Origin of EarthOrigin of Earth’’s Oceans OceanScientific Observations and Explanations on theScientific Observations and Explanations on the

Origin and Evolution of EarthOrigin and Evolution of Earth’’s Oceans Ocean

Introductory OceanographyIntroductory OceanographyRay Rector - Instructor

Preview of TopicsPreview of Topics The Scientific MethodThe Scientific Method Origin of the UniverseOrigin of the Universe –– Forces, Energy, Matter, SpaceForces, Energy, Matter, Space

Origin of the Solar SystemOrigin of the Solar System Origin of EarthOrigin of Earth--Moon SystemMoon System Origin of the Ocean and AtmosphereOrigin of the Ocean and Atmosphere Origin of LifeOrigin of Life The Age of the EarthThe Age of the Earth

The Scientific MethodThe Scientific Method –– Heart of ScienceHeart of Science

Investigation and Application of theInvestigation and Application of theScientific MethodScientific Method

Investigation and Application of theInvestigation and Application of theScientific MethodScientific Method

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THE SCIENTIFIC METHODTHE SCIENTIFIC METHODThe Basic ComponentsThe Basic Components

Empirical Observations

Questions / Problems

Hypotheses / Models

Predictions

Tests / Experiments

Analysis of Results

Draw Conclusions

Reevaluate Hypothesis

Note: Scientific method is NOT a Recipe – it’s a Cyclic Process

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EmpiricalEmpirical Observations: Basis ofObservations: Basis ofAll Scientific Studies and TheoriesAll Scientific Studies and Theories

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EmpiricalEmpirical Observations:Observations: Basis of AllBasis of AllScientific Studies and TheoriesScientific Studies and Theories

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Hypotheses and Scientific TestingHypotheses and Scientific Testing

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ObservationsObservations andandPredictionsPredictions

1) A hypothesis is a proposed explanation, model, or predictionof nature that requires testing (attempt to falsify or confirm).

2) Hypotheses are based on empirical physical evidence (data).

3) Hypotheses must be falsifiable (testable/predictable).

4) Hypotheses can never be proven as an absolute fact.

5) Hypotheses are always open to elimination or modification.

6) A theory is a broad, elegant, set of unifying explanations of aset of otherwise unconnected natural phenomena.

7) A theory is established by the interconnection (framework) ofwell-tested and confirmed hypotheses that are, in turn,supported by an enormous amount of physical evidence.

TestingTestingHypothesesHypothesesandand TheoriesTheories

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Testing Your HypothesisTesting Your Hypothesis

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ScientificScientific PredictionsPredictions

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ScientificScientific ModelingModeling andand PredictingPredicting

Purpose of Modeling:Purpose of Modeling: Understand and predict howparts of the Earth operate and interact with each other

--- Start simple and get more complicated over time

--- Add more and more parameters over time

--- Test computer models with real historic data

---- Develop and refine models to predict future scenarios

A Twisted COSMIC TimescaleA Twisted COSMIC Timescale

The Visible and Invisible UniverseThe Visible and Invisible Universe

13.7 Billion Years of Creation and Destruction13.7 Billion Years of Creation and Destruction

The Basic ComponentsThe Basic Components Expanding SpaceExpanding Space 4 Fundamental Forces4 Fundamental Forces EnergyEnergy -- EMREMR MatterMatter Dark energyDark energy Dark MatterDark Matter

How Much Stuff Is Out There?How Much Stuff Is Out There?

Position in the sky and the extent of the magnificationPosition in the sky and the extent of the magnification

Hubble Deep Field ImageHubble Deep Field Image

Every spotof light is agalaxy!

The Rough Stats:The Rough Stats:1) Size1) Size: 30 x 10: 30 x 1099 cubic light yearscubic light years

1x101x1066 light yrs between galaxieslight yrs between galaxies

2) Matter2) Matter: 100 billion galaxies: 100 billion galaxies 1.6 x 101.6 x 106060 kilogramskilograms@ 1.4 kg per cubic meter@ 1.4 kg per cubic meter

3) Only3) Only 0.0000000000000000000042 %0.0000000000000000000042 %of the universe contains any matterof the universe contains any matter ItIt’’s a SUPER empty place!s a SUPER empty place!

Survey of Elements Found in NatureSurvey of Elements Found in Nature

Cosmic Abundances of Elements

92 Naturally-occurring elements

Mostly Hydrogen and Helium

Lots of Carbon, Nitrogen, Oxygen,Silica, Sulfur, and common metals

BIG BANG TheoryBIG BANG Theory -- 14 Billion Years of Cosmic Evolution14 Billion Years of Cosmic Evolution

The Big BangThe Big BangElementsElements

HydrogenHydrogen HeliumHelium

?

GalaxiesGalaxies –– Gigantic Star ClustersGigantic Star Clusters

Galaxies areGalaxies are ““island universesisland universes”” where starswhere starsare born, live and dieare born, live and die

Gravity is the controlling force on galaxyGravity is the controlling force on galaxyformation and evolutionformation and evolution

The Universe contains roughly 1 to 2The Universe contains roughly 1 to 2trillion galaxiestrillion galaxies

Typical galaxy contains 100 billion starsTypical galaxy contains 100 billion stars A typical star located in a galaxy is muchA typical star located in a galaxy is much

like our Sunlike our Sun Stars generate new elements duringStars generate new elements during

fusion and explosive nova eventsfusion and explosive nova events All elements except for the very light onesAll elements except for the very light ones

can only form inside starscan only form inside stars Our galaxyOur galaxy –– the Milky Waythe Milky Way –– looks verylooks very

much like our neighbormuch like our neighbor –– the Andromedathe Andromedagalaxy.galaxy.

Andromeda Galaxy

Trillions of Galaxies!!!

Key Points:Key Points:

Our Very Own Island UniverseOur Very Own Island Universe

Milky Way Galaxy is 100Milky Way Galaxy is 100million light in diametermillion light in diameter

Our galaxy containsOur galaxy containsroughly 400 billion starsroughly 400 billion stars

Sun is a very typical starSun is a very typical starlocated in one of the armslocated in one of the armsof the Milky Way Galaxyof the Milky Way Galaxy

Other planetary systemsOther planetary systemshave been found in ourhave been found in ourgalaxygalaxy

We arehere

Milky Way GalaxyMilky Way Galaxy

NebulaNebula –– Star NurseriesStar Nurseries Nebula are regions of denseNebula are regions of dense

hot gases, stellar debris, andhot gases, stellar debris, andvery young starsvery young stars

New stars and planetaryNew stars and planetarysystems form from the bothsystems form from the bothprimordial matter and theprimordial matter and theremnants of exploded starsremnants of exploded starswithin nebulawithin nebula

Our solar system most likelyOur solar system most likelyformed in a nebula much likeformed in a nebula much likethis onethis one

Condensation Theory forCondensation Theory forstar and planet formationstar and planet formationCarina Nebula

Observed Stellar Systems in the MakingObserved Stellar Systems in the Making

The Trifid Nebula

Observations of NewlyObservations of NewlyForming Stars Within aForming Stars Within aNebula CloudNebula Cloud

Condensation TheoryCondensation Theory

Stellar FusionStellar Fusion –– The Element FactoryThe Element Factory

1) Normal Star= Helium

3) Red Supergiant Star= Neon through Iron

2) Red Giant Star= Carbon

The Fusion Process

Note: Stellar fusion processes cangenerate light to medium weightelements: from Helium (He) all theway up to Iron (Fe).

ThreeThree--Stage Star EvolutionStage Star Evolution

SupernovaSupernova –– Heavy Element FactoryHeavy Element Factory

SupernovaProcess

Collapse of Red SupergiantsTycho-supernova

A Stellar ImplosionA Stellar Implosion––Explosion EventExplosion Event

Note: Supernova events generate medium-to heavyweight elements: from Iron (Fe) allthe way up to Uranium (U)

Planet Formation:Planet Formation:The NebulaThe Nebula

Condensation TheoryCondensation Theory

Animation1

Animation2

We arehere Our Solar SystemOur Solar System

4 Inner Planets

Mercury

Venus

Earth

Mars

4 Outer Planets

Jupiter

Saturn

Uranus

NeptuneWhatabout

poor littlePluto?

We arehere

Our Solar SystemOur Solar System

Poor littlePluto

demoted toDwarfPlanet

Origin of the MoonOrigin of the MoonMultiple Theories

Twin Planet Theory

Moon Capture Theory

Earth-Birthed Theory

Giant Impact Theory

Most Likely Origin of the MoonGiant Impact Theory

Impact Sequence of Earthand Mars-size Body

Density Differentiation of Young EarthDensity Differentiation of Young Earth

Proto-earth was homogenous

Proto-earth underwent completemelting due to accretion energy andradioactive decay

Heaviest elements sank down toform core – mainly iron and nickel

Medium weight elements formedmantle and crust– mainly silicateminerals

Lighter elements floated up to formocean and atmosphere

EarlyEarly--stage Differentiation Modelstage Differentiation Model

Terrestrial Planet ComparisonTerrestrial Planet Comparison

Earth and Venus very similar in overall size and composition

Mars much smaller, with cooler interior

Each planet has unique crustal characteristics, in terms oftemperature, crustal composition and processes,atmospheres, and water.

Composition and Structure of EarthComposition and Structure of Earth

Five ChemicallyDistinct Layers

Eight PhysicallyDistinct Layers

Formation of the EarthFormation of the Earth’’s Oceans Oceanand Atmosphereand Atmosphere

1) The Origins of Earth’sAtmosphere and Ocean areClosely Tied Together

2) The Composition of theAtmosphere Has GreatlyChanged Over the LastFour Billion Years

3) The Composition of OceanInitially Changed Over theFirst Billion Years But HasSince Remained Stable

Evolution of EarthEvolution of Earth’’s Atmospheres AtmosphereThree StagesThree Stages1) 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 andhydrochloric 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

Terrestrial Atmosphere ComparisonTerrestrial Atmosphere Comparison

Venus MarsEarth

Venus atmospheresuper thick, hotand nearly all CO2

Mars atmospheresuper thin, cold andnearly all CO2

The OxygenThe OxygenRevolutionRevolution

1)1) Photosynthetic marine bacteriaPhotosynthetic marine bacteriabegin releasing oxygen (Obegin releasing oxygen (O22) into) intothe ocean and the atmospherethe ocean and the atmosphereby 3 billion years agoby 3 billion years ago

2) By about 2 billion years ago, sufficient2) By about 2 billion years ago, sufficientOO22 in atmosphere to oxidize (rust) rocksin atmosphere to oxidize (rust) rocks

Protects EarthProtects Earth’’s surface from ultraviolet solar radiations surface from ultraviolet solar radiation

PhotosynthesizingPhotosynthesizingCyanobacteriaCyanobacteria

3) Also by 2 billion years ago, protective ozone (O3) Also by 2 billion years ago, protective ozone (O33) layer) layerbuilt up in atmospherebuilt up in atmosphere

4) By about 500 million years ago, O4) By about 500 million years ago, O22 levels in atmospherelevels in atmosphereapproach todayapproach today’’s levelss levels

Original Sources of Ocean WaterOriginal Sources of Ocean Water

Two Primary SourcesTwo Primary Sources1) Volcanic Outgassing Majority? of H20

2) Comet Impacts Minority? Amount

Outgassing of Interior

Comet Strikes

Water fromWater from OutgassingOutgassingMajority Primary Source = Volcanic Outgassing

Composition ofvolcanicgases for threevolcanoes

Terrestrial Atmosphere ComparisonTerrestrial Atmosphere Comparison

Formation of Our OceanFormation of Our OceanThree Phase HistoryThree Phase History

1) Initially there was only waterInitially there was only watervapor in atmospherevapor in atmosphere – Air andground surface too hot for liquid

2) Cooling of atmosphere led toCooling of atmosphere led tocondensation and raincondensation and rain – Groundsurface still too hot for pooling

3) Further cooling of groundFurther cooling of groundsurface finally led to thesurface finally led to theaccumulation of liquid water onaccumulation of liquid water onsurfacesurface – Ocean formed by 4 billionyears ago

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2)

3)

Timeline of EarthTimeline of Earth’’s First Billion Yearss First Billion Years

First Organisms

End of Bombardment

Oldest Existing Rocks

Formation of Ocean

Formation of Moon

Formation of Earthand Solar System

You Tube Video

The Origin of Life on EarthThe Origin of Life on Earth

Why Life on Earth?Why Life on Earth?

MarsVenus

Did Life StartDid Life Startin the Ocean?in the Ocean?

1) Earliest life forms found are1) Earliest life forms found arefossilized bacteria in rocks datedfossilized bacteria in rocks dated3.5 billion years old.3.5 billion years old.

2) Found in both shallow and2) Found in both shallow anddeep ocean sedimentary rocks.deep ocean sedimentary rocks.

3) Exposed land surfaces back3) Exposed land surfaces backthen were barren and hellish.then were barren and hellish.

4) The ocean was much milder,4) The ocean was much milder,particularly the deep ocean.particularly the deep ocean.

Stromatolites Microfossils

Conditions for Sparking LifeConditions for Sparking LifeLab ExperimentsLab Experiments

1) Simulate early Earth conditions

2) Formed life-giving organic chemicals

3) No actual life created

4) Still an unsolved mystery

Comet Impacts?Comet Impacts?

5) Recent studies point to comet impacts

Most Likely Cradle for Life on Earth?Most Likely Cradle for Life on Earth?

Deep Sea Hydrothermal Vents?Deep Sea Hydrothermal Vents?

Warm, water-rich environment

Chemical-rich volcanic fluids

Protected from harsh surface

Life and the Geological TimescaleLife and the Geological TimescaleKey Ideas:Key Ideas: Originally based onOriginally based onrelative dating and userelative dating and useof ageof age--specific fossilsspecific fossils

Periods separatedPeriods separatedby mass extinctionsby mass extinctions

Numeric ages fromNumeric ages fromradiometric analysis ofradiometric analysis ofigneous rocks foundigneous rocks foundbetween fossil layersbetween fossil layers

First life forms occurFirst life forms occur3.5 billions years ago3.5 billions years ago

MultiMulti--cellular marinecellular marinelife established 600life established 600million years agomillion years ago You Tube Video

The Twisted Geological TimescaleThe Twisted Geological Timescale

Video Review of Big Bang to Present Day - YouTube

Class DiscussionClass Discussion

Review of Study TopicsReview of Study Topics

Origin of UniverseOrigin of Universe –– Forces, Energy, Matter, SpaceForces, Energy, Matter, Space

Origin of the Solar SystemOrigin of the Solar System Origin of EarthOrigin of Earth--Moon SystemMoon System Origin of the AtmosphereOrigin of the Atmosphere Origin of the OceanOrigin of the Ocean Origin of the LifeOrigin of the Life

Preparation for Next MeetingPreparation for Next MeetingNext Meeting TopicsNext Meeting Topics1) Age of Earth1) Age of Earth2) Earth Physiology2) Earth Physiology3) Continental Drift Hypothesis3) Continental Drift Hypothesis4) The Plate Tectonic Theory4) The Plate Tectonic Theory

Homework Assignment:Homework Assignment: Read Chapter 2 in Textbook Study the Instructor’s Website

@ www.oceansci.com Lecture Notes PowerPoint EV Videos 3 and 4

Continental Drift HypothesisContinental Drift Hypothesis

Alfred Wegener(1880-1930)