Introduction to the Earth
Introduction to the Earth
Neptune
Uranus
Mars
Saturn
Jupiter
Mercury
Venus
The Solar System
Introduction to the Earth
•The Environmental Spheres
•The Size and Shape of the Earth
•The Geographic Grid
The Environmental Spheres
Lithosphere - describes the solid inorganic portion of the
Earth (composed of rocks, minerals and elements). It can
be regarded as the outer surface and interior of the solid
Earth.
The Environmental Spheres
Atmosphere - is the vast gaseous envelope of air that
surrounds the Earth. Its boundaries are not easily defined.
The atmosphere contains a complex system of gases and
suspended particles that behave in many ways like fluids.
Many of its constituents are derived from the Earth by way
of chemical and biochemical reactions.
The Environmental Spheres
Hydrosphere - describes the waters of the Earth (see the
hydrologic cycle). Water exists on the Earth in various
stores, including the atmosphere, oceans, lakes, rivers,
soils, glaciers, and groundwater. Water moves from one
store to another by way of: evaporation, condensation,
runoff, precipitation, infiltration and groundwater flow.
The Environmental Spheres
Biosphere - consists of all living things, plant and animal.
This zone is characterized by life in profusion, diversity,
and ingenious complexity. Cycling of matter in this sphere
involves not only metabolic reactions in organisms, but
also many abiotic chemical reactions.
All of these spheres are interrelated by dynamic
interactions (biogeochemical cycling)
The Size and Shape of the Earth
Pythagorus (ca. 580 - 500 B.C., Greek) - first to note
spherical character of the earth. This principle was widely
accepted by 1st Century A.D. Columbus, for example, was
well aware of sphericity of earth.
How to proof sphericity?
The Size and Shape of the Earth
How to proof sphericity?
Pythagorous:
Ships “sinking” below the horizon as they sail
into distance (Pythagorous).
Curved shadow cast by earth during eclipse
(Pythagorous).
Today:
•Aerial/Space Photos
Sunsets are gradual
Navigation, which uses spherical trigonometry,
works.
 North Star moves with latitude.
The Size and Shape of the Earth
However, Pythagorous assumed spherical perfection. Sir
Isaac Newton (1687) reasoned that sphere not possible
since earth rotation is maximized at the equator and this
should produce a ‘bulge.’ He called earth an oblate
spheroid (think of spinning water balloon; Jupiter is eggshaped enough to be noticeable through inexpensive
telescope).
N
7927
miles
7900
miles
The Size and Shape of the Earth
Earth Dimensions
diameter: 8,000 miles (12,900
km)
circumference = ¶ d or 3.14 x
8,000 = 25,000 miles
Geoid - conceptualizes earth
w/o imperfections.
In fact, if radius of earth was 30
story building, Mt. Everest would
be only a single brick in height.
The Geographic Grid
Latitude - angular measurement of distance north or
south of the Equator.
Range: 0 - 90
degrees N or S
1o latitude =
approx. 69 miles
(25,000 mi. /360o).
Important Parallels
Parallel - Imaginary lines that connect points of equal
latitude.
These seven
parallels
represent special
points where the
Sun’s rays strike
the earth.
The Geographic Grid
Longitude the angular measurement of distance
east or west of the Prime Meridian.
Maximum value
reached at
International Date
Line - 180o
Range: 0o 180o E or W
Length of a Degree of
Longitude
East-west width of 1O longitude for selected
western North American cities:
San Diego (32.5 N) = 57 miles; San Francisco
(38 N) = 54 miles; Seattle (48 N) = 46 miles;
Anchorage (60 N) = 35 miles
Degrees, Minutes, Seconds
Los Angeles County: 34o N, 118o W
Each degree is divided in 60 minutes(‘), thus we
can locate Torrance at: 33o 53’ N, 118o 19’ W
Each minute is further divided into 60 seconds(‘’),
thus we locate El Camino College at:
33o 53’ 06” N, 118o 19’ 38” W
At this point we are accurate to within 100 ft2.