The Universe and the Earth
Geology 11: The Universe and the Earth
Overview
Course: Geology 11, 2nd Semester, AY 2024-2025
Focus: The formation and features of the Universe and Earth
Page 1: Course Information
Title: The Universe and the Earth
Institution: National Institute of Geological Sciences
Page 2: Course Outline
Formation of the Universe and Earth
Big Bang Theory
Nebular Hypothesis
Formation of the Moon
Iron Catastrophe
Formation of the Atmosphere
Earth’s Features
Layers of the Earth
Size of the Earth
Large Scale Features
Isostasy
Page 3: The Big Bang Theory
Introduction
First proposed by Georges Lemaitre in the 1920s
Distance Measurement
1 light-year = 9.4607 × 10^15 m
Evidence: Cosmic Microwave Background (CMB) radiation.
Page 4: Evidence for the Big Bang Theory
Primordial Elements:
Abundance of Hydrogen (H) and Helium (He)
Hubble's Law:
Observed "redshift" by Edwin Hubble in 1929
Indicates the universe is expanding
Suggests a smaller universe in the past
Page 5: Nebular Hypothesis
Proposed by Immanuel Kant & Pierre Simon de Laplace in the 18th century.
Process:
Formation of groups of primordial elements
Formation of Solar System from rotating gas-dust clouds due to gravity
Sun forms at center with planets forming from remaining material.
Age: Approximately 4.6 billion years old.
Page 6: Nucleosynthesis
Process of forming new elements by fusion in stars.
Page 7: The Solar System
By Mass: Overview of the components by mass distribution.
By Size: Overall size of the solar system.
Inner or Terrestrial Planets:
Rocky composition (Si, Fe, O)
Giant or Jovian Planets:
Lacks solid surfaces; gaseous or liquid forms (H, He, Ar, C, O, N)
Page 8: The Iron Catastrophe
Proto-earth Characteristics:
Initially a very hot dust ball.
Process:
Accretion leads to heating and differentiation.
Results:
Liquid iron sank to core displacing lighter elements.
Page 9: Causes of Melting in Proto-earth
Heating from:
Collisions
Solar radiation
Radioactivity
Temperature increase from contraction
Formation of the Moon:
Resulted from collision with Mars-sized planetesimal.
Page 10: Formation of Atmosphere
Timeline:
Formation around 4.5 billion years ago.
Outgassing occurring 4.0 billion years ago.
Significant atmospheric changes from 3.5 billion years onwards.
Page 11: Earth's Layers (By Composition)
Core:
Mainly iron-nickel alloy
Roughly 3500 km radius; ~16% of Earth's volume
Mantle:
Iron-rich, with more O, Si, Mg
Roughly 2900 km thick; ~83% of Earth's volume
Page 12: Earth's Crust
Composition:
Solid outer shell varying in thickness:
Continental: 15-60 km
Oceanic: 3-15 km
Constitutes less than 1% of Earth's mass and volume.
Page 13: Composition Breakdown
Element Weight Percentages in Crust:
O: 46.6%
Si: 27.7%
Al: 8.1%
Fe: 5.0%
Ca: 3.6%
Na: 2.8%
K: 2.6%
Mg: 1.5%
Page 14: Evidence for Earth's Layers
Sources of Evidence:
Xenoliths
Abundance of Fe in the solar system.
Page 15: Earth's Size
Circumference Measurements:
Equatorial: 40,076 km
Polar: 40,008 km
Historical Estimation:
Eratosthenes' estimate: 41,000 km
Page 16: Large Scale Features of the Earth
Continents: Plains and mountain belts
Oceans: Abyssal plains, mid-oceanic ridges, trenches.
Page 17: Notable Peaks
Mt. Everest: Tallest (8,848 m)
Mauna Kea: Tallest from base (10,210 m)
Mt. Chimborazo: Furthest from Earth’s center (6,268 m)
Page 18: Deepest Point
Challenger Deep: 11,035 m
Philippine Deep: 10,054 m
Page 19: Continuation of Large Scale Features
Further exploration of geological features and measurements.
Page 20: Theories of Isostasy
Concept: Explanations for Earth's varied topography
Floating Crust: Gravitational balance.
Page 21: Theories of Isostasy (Continued)
Pratt's Theory: Equal depth of lithosphere and density differences.
Airy’s Theory: Higher elevations correspond to deeper roots.
Flexural Theory: Accounts for lithosphere elasticity.