Creation of the Earth

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Creation of the Earth

• The earth is 4.6 billion years old.
• After the big bang, the young planet earth
  formed from accretion. Accretion is the process
  of growth from accumulation. The earth, due to
  its initial large size used its gravitational
  pull, toattract smaller moons, planetesimals,
  asteroids and meteoroids and grew in mass.
• The materials that fell to earth were made up of
  silicon, iron, magnesium, water and other
  volatile elements that turn into gases at low
  temperatures.
• As the exterior of the earth cooled and hardened
  once the solar winds blew away most of the
  asteroids and meteoroids, the interior remained
  molten.

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• The heavy material sank down into the core of
  the earth - Nickel and Iron, while the lighter
  materials stayed on top on the earths crust -
  Silicon, magnesium and aluminum.
• As the rocks melted and later cooled they gave
  off gasses which created an atmosphere. Volcanic
  eruptions also added gases to the new atmosphere.
  
• The crust after cooling had temperatures that
  ranged from boiling to freezing. Water vapour
  began to be converted into liquid and solid. The
  liquid fell as rain and filled up the lower lying
  areas creating the first oceans.
• The earliest signs of life on earth are in rocks
  3.5 to 3.8 billion years old. Early life depended
  on small amounts of oxygen. The oceans were the
  most favourable.
• Early life forms used the process of
  photosynthesis to create food from sunlight,
  carbon dioxide and other minerals and a by
  product of this process was oxygen.

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1. Meteorite bombardment of the early earth added
to its size and the heat of the impacts kept the
earths surface in a molten condition. This
process slowed when the suns nuclear furnace
ignited and the suns newly created solar wind
blew away all but the largest of asteroids and
meteoroids.
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2. Heating and meteorite impacts, gravitational
compression and , most importantly, radioactive
decay melted the interior of the earth. This
melting enabled Iron and Nickel to sink down to
the center to form the core of the earth. The
lighter elements like Silicon and Magnesium and
Aluminum rose to the mantle and crust. This is
known as differentiation.
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3. The melting of the interior also freed many
volatile gases such as carbon and sulphur
dioxide, hydrogen, ammonia, methane, and water
vapour from their rocky traps. These gases worked
their way to the surface to form an atmosphere.
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4. The arrival of life forms began the
transformation of the poisonous atmosphere of
carbon dioxide, ammonia, methane and sulphur
dioxide and water vapour into an oxygen rich one
through the process of photosynthesis (remember -
sunlight and carbon dioxide are used to produce
food and oxygen is a by product).
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Below is a short movie on the origins of the
solar system!