Coming in Movie

Geography: Earth in Space & Place...

 

Basic Definition of Geography: the location and distribution of features at/near the Earth’s surface.

 

o   Location: the place of something; absolute (exact) and/or relative (in relation to something else)

o   Distribution: spatiality of phenomena (how things are arranged--what is where and why)

o   Features: Human (cultural) and Physical (natural)

 

So...Geography necessarily overlaps with many disciplines!!

 

Two key elements make Geography unique among disciplines: 1) focus on place, and 2) focus on space.


I. Systems Theory (Earth sustained by a series of linked systems)

 

Definition of a System: 

An assemblage of interrelated parts that work together by way of some driving process(es)

o   Exchanges of energy and/or matter via input and output processes

o   Operating together as a whole; the sum of many interacting parts

o   Open systems

o   Inputs and outputs enter and leave the system

o   Closed systems

o   Inputs loop around continually in the system

o   System feedback

o   System equilibrium

Example of a Monday Night Football Game:

o   Input of Energy Sources: profile, prestige, motivation

o   Input of Material: food, people

o   Outputs: press stories, tear up the field, radio broadcast, school reputation, money, injuries

o   Subsystems: officials, teams, coaches, traffic control, vendors, home crowd, pedocabbies...

 


II. Earth as a System

 

MoonRise

 

Earth as an Oasis:

 

Taken for granted now

o   Holiday season of 1968 and Apollo 8 mission looking back at the earth from the moon

o   Boost to environmental movement view that we need to protect the earth.  Prior to the environmental movement, dumping trash and industrial waste was accepted by the general population

o   Perception so common now that view of Earth from Mars was no big deal for those under 35

Major Subsystems:

 

Animation, Diagram

 

Case’s Diagram...

o   Atmosphere: realm of air (Gr. atmo)

o   Hydrosphere: realm of water (Gr. hydro)

o   Lithosphere: realm of solid earth (Gr. litho)

o   Biosphere: realm of life (Gr. bio)

o   Pedosphere: realm of soil (L., from ped, soil)

Sources of Energy & Matter

o   Energy – from solar radiation (insolation) that keeps earth warm

o   Energyfrom the spin of the earth (correct spin of earth, looking down at the north pole) that keeps atmosphere in motion

o   Energy – occasional asteroid impacts that contributed to dinosaur extinction, generated tremendous energy.  But we get substantial energy from asteroid and other small object impacts on a regular basis (like Meteor Crater)

o   Energy – from inside earth to produce elevation (relief) that gives energy to running water [other views: 1 - 2] (and gives us energy by hydroelectric power; third-largest dam: Itaipu, Paraguay)

o   Matter – chemicals in all subsystems, for example Fe

o   Matter – from extraterrestrial impacts (water?)

Transfer of energy and matter by earth-surface processes

 

Organization of class...

o   Earth’s Place...parameters, measures, technology

o   Lithosphere (EX)

o   Hydrosphere (EX)

o   Pedosphere

o   Atmosphere (EX)

o   Different Physical Landscapes

o   Biosphere (EX)

Transfer of energy and matter produces regional patterns

What can you give as examples?

o   Case 1

o   Case 2

o   Case 3

 


III. Why Earth is unique in the Solar System (are other planets jealous?)

 

A. Liquid Water Allows Chemical Reactions

 

Sidebar Speculation about Mars:

o   Liquid used to exist on Mars, and there is evidence of recent water on Mars, or old water deposits (that might relate to snow melt), and new evidence of glaciers underneath its surface!

o   There is also a lot of speculation about life in the ice on Mars

o   Rock coatings may provide evidence of life in the new Lander missions

 

**We know Earth is the place where life exists because liquid water allows chemical reactions**

 

B. Great Atmosphere

1. Mass of Earth Holds Right Composition

o   Too little mass gives you Mars, not dense enough and mostly carbon dioxide

o   Too much mass gives you Gas Giants keeping hydrogen, and hence ammonia and methane

o   Abundance of oxygen allowed us (placental mammals) to evolve

2. Lethal Radiation Stopped:  example of Ozone Shield

3. Not too cold/not too hot

o   as opposed to tremendous diurnal variation on our moon, or

o   as opposed to extreme heat of Venus’ runaway greenhouse effect

o   (are you bored or paying attention?)

4. Water exists in three phases: solid, liquid, gas

o   Also sublimation between solid and gas

o   That change seasonally and regionally

o   Giving and releasing energy (imagine a ladder...of potential energy)

o   So when melting occurs, is energy released or adsorbed?

o   Put your finger in your mouth and blow: is energy released or adsorbed?

5. Pressure is perfect

6. Help protect us from incoming space debris (certainly not all, but smaller stuff)

 

auroraaustralis_ANIMGIF
 

C. Earth’s Magnetic Field

o   Magnetosphere deflects harsh solar wind, including dramatic solar storms that disturb satellites (October 03)

o   When you see such features as the Northern Lights (or Southern Lights; Space Station view) -- think about how your magnetic field is protecting you

o   We may be heading into a period of greater solar activity (article, pdf)

 

Sidebar on what would happen if we lost our magnetosphere?

o   As magnetospheres go, Earth is not special: Mercury, Jupiter, Saturn, Uranus, and Neptune all have magnetospheres

o   Mars is the real mystery: it is pretty cold and is quite like Earth in many ways...so why no magnetosphere?

o   Mars lost its overall magnetism, when the molten iron in the core solidified

o   Mars may have lost life and its atmosphere when the magnetosphere no longer protected Mars a solar wind that stripped its atmosphere!

 

D. Earth’s Spin (not this way!)

o   Gives us the CORIOLIS EFFECT: Horizontal deflection of fluid that occurs when a body rotates (conservation of angular momentum)

o   Gives us night and day

o   If too fast, lots of storms, like Jupiter where storms are ferocious – especially away from equator!

o   If too slow, no weather, like Mercury

E. Earth’s Position

o   Some believe that an Earth-sized planet would break apart if it was too close to a gas giant. So we are lucky to be surrounded by smaller planets

F. Biosphere - are we alone?

 

Do you believe in extraterrestrial life

You see the idea everywhere

NASA VIEW has changed

Gaia hypothesis

o   James Lovelock created concept of GAIA (named after Greek Goddess of Earth), that the earth is like an organism that is self-regulating and keeps itself in a constant state (not an experiment of mice)

o   Example: Faint Sun Hypothesis

o   Example: Ozone layer is produced by positive feedback & then equilibrium

o   The big question: how can you/we contribute to keeping Earth a sustainabile system? (Serious page article: click here)

 

Summary: Earth = the “Goldilocks” planet (it’s “just right” for life). It has an amazing set of systems that all work together to maintain and preserve life as we know it.

 


 

IV. Solar Radiation (intro movie)
 

A. Solar Furnace

o   Fusion drives solar energy


intro_anim_solar_fusion

o   Very little reaches the Earth

 

B. Characteristics of Solar Output:

o   Electromagnetic Spectrum (movie 1, movie 2)

o   From elementary school... expand to general idea

o   Simple; interactive

o   Sometimes confused about what is a wavelength

o   Shorter than visible

o   Infrared: near infrared (solar reflectance) and thermal (man, old faithful - movie; Hollywood)

o   Longest: radio and microwave

o   Focus for this class is difference between short and long wavelength radiation

 

Nuts and bolts of long and short wave radiation

 

C. What’s the point?

o   Solar Energy!!! (“Insolation”: INcoming SOLar radiATION)

o   Reaches the Earth in the form of radiant energy, and makes up 99.987% of the energy received by the Earth

o   So...understanding how solar energy varies is important to this class, your grade, where you live, where you may want to vacation or explore, and whether you can answer that age old question of why we have seasons!

 


 

V. Earth’s Dimensions & Spatial References

 

A. Earth’s Size & Shape

o   “3rd Rock from the Sun”

o   5th largest diameter (~8,000 miles [12,900 km])

o   Dimensions; an imperfect sphere (geoid)

o   Measuring the Earth (247 BCE!)

o   Earth’s maximum relief

B. Spatial References on Earth

o   Two important reference points

o   Geographic grid; network of intersecting lines (coordinates); “Cartesian”

o   Can be divided into great and small circles (ex. 1; ex. 2)

o   Lines of latitude (“parallels”) [ex. 1; ex. 2)

o   Latitudinal Zones (simple; complex)

o   Lines of longitude (“meridians”)

o   Put them together...

 


 

VI. Earth’s Orbit: Parameters, Tilt & Seasonality

A. Orbital Parameters

1.  Revolution

o   Complete circling of the sun

o   On the Plane of the Ecliptic...

o   You knew this from Hollywood!

o   365 and 1/4 days (approximately)

o   Orbit is slightly elliptical

o   Perihelion (closest/January): 91.5 million miles

o   Aphelion (farthest/July): 94.5 million miles

o   So...tell me why its summer in July?

o   And, how–WHY–does the earth revolve around the sun? [Newtonian old-school vs. Relativism quantum-school]

2.  Rotation

o   Not a perfect sphere that rotates

o   About 24 hours (23 hours & 56 minutes - unless you are ready to be the source of a joke... )

o   “Rising” and “setting” of the sun (does the sun actual “rise” or “set”?)

o   Counterclockwise rotation when looking down at north pole or from outer space (clockwise when looking from south pole)

o   Responsible for Coriolis Effect

o   Helps us keep time:

o   Old methods: sundial; water or wind clocks

o   New methods: Prime Meridian helped create Time Zones...(GMT vs. UTC)

o   15 degree longitude increments

o   US time zones


So what’s the difference again?

 

Sidebar on Earth’s Moon

 

o   Moon rotates in sync with the Earth

o   Experiences “libration“ because tidally locked to Earth

o   There is no “dark side of the moon” (apologies to Pink Floyd)

o   We only see about 59% of Moon’s surface at any one time (larger view)!

 

3. Tilt (Obliquity) of the Axis

o   Axis tilted 23.5 degrees from the plane of the ecliptic:

o   Axis and tilt is always parallel to itself no matter where it is in the orbit (axis currently points to North Star—Polaris—but shifting...)

o   Mars has variation in obliquity also

 

4. Earth’s Orbit changes at timescale of thousands of years:

o   Eccentricity

o   Precession (movie)

o   May also affect your astrological sign—depending on if you follow the Tropical Zodiac (or “Western”, synced with seasons) or the Sidereal Zodiac (or “Eastern”, synced with constellations)

o   Time articles discussing those for the change and those against the change

o   CNN article discussing overall astrological concept

o   Obliquity (animation) (has also changed over even longer time scales!)

 

And these likely caused glacial-interglacial fluctuations by changing location and amount of solar radiation...

**More on these parameters’ interaction and cycles when we get to the climate section, but here’s a primer**

 

B. Importance of Earth’s Tilt (other than a liberal plot; here’s a more detailed explanation)
 

1. The key latitudes you must know to understand seasons...

2. Introductory movie emphasizing length of day; one key to seasons

3. Introductory movie emphasizing sun angle; the other key to seasons (alternative movie)

4. Closer look at solstice and equinox as they go through the seasons

o   Our Summer Solstice: June 21 or 22 (sometimes 20th or 23rd)

o   Northern hemisphere toward the sun

o   Tropic of Cancer - 23.5 degrees North - overhead sun

o   Arctic Circle @ 66.5 degrees North - 24 hours of daylight (sun hits horizon at midnight!)

o   Antarctic Circle@ 66.5 degrees South - 24 hours night at and to the south

o   From outer space – just night allows you to see aurora australis

o   Winter Solstice: December 21 or 22 (sometimes 20th or 23rd)

o   Southern Hemisphere toward the sun

o   Tropic of Capricorn - 23.5 degrees South - overhead sun

o   Antarctic Circle @ 66.5 degrees South - 24 hour daylight

o   Arctic Circle @ 66.5 degrees North - 24 hour night

o   Where could this photo be taken?

o   Equinoxes: March 20 or 21 (sometimes 22nd or 23rd) and September 21 or 22 (sometimes 20th or 23rd)

o   Overhead sun at the equator

o   Equinox means equal days and equal nights (not other weird ideas) - same on both sides of the orbit (more detail on equal days)

o   But lower angles as you go poleward

 

EMPHASIZE AGAIN

 

Seasons are MAINLY created by earth’s tilt which varies incoming solar radiation (insolation). And that’s determined by:

o   Solar elevation (sun angle)
 and

o   Length of Day

 

And these both depend on: Latitude and Time of Year

 

Sooooo: How would one of the nation’s “most prestigious” universities’ graduates, faculty, and alumni answer the BIG Question?

 

**SUMMARY movie of how sun angle and length of day changes throughout the year**

WHAT’S YOUR NOON SUN ANGLE?

 

Simple formula:

 

90 - latitude where you are +/- latitude where sun is 90 degrees at noon (“subsolar point”)

o   If sun’s subsolar point and your location are in different hemispheres, ADD

o   If sun’s subsolar point and your location are in same hemispheres, SUBTRACT

How do I know the subsolar point?

o   Analemma (Castaway!) and Memorize location on:

o   December 22 solstice: Tropic of Capricorn (23.5 degrees S)

o   March 22 equinox: Equator (0 degrees)

o   June 22 solstice: Tropic of Cancer (23.5 degrees N)

o   Sept 22 equinox: Equator (0 degrees)

o   Extreme example:

o   22 December (winter solstice)...where’s the subsolar point?

o   You just won a trip to Oulu, Finland (latitude = 64 degree N)

o   What’s the angle of the sun at noon?

o   Subsolar point & your location are in different hemispheres, so ADD: 64 + 23.5 = 87.5

o   Noon Sun Angle = 90. Thus, 90 - 87.5 = 2.5 degrees (the sun would be 2.5 degrees above the horizon at noon)

o   Equation looks like this: 90 - (64 + 23.5)

o   Denver Example:

o   Latitude ~39 degrees. Noon sun angle for today is?

o   So...90 - (39 +/- x) = noon sun angle for Denver today (could check with a sextant)

 

Why should I care?

o   To know where not to live

o   To understand Groundhog Day

o   Because high angles make some places warm for migration

 

Extras:

o   At Stonehenge: on what side are the shadows?

In New Zealand: are the melting snow patches facing north or south? What exposure protects the snow from the sun?

 

C. Other Ways to Visualize:

o   If you were the sun, looking straight down (90 degrees) at the subsolar point (latitude at which sun is directly overhead at noon), this would be how the year would seem (movie)

o   NOTE: from our vantage point, the sun is overhead twice each year BETWEEN the tropics of Capricorn and Cancer

o   COOL VIEW: If you looked at earth for one year, this movie is the way the tilt would affect the division between night and day

·        So...who has the surplus/deficit?

·        Why don’t the poles freeze and the equator cook?