Evolution of Earth

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Evolution of Earth

• Earths Formation and Composition
• College Environmental Science/Mrs. Cirillo

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So How did it All Begin?

• Most generally accepted theory is the Big Bang
• All matter and energy was compacted into a single
  inconceivably dense point which then exploded
  outward creating our universe
• This occurred around 13.5 billion years ago

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The Nebular Hypothesis

• Immanual Kant proposed that the planets and our
  sun formed from a giant rotating cloud of gas and
  dust known as nebulae
• Force of gravity contracted the cloud and in turn
  accelerated the rotation of the particles
• This fast spinning flattened the disc

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The Sun Forms

• The early sun was known as the proto-sun
• It compressed under its own weight, and became
  dense and hot until the process of nuclear fusion
  began, allowing the sun to release some of the
  energy it produced as sunshine

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The Planets Form

• Planets formed as the solar nebula cooled and
  condensed into sticky kilometer sized chunks
  called planetesimals
• The innerplanets formed as the denser less
  volatile material accreted together, leaving the
  gases and more voltile material to form the outer
  planets further away from the sun

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Earth Forms

• Early Earth was a molten mass
• As it cooled, a process known as differentiation
  transformed the mass into layers according to
  their density
• The most dense material formed the inside of
  earth or the core, and the less dense material
  formed the crust
• Earth is thought to be 4.53 billion years old
• Radioactivity and meteor impacts kept the earth
  hot

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Earths Spheres Form

• The solid earth (continents and ocean floor)
  formed soon after earth differentiated, and goes
  through a constant cycle of growth and
  destruction throughout time
• The liquid and earth formed from escaping
  volcanic gases and comet ice
• The gaseous earth formed from escaping volcanic
  gases as well

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Our Dynamic Earth

• Earths crust evolves and changed throught time
  by moving, eroding, melting, recrystallizing,
  crystallizing,and deforming
• These processes have lead to the formation of our
  natural resources and cycling of materials

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So it is what it is

• This means all the resources we have on the
  planet were created by this

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