Basics of Geography and the Universe

Geography as a Discipline:

• Geography explores the relationship between the planet, humans, and the environment.
• Geographic study focuses on relationships between different places.
• Greeks initiated studies on Earth and the cosmos, and are considered the world's first geographers.
• Eratosthenes coined the term "geography" and is known as the Father of Geography.
• "Geography" is derived from "geo" (Earth) and "graphe"/"graphos" (description).
• The literal meaning of geography is description of the Earth.
• Geography is associated with disciplines like soil geography (pedology), ecology, and environmental science.
• Climate study includes rainfall, temperature, and location analysis.
• Geography is related to meteorology (study of the atmosphere), climatic systems, and hazard warnings.
• Geography integrates various fields.

The Universe:

• The universe contains all matter and energy in a vast space.
• The exact size of the universe is unknown.
• The universe is continuously expanding.
• Geoscentric and heliocentric views differ on the universe's center.
• The geoscentric view posits Earth at the center.
• The heliocentric view places the Sun at the center, with planets revolving around it.
• The heliocentric view is more widely accepted.
• Aristarchus first proposed the heliocentric view.

Big Bang Theory:

• The Big Bang Theory is the most accepted theory about the universe's origin.
• Initially, the universe was a singularity.
• The singularity exploded, causing the universe to expand.
• Early expansion was rapid, then slowed.
• Expansion continues today.
• The Big Bang Theory explains the expanding universe.
• Edwin Hubble provided evidence for the expansion of the Universe.
• Lemaitre first presented the Big Bang, but Hubble is considered its proponent due to his evidence.
• The early universe was a tiny ball.
• An explosion occurred 13.7 billion years ago, leading to a massive expansion.
• Hoyle's Steady State theory suggests the universe maintains a constant size.

Galaxies:

• A galaxy is a massive collection of gas, dust, billions of stars, and a solar system.
• Three main galaxy types exist: spiral, elliptical, and irregular.
• Spiral galaxies actively form stars.
• Elliptical galaxies consist mainly of old stars.
• Irregular galaxies lack stars and mainly consist of dust.
• The Milky Way galaxy is a spiral galaxy.

Milky Way Galaxy:

• The solar system is located in the Milky Way galaxy.
• It spans 100,000 light years.
• The Milky Way's age is 13.6 billion years.
• The Milky Way is a spiral galaxy with three main parts: galactic center, bulge, and disk.
• A Black Hole called Sagittarius A is at the galactic center.
• The sun is in the galactic disk.
• Andromeda is the Milky Way's closest neighboring galaxy.

Stars:

• Stars are luminous celestial bodies made of matter and energy.
• They shine brightly at night.
• Stars are very hot and emit light.
• Hydrogen and helium primarily compose stars.
• The sun is a star.

The Sun:

• The sun is the solar system's central celestial body.
• It emits its own light and consists of hydrogen and helium.
• The sun is estimated to be 5 billion years old.
• The sun's mass accounts for 99.8% of the solar system's total mass.
• It is about 150 million kilometers from Earth.

Sun's Temperature Gradient:

• The core is the hottest part, about 15 million degrees Celsius.
• The surface is approximately 5,500 degrees Celsius.

Sun's Composition:

• The sun is 98% hydrogen and helium.
• Its mass equals 329,000 Earths.
• The Sun is 109 times bigger than Earth.

Sun Layers:

• Inner Layers: Core, Radiative Zone, and Convective Zone.
• Outer Layers: Photosphere, Chromosphere, and Corona.

Functions of the Sun's Layers:

• Core: Nuclear fusion of hydrogen into helium occurs here.
• Radiative Zone: Between the core and convective zone.
• Convective Zone: Area where convection occurs.
• Photosphere: The surface of the sun.
• Chromosphere: A thin layer above the photosphere.
• Corona: The outermost layer, visible during a solar eclipse.

Sun Spots:

• Sunspots are dark spots on the sun's photosphere.
• They are cooler regions, about 500-1500°C cooler.

Solar Wind:

• A stream of plasma flows outward from the Sun's corona, called Solar Wind.
• Plasma consists of ionized gases (hydrogen, helium) forming electrons and protons.

Aurora:

• Aurora's are natural light displays in the sky, predominantly at high latitudes (Arctic and Antarctic).

Planets:

• Planets revolve around the Sun or a star in an elliptical orbit.
• There are eight planets in our solar system.
• There are also five dwarf planets.

Expansion on Different Types of Planets:

• Inner Planets: Mercury, Venus, Earth, and Mars; rocky and earth-like.
• Outer Planets: Jupiter, Saturn, Uranus, and Neptune; gaseous and large, also called Jovian Planets.
• Venus revolves in the opposite direction of Earth.

Pluto:

• Pluto has been categorized as a dwarf planet since 2006 by the International Astronomical Union (IAU).

Theories related to Pluto:

• Pluto must orbit the Sun to be considered a full planet.
• Must have enough mass to assume hydrostatic equilibrium, creating a round shape.
• A planet must clear its orbital neighborhood, which Pluto does not.

Kuiper belt:

• A doughnut-shaped region beyond Neptune's orbit is the Kuiper belt.
• It contains icy bodies and four dwarf planets.
• The dwarf planets are Pluto, MakeMake, Haumea, and Eris.

Other Celestial Bodies: Asteroids and Comets

• Asteroids are small, rocky objects orbiting the Sun.
• Comets are large objects made of frozen gases and dust orbiting the Sun, and they develop tails when approaching the sun.
• Meteors enter the Earth's atmosphere.
• Meteoroids are space rocks, from dust grains to small asteroids.
• Meteorites are meteors that survive atmospheric entry and hit the ground.

Globes, Latitude, and Longitude:

• A globe is a model of the Earth.
• Latitude and longitude are imaginary lines pinpointing locations on Earth.
• Latitude measures a location's distance from the equator.
• Lines of latitude run horizontally, north and south of the equator.
• The equator is 0 degrees latitude.

Types of Geographic measurements:

• Latitude is measured from 0 to 90 degrees, north and south.
• Latitude lines are called "parallels" because they are parallel to each other.
• One degree of latitude covers about 111 kilometers.

Latitude References:

• The Equator is at 0°.
• The Tropic of Cancer is at 23.5°N.
• The Tropic of Capricorn is at 23.5°S.
• The Arctic Circle is at 66.5°N.
• The Antarctic Circle is at 66.5°S.

3 different Heat Zone classifications:

• The Torrid Zone is located between the Tropic of Cancer and the Tropic of Capricorn.
• The Temperate Zone is located North and South of the Tropics with variable conditions.
• The Frigid Zone is at the poles, with the coldest areas.

Longitude:

• Longitude measures east and west relative to the Prime Meridian, which passes through Greenwich Observatory in Britain.
• Longitude lines run vertically and connect at the north and south poles.

Longitude to Time Conversion:

• Earth rotates 360° in 24 hours.
• Earth rotates 15° per hour, or 1° every 4 minutes.

Expansion on Time Zones

• Daylight Saving Time involves advancing clocks in summer months.
• The goal is to better utilize daylight for energy savings.
• Daylight Saving Time is observed in the USA, Canada, the European Union, Argentina, and Cuba.

Motions of the Earth:

• Two movements influence Earth, rotation and revolution.

Rotation:

• Earth spins on its axis.
• Rotation creates day and night.
• Rotation takes approximately 24 hours (23 hours, 56 minutes, 4 seconds).
• This period defines an "earth day".

Revolution:

• Earth orbits the Sun in an elliptical path.
• One revolution takes about 365 days and 6 hours.
• The additional 6 hours create Leap Years.

Definition of a Leap Year:

• A leap year involves adding an extra day to February every fourth year.
• This keeps the calendar aligned with the Earth's orbit.

Two Important positions:

• Aphelion: Earth is farthest from the Sun, around July 4th.
• Perihelion: Earth is nearest to the Sun, around January 3rd.

Earth and The Seasons:

• Seasons are caused by the Earth's revolution and axial tilt.
• Earth's axis is tilted at 23.5 degrees.

Different solstices:

• Summer Solstice: The Northern Hemisphere is tilted toward the Sun, and the north pole has 24 hours of daylight (June 21st).
• Winter Solstice: The Northern Hemisphere is tilted away from the Sun, and there are 24 hours of darkness(December 21st).

About Equinoxes:

• Equinoxes occur when direct rays of the sun fall on the equator.
• Days and nights are equal.
• The Spring Equinox takes place around March 21st.
• The Autumn Equinox takes place around September 23rd.

Study Notes - Geography (28 Hr Series): Geomorphology - Day 2

Introduction to Geomorphology:

• Geomorphology studies Earth's landforms and the processes shaping them.
• The word is comprised of ‘Geo’ (earth) and ‘Morph’ (structure).
• It examines physical and chemical changes influencing Earth’s surface.

Sources of Information for Studying Earth

• Information is gathered through direct and indirect methods.
• Direct methods include volcanic eruptions, mining and drilling, and surface rock studies.
• Indirect methods include analyzing Earth's gravitational field, magnetic field, and seismic knowledge.

Structure of the Earth:

• The Earth has three main layers: the Core, Mantle, and Crust.
• The outermost layer is the Earth's crust.

Expansion on the different layers of earth to structure:

• Crust: Divided into Continental and Oceanic parts.
• Continental crust is thicker (40 km) but lighter.
• Oceanic crust is thinner (5 km) but denser.
• Continental crust is composed of granite rocks and comprises "sial" (silica and aluminum).
• Oceanic crust is composed of basalt rocks and comprises "sima" (silica and magnesium).
• Mantle: Located between the crust and the core and made of the Upper and Lower Mantle.
• The uppermost part of the Mantle plus the Crust makes up the Lithosphere.
• Lithosphere: It is broken into slabs known as lithospheric or tectonic plates.
• The Lithosphere is also known as “plates” from the theory “Plate tectonics”.
• Asthenosphere: It is partially melted and is a weak zone just beneath the lithosphere; its lower portions are known as the lower mantle.
• Core: divided into inner and outer zones.

Earths Interior:

• Temperature increases towards Earth's interior.

Outer and Inner Core:

• Outer Core: Liquid, due to temperature, produces the magnetic field.
• Inner Core: Solid

Composition of each layer:

• Crust: Continental = Sial (silica and aluminum), 1% volume/mass of Earth; Oceanic = Sima (silica and magnesium).
• Mantle = pyrocene, 83% of volume, 67% mass.
• Core = nife (nickel and iron), 16% of total.
• Lithosphere is over the Asthenosphere.

Earth's Magnetic Shield:

• Originates from the liquid outer core.
• Eclipse can create Corona.

Geological Discontinuities:

• Boundaries between different layers exhibiting seismic activities.
• Types of discontinuities: Conrad, Mohorovicic (Moho), Repetti, Gutenberg, and Lehmann.

Discontinuties Explained:

• Conrad Discontinuity: occurs between the Continental and Oceanic crusts.
• Moho Discontinuity: exists between the Crust and Mantle.
• Repetti Discontinuity: occurs in the mantle.
• Gutenberg Discontinuity: found between the Mantle and Core.
• Lehmann Discontinuity: found between the Convection Zone (Mantle) and the Core.

Earth Main Component Explained:

• Earth is 30% Land (Continents) and 70% Water
• Three kinds of movement can occur: Tectonic Movements (T), Weathering Process (W), and Erosion Process (E).
• Energy is used to change earth; all processes are linked.

Earth’s Magnetism:

• Earth has magnetic and geographical poles.
• Poles are at a slight angle.
• The difference between Geographical and magnetic creates Declination.
• Polar reversals: Poles can shift at times.

Geomagnetic Definitions:

• Earth is known as the Magnetosheath, and it acts as a boundary between space and earth.
• Magnetopause: Boundary between Magnetosheath/Solarwinds.
• Magnetosphere: Space surrounding Earth's poles.

Geomorphic Processes

Exogenic vs Endogenic Defined:

• Endogenic forces are internal forces from Earth's interior.
• Exogenic forces are external forces derived from the sun.
• Endogenic forces are constructive, while exogenic are destructive.

Subdivisions of Endogenic vs Exogenic:

• Endogenic is divided into Sudden (Earth Quakes (EQ) and Volcanism) and slow Diastrophic movements.
• Diastrophic is broken into: Orogenic (Mountain Building) and Epirogenic (Land building on continents) which can move vertically with uplift/subsidence.
• Exogenic forces have the same forces which is denudation or erosion, happening through Weathering, Mass process, and Erosion.
• Compression: Compacting objects.
• Tension: Pulling action.
• Shearing: Sliding and offset.

The process of Earth’s structure folding and faulting:

• Folding: Results from compression forces, bends that shorten the earth's crust.
• Faulting: Results from tension forces, causing crust movement.
• Important to know anticline versus syncline.
• Limb: slope
• Axial Plane: Line of folding.

Types of Folds:

• Symmetrical, Asymmetrical, Inclined, Overturned, and Recumbent

Faulting:

• Can give you Horst (up) and Gabel (Down movement).

Three Fault types:

• Normal, Reverse, and Transverse.

Expansions on Faults:

• Normal Fault: Pull action.
• Reverse Fault: Compression pushes block up.
• Transverse Fault: Sideways movement.

Expanison on Exogenic Process:

• What breaks them is the weathering or Erosion process.
• Weathering = disintegration (rocks break down in situ).
• Erosion= Weathering + Movement
• Also includes; Mass movement and transport.

Different Weathering Process:

• Physical/mechanical, Chemical, and Biological.

Biological Breakdowns:

• Roots and Homing Animals

Chemcial Reactions Include:

• Oxidation (Rust), Carbonation, and Hydration.

Phyiscal/ Mechanical is:

• Temperature (hot and cold) and Water Pressure.

Mass Movement include:

• Small amount of material moving to the side or downhill happens because of creep, soil flacion, and land Slides.

Theories of Formation of Earth:

Alfred Wegener Theory:

• Earth was together at “Pengala” then rifted apart and moved over time.

How does this happen? His evidence?

• Jig Saw fit of the continents
• Biological (fossils) found all over the planet as there used to be one super continent (Pengala), coal seams, planters (plant-based)
• Earths Structure (Mountain matching).
• Wegener incorrectly attributed forces to Tidal force (water) and Gravity.
• He died without understanding the source of these forces.

Harry Hess Theory:

• Describes plate movement with sea floor spreading.
• Daughter cells go from one point in the middle and push out towards ends. At ridges and trenches.

Plate Tectonics:

• Earth's lithosphere is divided into a number of plates that float on the asthenosphere.
• Earths Core floats on Lithosphere. Heat from deep inside the Earth moves towards the surface it moves in the asthenosphere, causing convection currents to cause the above move.
• Earth plates can move and can move 3 ways: Converge (crash), Diverge (Separated), and Transform (sliding).
• The Earth's Crust is the Lighosphere.
• Main plate names: Enclantic, North American, South American, Eusrailia, and Erusaian plates.