Transcript Density and Planetary Differentiation

Density and Planetary
Differentiation
• Planetary Differentiation is the separating of
a planet into different layers due to
differences in density.
• Seismic waves tell scientists Earth has four
layers of different densities because of their
speed.
Density of Earth in g/cm^3
Early Earth
• Scientists infer Earth was formed 4.6 billion
years ago.
• When Earth first formed, it was extremely hot!
• The entire planet was a ball of molten
elements held together by gravity.
Elements Settled
• While Earth was hot, elements began to settle
by density.
• Denser elements sank and less dense
elements floated.
• Iron, Nickel, and several other heavy elements
(metals) sank to form the inner and outer
cores.
• Elements such as Magnesium and Iron
silicates (denser rocks) settled in the middle
forming the mantle.
• Lighter elements such as Sodium and
Potassium Silicates (less dense rocks) settled
on the surface forming the crust.
• Liquids (water) formed the oceans above the
crust and gasses formed the atmosphere.
Layers vs No Layers
• Scientists can infer that a planet with out
layers must have been cooler than Earth when
formed.
Which moon(s) of Jupiter formed
molten?