The Universe and The Earth

• Formation of the Universe and The Earth


  • the singularity - an inferior small region of space with zero volume and no dimensions
  • stuffing the entire universe into a singularity
  • state of universe before big bang
• Formation of the Earth - offshoot of the formation of the universe
• Formation of the universe: Big Bang Theory
• Formation of the Solar System: Nebular Hypothesis
• Big Bang Theory


  • contends that the universe originated from a cosmic explosion (origin unknown) that hurled matter in all directions 15 and 20 billion years ago
  • first proposed by the Belgian priest Georges Lemaitre, 1920
  • Edwin Hubble justified Lemaitre's theory through observations that the Universe is continuously expanding; galaxies are moving away from death other
  • diameter of the universe is estimated to be 93.016 billion light years
  • this diameter is increase at a rate of about 1.96 million km/s, which is about 6.5 times faster than the spread of light
• Evidence of the BBT

  • Cosmic Microwave Background Radiation (CMB)
  • uniform distribution of radiation that pervades the entire universe
  • abundance of primordial elements (H and He)
  • Hubble's Law
  • Edwin Hubble observed a "redshift" in 1929
• Redshift

  • galaxies have been stretched as time passes
  • violet: red; shortest wavelength; longest wavelength
  • humahaba yung wavelength of the stars
  • lumalayo yung stars
  • evidence that we were once "near"
  • if the universe is expanding, it must be smaller in the past
• The Nebular Hypothesis 


  • the SS originated from a single rotating cloud of gas and dust, starting 4.6B years ago, which contracted due to gravity and came from products of the BB
  • the idea was first proposed by Immanuel Kant and Pierre Simon de Laplace in the 18th Century
  • formation of galaxies
  • H and He clunked up together to gas -> galaxies -> stars -> SS
  • Chronology: production of cloud of gas and dust; sun created due to contraction of gravity; excess particles becomes planets
  • chrondites (stony primitive meteorites have not been modified) - similar composition as Earth
• SS by mass

  Sun - 99.85%

  Jupiter - 0.10%

  Others - 0.04%
• Nebular Hypothesis (cont)

  • matter condense to form planets: terrestrial and jovian (gas giants)
  • nucleosynthesis: formation of new elements due to fusion in the sum and other stars
  • the sun is a 2nd and 3rd generation star
• frost line 


  divides terrestrial and jovian
• nebular hypothesis


  idea that a spinning cloud of dust mostly light elements (called nebula) flattened into a protoplanetary disk, and became a SS consisting of a star with orbiting planets
• supernova


  powerful and luminous explosion of a star
• the iron catastrophe

  • planet earth has no official name
  • the proto-earth has a dust ball
  • accretion > heating > differentiation
  • liquid iron sank to the core
  • lighter elements (O, Si, etc.) were displaced
  • heavy elements -> core
  • lighter elements -> crust
  • mantle -> light + heavy elements
• Causes of melting

  • heat from collision
  • heat from solar radiation
  • radioactive heat
  • increase in temp from contraction of Earth due to gravity
• Formation of the moon

  • started with a collision within a mars-sized planetesimal
• Formation of the Moon


  Collision with a mars-sized planetesimal
• Origin of the Atmosphere: Atmosphere formed by heating and differentiation

  1. Primordial (ancient) mass lost to space due to solar winds (timeline: 1.4 Ga)
  2. volcanic venting and icy cement release carbon monoxide, carbon dioxide, ammonia, methane, and water vapor (4.0 Ga outgassing/ venting/ degassing)
  3. steady additions of gases from volcanoes builds up the volume of atmosphere 
  4. blue green algae convert carbon dioxide to oxygen (3.5 Ga onwards) 
• How did the earth become differentiated

  because of the iron catastrophe
• Layers of the Earth: composition

  1. Core
  2. Mantle
  3. Crust
• Core

  • Heavier elements
  • Iron and nickel alloys
  • iron rich sphere with small amounts of Ni and other elements
  • ~3.5 km in radius
  • 16% of earth's volume
  • around 31% of the earth's mass
• Mantle

  • Iron rich
  • But diluted with lighter elements like O2, Mg
  • 2.9km thick
  • 83% of earth’s volume - largest
  • 68% of Earth’s mass
• Crust

  Thickness

  • Outermost layer 
  • Composed of lighter elements
  • O, Si, Al, Fe, Ca, Na, K, Mg 
  • Thickness varies 
  • Continent - 15-60km 
  • Oceans: 3-15km 
  • Less than 1% of the earth’s mass and volume 
• Layers of the Earth: Mechanical Properties

  1. Inner core
  2. Outer core
  3. Lithosphere (uppermost mantle, continental crust, oceanic crust)
  4. Asthenosphere (uppermost mantle and upper mantle)
  5. Mesosphere (lower mantle)
• Layers of the Earth

  1. Case of variable mechanical properties
  2. increase in both T and P
  3. increase in T -> Melting
  4. Increase in P -> Solidification
  5. Response of each to dominant variable at a certain depth
• Evidences that Supports the layers of the earth

  • Seismic waves
  • Xenoliths
• Seismic Waves

  • P waves
  • passes through solid and liquid elements
  • S waves
  • passes only through solid; stops sa outer core
• Xenoliths

  • thermally rounded peridotite xenolith in basalt lava
  • aka alienated rocks
  • it is not a meteorite
  • comes from the mantle
• Earth's large scale features

  • Continents
  • Ocean basins
• Continents: Plains, Mountain belts

  - North American cordillera

  - Appalachians

  - Caledonians

  - Alps

  - Alpine

  - Each African right

  - Himalayas

  - Himalayans

  - Circumpacific belt

  - Urals

  - Andes belt
• Ocean basins: Abyssal plains, mid-oceanic ridges, trenches 


  • Mid-oceanic ridges
  • Ridges that extend from the North Pole to South Pole 
  • Almost 60k km long 
  • East pacific rise ridge
  • Mid-Atlantic ridge
  • Central Indian ride
  • Southwest Indian ridge
  • Trenches
  • Philippine trench
  • Manila trench
  • Mariana trench
  • Move
  • Tyuku trench
  • Sumatran trench
  • Java Trench
  • New Hebrides Trench
  • Seamounts/guyots and abyssal plains
  • Islands Continental margin
• Trenches

  moves via tectonic plate movement: one will subduct or sink the other tectonic plate

  abundance is seem in the pacific ring of fire
• Seamounts/ guyots and abyssal plains


  contains: continental shelf, continental slope, continental rise, abyssal plane (sea floor, where ships sink), ocean ridge
• Seamounts 


  are about to be islands

  e.g., Hawaiian
• Theories of Isotasy

  Pratt's theory

  Airy's theory

  Flexural theory
• Isotasy


  Rising or falling of the earth
• Pratt's theory


  • Equal depths of the route of the lithosphere  
  • Different densities per location
  • Low density - bundok; umaakyat
• Airy's theory

  • Equal density sa buona lithosphere 
  • There is no difference
  • The difference: was malalim yung roots, may limitations sa pagangat nila
  • Anti-root 
• Flexural theory


  • Combination of airy’s theory and something else 
  • Lithosphere will take the form of the bundok 
• Equatorial circumference of the Earth is 40,076km