1. © 2016 Cengage Learning. All Rights Reserved. 1 Oceanography, An Invitation to Marine Science | 9e Tom Garrison The Origin of the Ocean

2. © 2016 Cengage Learning. All Rights Reserved. Science is a systematic process of asking questions about the observable world by gathering and then studying information The universe’s observable mass consists mostly of hydrogen atoms –The heavy elements we see around us were constructed in stars Earth is density stratified –Earth’s first solid surface formed about 4.6 billion years ago Key Concepts

3. © 2016 Cengage Learning. All Rights Reserved. Life probably originated in the ocean shortly after it formed Water, even liquid water, appears to be present in other places in our solar system Key Concepts (cont’d.)

4. © 2016 Cengage Learning. All Rights Reserved. Oceanography – story of the ocean Liquid water can exist on Earth Ocean – body of saline water Single world ocean – Earth’s oceans are connected 1.1 Earth Is an Ocean World

5. © 2016 Cengage Learning. All Rights Reserved. Science – systematic process of asking questions, gathering and interpreting data Hypothesis – speculation that can be tested Experiment – test that simplifies observation in nature Theory – statement that explains observations Scientific method – process 1.2 Marine Scientists Use the Logic of Science to Study the Ocean

6. © 2016 Cengage Learning. All Rights Reserved. A Logical Series of Steps Can Represent the Procedure of Science

7. © 2016 Cengage Learning. All Rights Reserved. The big bang occurred about 13.7 billion years ago Stars formed early in the history of the universe –About a million years after the big bang temperatures were cool enough for atoms –About a billion years after the big bang stars and galaxies could form 1.3 Stars Form Seas

8. © 2016 Cengage Learning. All Rights Reserved. Stars and planets are contained within galaxies –We live in the Milky Way galaxy –Stars – spheres of incandescent gases –Star and family of planets – solar system Stars make heavy elements from lighter ones: –By fusing hydrogen into helium –From dying stars – supernovae Stars and Galaxies

9. © 2016 Cengage Learning. All Rights Reserved. The Dispersion of Heavy Elements

10. © 2016 Cengage Learning. All Rights Reserved. Solar systems form by accretion –Particles clump together to form larger masses –Heavier elements are concentrated closer to the sun –Lighter elements make up the outer planets Solar Systems

11. © 2016 Cengage Learning. All Rights Reserved. Density stratification – gravity pulls heavier elements towards the center of an object, lighter elements rise to the outside The first surface formed about 4.6 billion years ago Earth’s moon formed from a collision of Earth and another planetary body –About 4.4 billion years ago 1.4 Earth, Ocean, and Atmosphere Accumulated in Layers Sorted by Density

12. © 2016 Cengage Learning. All Rights Reserved. A Representation of the Formation of Earth

13. © 2016 Cengage Learning. All Rights Reserved. Stepped Art Iron Lighter matter and silicates

14. © 2016 Cengage Learning. All Rights Reserved. Earth’s first atmosphere was stripped away by radiation from the sun Vapors came from inside the planet – outgassing Water vapor existed in the atmosphere –Eventually cooled to form clouds and precipitated to the surface Early ocean and atmosphere different from today Earth’s First Atmosphere

15. © 2016 Cengage Learning. All Rights Reserved. Biosynthesis – formation of living organisms from simple organic building blocks –Unlikely to occur today –Conditions on the young Earth were sufficiently different Oldest fossils 3.4 to 3.5 billion years old –Remains of bacteria-like organisms 1.5 Life Probably Originated in the Ocean

16. © 2016 Cengage Learning. All Rights Reserved. One of the Oldest Fossils Ever Discovered

17. © 2016 Cengage Learning. All Rights Reserved. The sun will begin to die in around 5 billion years –Red giant phase will engulf the inner planets in solar atmosphere –Earth will be recycled 1.6 What Will Be Earth’s Future?

18. © 2016 Cengage Learning. All Rights Reserved. Water is not scarce in the solar system Jupiter and Mars contain ice Liquid water exists on Jupiter’s moons, Europa and Ganymede, underneath crusts of ice Liquid water could exist on Saturn’s moon Enceladus 1.7 Are There Other Ocean Worlds?

19. © 2016 Cengage Learning. All Rights Reserved. Mars may have had an ocean in the distant past –Evidence for water erosion on the surface –Water could have frozen beneath the surface as the planet lost its atmosphere Saturn’s moon, Titan, has a liquid ocean of hydrocarbons Water could exist on extrasolar planets Is There Evidence of Water on Other Planets?

20. © 2016 Cengage Learning. All Rights Reserved. Evidence of a Once-Wet Mars

21. © 2016 Cengage Learning. All Rights Reserved. We study our planet using the scientific method Atoms that make up Earth and the solar system were formed in stars Earth formed from accretion 4.6 billion years ago and became density stratified Life probably originated in the ocean No other planet in the solar system has a liquid ocean on the surface Chapter In Perspective

22. © 2016 Cengage Learning. All Rights Reserved. Could life have formed on other planets in our solar system? If so, would life on these planets resemble life on Earth? Some Questions from Students