earth

• Earth is approximately 4.54 billion years old +/- 50 million years

  
• Astronomical unit (AU)


  The average distance between the Earth and the Sun, which is about 150 million km

  
• Layers of the Earth

  • Core (inner and outer)
  • Mantle
  • Crust

  
• Inner Core


  • - Solid, hot, dense ball of (mostly) iron
  • Radius: 1220 km
  • Temperature: 5200°C
  • Pressure: 3.6 million atmospheres (atm)
• Outer Core


  • - Mostly composed of liquid iron and nickel
  • Thickness: about 2200 km - 2250 km
  • Temperature: 4500°C to 5500°C
• Mantle


  • - Makes up most of the Earth's interior
  • Layer of molten rock between the solid crust and the hot, dense core
  • Thickness: about 2900 km
  • Temperature: 1000°C to 3700°C

  
• Crust


  • - Outermost layer
  • Makes up 1% of the Earth's mass
  • Made up of solid rocks and minerals
  • Continental crust - older, thicker
  • Oceanic crust - younger, denser

  
• Continental crust and oceanic crust


  Different types of crust

  
• What makes the Earth habitable


  • - Right distance from the sun
  • Protected from harmful solar radiation by its magnetic field
  • Kept warm by insulating atmosphere
  • Has the right chemical ingredients for life, including water and carbon
  • Elements are continuously cycled in the environment
• It is important to study and explore the Earth
• Crust is the outermost layer of the Earth

  
• It takes the Earth 365 days to revolve around the sun
• The inner core is made up of solid iron and nickel, not molten rocks
• The continental crust is thicker than the oceanic crust

  
• Carl Sagan: 'Preserve and cherish the pale blue dot, the only home we've ever known.'