Earth and science

• Earth and life science


  The study of the earth and living and non-living organisms
• Earth and life science is an interesting topic, not least because it affects us all
• The study of the earth and the living things within it is important if you want to understand how the environment works, as well as plants and animals
• Earth and the solar system


  Needs to be defined in order to understand the basis of the topic
• Creation of the earth

  1. Cloud of dust and gases formed the inside of the earth

  2. Elements in the solid center of the earth started to decay

  3. Radioactive materials emitted heat

  4. Iron sank towards the center forming the core

  5. Rock layer formed around the core

  6. Depressions on the surface where water accumulated
• Earth's structure


  • Two magnetic fields that repel solar wind and protect from radiation
  • Stratified atmosphere made up of mainly nitrogen and oxygen
  • Variety of minerals, melts, fluids, gases, and volatiles
  • Layers: crust, mantle, metallic core
  • Outer lithosphere and plastic asthenosphere
• Earth's subsystems


  • Geosphere
  • Hydrosphere
  • Atmosphere
  • Biosphere
• Atmosphere


  Layer of air that surrounds the earth, protects from solar rays, circulates air and gases
• Biosphere


  Living organisms, plants and animals, interacts with other spheres
• Geosphere/Lithosphere


  Physical earth, rocks, magma, soil, extends from center to atmosphere
• Hydrosphere


  All the water held on earth, water molecules in air, icebergs, lakes, rivers, oceans
• Atmospheric layers


  • Exosphere
  • Thermosphere
  • Mesosphere
  • Stratosphere
  • Tropopause
  • Troposphere
• Earth's crust


  • Thickest under mountain ranges, thinnest under mid-ocean ridges
  • Mohorovicic discontinuity separates crust from upper mantle
  • Two types: continental and oceanic
  • Composed of 8 elements, oxygen most abundant
• Earth's mantle


  • Solid rock layer between core and crust
  • Composed of peridotite
  • Cool mantle sinks, hot mantle rises
  • Upper, transitional, and lower subdivisions
• Earth's core

  • Iron-rich sphere with radius of 3471km
  • Outer core is liquid iron, nickel, and sulfur, 2255km thick
  • Outer core flow creates magnetic field
  • Inner core is solid nickel-iron alloy, radius of 1220km
• The universe and the solar system were formed about 4.6 billion years ago
• Formation of the sun

  1. Spinning disk in space

  2. Gas collected in center formed protosun

  3. Molecules collided causing heat to form

  4. Heat and collisions allowed nuclear reactions to turn protosun into a star
• Formation of the planets

  1. Accretion process in disk around protosun

  2. Small particles crashed together to form planetesimals

  3. Planetesimals' gravity caused more collisions

  4. Near sun, water evaporated and gases swept away, heavier materials formed planets

  5. Farther from sun, cooler temperatures allowed ice to form larger bodies like Jupiter and Saturn
• Big Bang Theory


  All matter and energy was once in a small, dense ball that exploded and expanded, forming the universe
• Steady State Theory


  Universe is uniformly the same in space and unchanging in time, with new matter continuously being created to fill expanding space
• Plasma Universe Theory


  Universe is composed of 99% plasma, a hot ionized gas, rather than the Big Bang or Steady State models
• Glossary


  • Accretion
  • Nuclear reaction
  • Planetesimal
  • Plate tectonics
  • Protosun
  • Radioactive
  • Silicates