Introduction to PLanet

1. Introduction to Planet “Earth”
Dewi Embong Bulan
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2. Oceanography
 Geological Oceanography
 Chemical Oceanography
 Physical Oceanography
 Biological Oceanography
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3. Overview
 70.8% Earth covered by ocean
 Interconnected global or world ocean
 Oceans contain 97.2% of surface water
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Fig. 1.3ab

4. The four principal oceans
Pacific
Atlantic
Indian
Arctic
Plus:
Southern or
Antarctic Ocean
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5. Comparison of elevation and depth
 Average depth 3729 m (12,234 ft)
 Average elevation 840 m (2756 ft)
 Deepest ocean Mariana Trench 11,022 m (36,161 ft)
 Highest continental mountain Mt. Everest 8850 m (29,935 ft)
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6. Fig. 1.3cd
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7. Exe. 01-01
 Name principle oceans on the earth.
 Do you think if “earth” is misnamed for
our planet? Why?
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8. Scientific method
Observations
Hypotheses
Testing and modification of hypotheses
Theory
Probably true versus absolutely true
Science is continually developing
because of new observations
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9. Scientific method
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Fig. 1.9

10. Density
Density is defined as:
Mass of unit divided by Volume of
unit
 = m / V
Example:
A rock has a mass of 5000 Kg
Its volume is 2 m3
 = m / V
 = 5000 Kg / 2 m3
 = 2500 Kg/m3
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11. Density stratification
 Protoearth experiences density stratification
 Density = how heavy something is for its size
 Density stratification causes high density material to sink while
low density material rises
 High density material = rock material and metals
 Low density material = gases
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12. Origin of the Solar System and Earth
Cloud of
gas and
space dust
(nebula)
began to
contract
about 4.6
billion years
ago
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The Nebular Hypothesis

13. Origin of the Solar System and Earth
 Protoplanets were created from the nebula
 Protoearth was initially homogenous:
 Larger in size than today’s Earth
 Had lots of volcanic activity
 No continents or oceans
 No life
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14. Origin of Earth’s atmosphere
Partial melting resulted in outgassing
about 4 billion years ago
Similar to gases emitted from volcanoes
Mainly water vapor
Carbon dioxide, hydrogen
Other gases such as methane and
ammonia
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15. Origin of Earth’s oceans
Water vapor released by outgassing
Condensed as rain
Accumulated in ocean basins
About 4 billion years ago
Ice Comets were also important to
adding water to the Earth system
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16. Fig. 1.17
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17. Ocean salinity
Rain dissolves rocks
Dissolved compounds (ions)
accumulate in ocean basins
Ocean salinity based on balance
between input and output of ions
Ocean salinity nearly constant
over past 4 billion years
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18. Exe. 01-02
 Please describe how our solar system, the atmosphere and ocean were
formed on the earth?
 What is density stratification?
 Why is sea water salty?
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19. Earth’s internal structure
Highest density material at center
(core)
Lowest density material at surface
(crust)
Earth layered
Chemical composition
Physical properties
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20. Chemical composition
Crust
Low-density, mainly silicate
minerals
Mantle
Mainly Fe and Mg silicate minerals
Core
High-density, mainly Fe and Ni
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21. Layered
Earth
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Fig. 1.14

22. Physical properties
Lithosphere
Asthenosphere
Mesosphere
Outer core
Inner core
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23. Physical properties
Lithosphere
Cool, rigid, brittle
Surface to about 100 km (62 miles)
Asthenosphere
Warm, plastic, able to flow
From 100 km to 700 km (430 miles)
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24. Fig. 1.15
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25. Lithosphere
Oceanic crust
Underlies ocean basins
Igneous rock basalt
Average thickness 8 km (5 miles)
Relatively high density
3.0 g/cm3
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26. Lithosphere- Crust and Uppermost
mantle fused together.
Continental crust
Underlies continents
Igneous rock granite
Average thickness 35 km (22 miles)
Lower density
2.7 g/cm3
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27. Asthenosphere
Upper mantle
Plastic—deforms by
flowing
High viscosity—flows
slowly
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28. Exe. 01-03
 In terms of chemical property, how many layers does the
earth have? List them.
 In terms of physical property, how many layers does the
earth have? List them.
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29. Life in oceans
Earliest life forms fossilized
bacteria in rocks about 3.5 billion
years old
Marine rocks
Life originated in oceans?
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30. Stanley Miller’s experiment
 Organic molecules formed by ultraviolet light, electrical spark (lightning),
and mixture of water, carbon dioxide, hydrogen, methane, and ammonia
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31. Fig. 1.18a
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32. Age of Earth
Radiometric age dating
Spontaneous change/decay
Half-life
Earth is about 4.6 billion years old
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33. Geologic time
scale
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Fig. 1.H

34. Exe. 01-04
 How old is the earth? When did life start on the earth? How
do we know these?
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35. Summary
 General Information: earth, oceans
 Scientific Methods
 Origin of Earth, Ocean, Atmosphere
 Internal Structure of Earth
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