The Water Planet

An Introduction to the World’s Oceans

Chap. Two - 8th Ed.

Chapter Two Highlights

Origin of our universe & solar system

GeologicTime Shape & orientation of

the Earth relative to the Sun

Mapping and location systems

Navigation The Water Cycle

Beginnings Origin of the universe

– Big Bang model

– Stars, galaxies, and clusters

– Wilkinson Microwave Anisotropy Probe - 380,000 years post BB

– Hubble Space Telescope (HST)

Origin of our solar system

– Collapse of a rotating interstellar cloud

– Accretion to form planets

Earth OriginsEarth Origins Big Bang !!!!Big Bang !!!!

– 13 bya 13 bya

– extremely hotextremely hot

– subsequent formation of ~100 million subsequent formation of ~100 million

galaxies with ~100-200 million stars galaxies with ~100-200 million stars

eacheach

– Milky Way is our Milky Way is our spiralspiral galaxy galaxy

( ( galaktosgalaktos = milk ) = milk )

A spiral galaxy structurally similar to the Milky Way Galaxy. 56,000 light years in diameter and 62 million years away.

A spiral galaxy structurally similar to the Milky Way Galaxy. 56,000 light years in diameter and 62 million years away.

Earth OriginsEarth Origins Planetary Accretion TheoryPlanetary Accretion Theory

– 5 bya 5 bya

– solar nebula (swirling dust cloud) from solar nebula (swirling dust cloud) from

a a supernovasupernova

• ~75% H, 23% He, 2% other stuff ~75% H, 23% He, 2% other stuff

– most material drawn to center to form most material drawn to center to form

protosun protosun

– rest rest accretesaccretes to form to form planetsplanets

1 light year ~ 9.5 X 1012

kms.

1 light year ~ 9.5 X 1012

kms.

Origin of the Solar System and Earth

Cloud of gas and space dust (nebula) began to contract about 4.53 billion years ago.

The Nebular Hypothesis

Conceptualization of planetary accretion.

Conceptualization of planetary accretion.

Hubble Space Telescope image of solar nebula similar in size to ours. Obscuring dust cloud across center.

Hubble Space Telescope image of solar nebula similar in size to ours. Obscuring dust cloud across center.

First image of a “possible” planet outside of our solar system.

First image of a “possible” planet outside of our solar system.

Water in the S0lar System

Extraterrestrial oceans – Liquid oceans on Jupiter’s moons,

Europa and Callisto Early planet Earth

– Separation of dense and lighter compounds through repeated melting and solidifying layered system, ocean, and atmosphere

– No free oxygen until photosynthetic organisms evolved

Mars shows erosional and depositional features that suggest the presence of running water in the past.

Mars shows erosional and depositional features that suggest the presence of running water in the past.

Origin of the Oceans Age of Earth: approximately 4 billion years

Water from interior of Earth

– Mantle

– Gas that escape volcanoes is 70% water vapor

– 4 billion years at current rate 100 times the volume of the oceans

Water from outer space

– 10 million comets enter the atmosphere each year

– Layer of water 0.0025 mm deep added each year

– 4 billion years at current rate 2 to 3 times the volume of the oceans

OutgassingOutgassing

Box Fig. 1, pg. 30

Box Fig. 2, pg. 31

Comets

Comets

Age and Time

Age of Earth – History of estimates

• Bible 10/23/4004 B.C. , cooling time, rate of addition of salt in oceans by rivers, radiometric dating

– Radiometric dating 4.5-4.6 billion years Geologic time

– Eons, eras, periods, epochs

– Important events Natural time periods

– Time required for Earth to complete one orbit around the Sun

– Length of day and seasons– Lunar month– Solar day– Sidereal day

A Timeline Of Earth’s History

Table 2.2 bottom

Table 2.2 top

Fig. 2.6

Shape of Earth

Gravity – Earth is nearly spherical

Spin – Earth bulges at equator

Distribution of continents– Slightly pear shaped

Topographic relief – Minor compared to planet’s size

Fig. 2.7

Location Systems Latitude and longitude

– Latitudes (or parallels) are parallel to the equator

– Longitudes (or meridians) are formed at right angles to the latitude lines

• Prime meridian and international date line

– Great Circle– Nautical mile (1 minute of arc at the

equator) Chart projections

– Distorted images of Earth’s curved surface

– Projection types: cylindric, conic, and tangent

Fig. 2.8

Fig. 2.9

Fig. 2.10

Fig. 2.11

Fig. 2.12

Fig. 2.13

Fig. 2.14

Fig. 2.15

Location Systems

Measuring latitude

– North Star, Polaris Longitude and time

– Use of clocks to record the time the Sun is at its zenith

– Greenwich Mean Time (GMT) or Universal Time

Fig. 2.16

Fig. 2.17

Modern Navigational Techniques

Radar (radio detecting and ranging)

Loran (long-range navigation) Satellite navigation system Global Positioning System (GPS) Shipboard computers

– Electronic atlas• Surface charts

• Bathymetry

• Continuous tracking of ship’s position

Fig. 2.18a

Fig. 2.18b

Earth: The Water Planet

Water on Earth’s surface– Effect of seasons

– Effects length of day

– 71% of Earth’s surface is covered by water, while 29% of the surface area is land

Hydrologic cycle– Evaporation, transpiration, and

sublimation

– Precipitation, rain, and snow

Fig. 2.19

Earth: The Water Planet

Reservoirs and residence time– Large reservoirs long residence time

– Small reservoirs short residence time

Distribution of land and water – Northern Hemisphere (land)

– Southern Hemisphere (water) Oceans Hypsographic curve

Fig. 2.20

Table 2.3

Geography of the oceans

Earth’s oceans:

Cover 70.8% of Earth’s surface

Are interconnected (“world ocean”)

Have huge size and volume (as a

reservoir, contain 97% of Earth’s water)

Fig. 2.21

Fig. 2.22

Fig. 2.23

The four principal oceans

Fig. 2.24

The End