Giant Impact Theory

  18. Most Likely Origin of the Moon Giant Impact Theory Impact Sequence of Earth and Mars-size Body The Giant Impact Theory best explains formation of the moon, based on physical and chemical data

  19. Density Differentiation of Young Earth Early-stage Differentiation Model • Proto-earth was homogenous • Proto-earth underwent complete melting due to accretion energy and radioactive decay • Heaviest elements sank down to form core – mainly iron and nickel • Medium weight elements formed mantle and crust– mainly silicate minerals • Lighter elements floated up to form ocean and atmosphere

  20. Composition and Structure of Earth Five Chemically Distinct Layers Eight Physically Distinct Layers

  21. Formation of the Earth’s Ocean and Atmosphere The Origins of Earth’s Atmosphere and Ocean are Closely Tied Together The Composition of the Atmosphere Has Greatly Changed Over the Last Four Billion Years The Composition of Ocean Initially Changed Over the First Billion Years But Has Since Remained Stable

  22. Evolution of Earth’s Atmosphere • Three Stages • Primordial Atmosphere ??? • Hydrogen and helium from original condensed nebula • Probably stripped away by early solar wind and heating 2) Secondary Atmosphere • Volcanic outgassing of volatiles from inside planet • Primarily water and carbon dioxide with sulphuric and hydrochloric acid, and methane • No free oxygen – a nasty, poisonous, acidic mixture 3) Modern Atmosphere • Modification of earlier atmosphere by life processes • Removal of carbon dioxide and enrichment of free oxygen

  23. The Oxygen Revolution 1)Photosynthetic marine bacteria begin releasing oxygen (O2) into the ocean and the atmosphere by 3 billion years ago Photosynthesizing Cyanobacteria 2) By about 2 billion years ago, sufficient O2 in atmosphere to oxidize (rust) rocks 3) Also by 2 billion years ago, protective ozone (O3) layer built up in atmosphere • Protects Earth’s surface from ultraviolet solar radiation 4) By about 500 million years ago, O2 levels in atmosphere approach today’s levels

  24. Original Sources of Ocean Water • Two Primary Sources • Volcanic Outgassing • Majority Amount of H20 2) Comet Impacts • Minority Amount of H20 Outgassing of Interior Water initially collected from these two sources as part of a thick, dense atmosphere that later condensed and precipitated into surface waters Comet Strikes

  25. Composition of volcanicgases for three volcanoes Water from Outgassing Majority Primary Source = Volcanic Outgassing

  26. Formation of Our Ocean • Three Phase History 1)Initially there was only water vapor in atmosphere– Air and ground surface too hot for liquid 2)Cooling of atmosphere led to condensation and rain– Ground surface still too hot for pooling 3)Further cooling of ground surface finally led to the accumulation of liquid water on surface– Ocean formed by 4 billion years ago 1) 2) 3)

  27. The Twisted Geological Timescale Video Review of Big Bang to Present Day - YouTube

  28. Timeline of Earth’s First Billion Years • First Organisms • End of Bombardment • Oldest Existing Rocks • Formation of Ocean • Formation of Moon • Formation of Earth and Solar System

  29. The Geological Timescale • Key Ideas: • Originally based on relative dating and the use of age-specific fossils • Periods separated by mass extinction events • Numeric ages derived from radiometric analysis of igneous rocks found within the stratigraphic record

  30. The Origin of Life on Earth

  31. Why Life on Earth? The Conditions Venus Mars

  32. Did Life Start in the Ocean? Stromatolites Microfossils 1) Earliest life forms found are fossilized bacteria in rocks dated 3.5 billion years old. 2) Found in both shallow and deep ocean sedimentary rocks. 3) Exposed land surfaces back then were barren and hellish. 4) The ocean was much milder, particularly the deep ocean.

  33. Conditions for Sparking Life • Lab Experiments 1) Simulate early Earth conditions 2) Formed life-giving organic chemicals 3) No actual life created 4) Still an unsolved mystery Comet Impacts? 5) Recent studies point to comet impacts

  34. Most Likely Cradle for Life on Earth? Deep Sea Hydrothermal Vents? • Warm, water-rich environment • Chemical-rich volcanic fluids • Protected from harsh surface

  35. Class Discussion

  36. Review of Study Topics • The Origin of Universe – Energy and Matter • The Origin of the Solar System • Origin of Earth-Moon System • Origin of the Atmosphere • Origin of the Ocean • Origin of the Life

  37. Preparation for Next Meeting Next Meeting Topics 1) Deep Time and The Age of Earth 2) Continental Drift Hypothesis 3) The Plate Tectonic Theory • Homework Assignment: • Read Chapter 2 in Textbook • Study the Instructor’s Website • @ www.geoscirocks.com • Lecture Notes • PowerPoint • ER Videos 5 and 6

  38. Continental Drift Hypothesis Alfred Wegener (1880-1930)

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