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Evolution of Earth

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Title: Evolution of Earth


1
Evolution of Earth
  • Earths Formation and Composition
  • College Environmental Science/Mrs. Cirillo

2
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

3
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

4
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

5
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

6
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

7
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

8
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

9
So it is what it is
  • This means all the resources we have on the
    planet were created by this

10
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