dynamic earth

• Categories of planets in the solar system

  • Terrestrial planets (inner planets)
  • Jovian planets (gas giants or outer planets)
• The force that makes planets continue spinning is inertia, working together with the sun's gravitational field to create stable orbits
• Chapter 1 topics

  • The Dynamic Earth
  • The Solar System
  • The Planet Earth
  • Continental Drift and Plate Tectonics
  • The Geologic/Rock Cycle
  • Unravelling the History of the Earth
  • Geomorphology
  • Summary
  • Review Questions and Critical Thinking
• The Big Bang Theory manifested a cataclysmic origin of the universe around 15 to 20 billion years ago
• The remaining gases and dust condensed and rotated around the young sun, forming the planets over 4.5 billion years ago
• In 2006, Pluto was declared a Trans-Neptunian Object (TNO) due to not satisfying the criteria for a planet
• Most astronomers have accepted the Big Bang Theory on the origin of the universe
• The composition of planets depends largely on their distance from the sun, with the farther planets being different in composition
• The sun and the circling planets are believed to have formed from a rotating cloud of dust and gas about 5 billion years ago
• The Universal Law of Gravitation of Sir Isaac Newton explains the circular orbits of celestial objects
• The origin of the universe has been a controversy since ancient civilizations existed
• Stars are not permanent objects and are constantly losing energy as they burn their own fuel
• Properties for a celestial object to be classified as a planet by the IAU


  • Orbits the sun
  • Enough mass to form a sphere
  • Dominant gravitational influence along its orbit
• Protoplanets grew and became planets due to the sun's gravitational field, forming elliptical orbits that became more circular over time
• The Terrestrial planets are dense and rocky, while the Jovian planets are mostly gaseous
• Jovian planets


  • Jupiter
  • Saturn
  • Uranus
  • Neptune
• The composition of the planets depends largely on their distance from the sun

  The farther you move from the sun, the lower the temperature conditions will be
• Mercury, Venus, Earth, and Mars are predominantly rocky and metallic planets
• Earth's mantle


  Mainly iron, magnesium, silicon, and oxygen combined in various proportions in several different minerals
• Heating of the Earth

  1. Impact of colliding dust particles

  2. Compression of the interior developed by gravity triggering nuclear reactions

  3. Decay of radioactive elements releasing heat
• Origin of the oceans on Earth could have been from water found in minerals that compose the upper layers of the Earth
• The Earth is about 150 million kilometers away from the sun and has an oblate spheroid shape with a flattened poles and bulging equator due to rotation
• Jovian planets

  Bigger in sizes but are mostly gaseous
• Planets relatively far from the sun are composed of low temperature minerals with water interlocked into their crystal structure
• Earth's core

  Mostly iron, with some nickel, and few minor elements
• The planet Earth is theorized to be heated up by several processes including the impact of colliding dust particles and nuclear reactions
• Terrestrial planets

  • Mercury
  • Venus
  • Earth
  • Mars
• Formation of the lithosphere, hydrosphere, and atmosphere approximately 4 billion years ago
• Jupiter, Saturn, Uranus, and Neptune are predominantly gaseous planets
• Earth's crust


  Chemically diverse based on the average composition of the Earth
• Planets nearest to the sun are composed of high temperature minerals (such as metallic iron), a few minerals with very high melting temperatures, and with little water or gas
• Formation of the Earth's compositional zones

  Heating led to the melting of materials resulting in the development of core, mantle, and crust
• Terrestrial planets


  Dense and mostly rocky in composition
• Formation of oxygen in the atmosphere connected to the existence of cyanobacteria capable of photosynthesis
• With flattened poles


  The distance of the poles to the earth’s core, which is of high density (Fe-Ni), is relatively shorter than that of the equator
• A mathematician named Eratosthenes approximated the circumference of the earth to be about 45,000 km


  3rd century B.C.
• Continental rocks are much older, approximately 3.8 billion years old, compared to oceanic rocks which are estimated to be about 150 million years old
• Gold mines and depositories affect land surveys due to the high density of gold, giving erratic data
• Continents are mostly found in the northern hemisphere, while ocean basins occupy about 69% of the earth’s surface
• Gravity pull is influenced by the earth's core density and its distance from the point of measurement


  Exemplified with the use of a surveying instrument aided by a plumb bob