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THE PRIMORDIAL EARTH
Hadean and Archean Eons
Solar System
Includes:
Sun
Planets
Moons
Asteroids
Comets
THE PRIMORDIAL EARTH
Hadean and Archean Eons
Terrestrial or Inner Planets
Mercury
THE PRIMORDIAL EARTH
Hadean and Archean Eons
Terrestrial or Inner Planets
Venus
THE PRIMORDIAL EARTH
Hadean and Archean Eons
Terrestrial or Inner
Planets
Earth
Small
Dense (4 - 5.5 g/cm3)
Rocky and
include Metals
THE PRIMORDIAL EARTH
Hadean and Archean Eons
Diameter ± 13,000 km (8000 mi)
Oceans cover > 71% of surface
Atmosphere:
78% nitrogen
21% oxygen
Average density = 5.5 g/cm3
Crust density = 2.5 - 3.0 g/cm3
Core is densest
Mantle surrounds core.
Surface temperature ranges
between roughly -50 and +60 °C.
THE PRIMORDIAL EARTH
Hadean and Archean Eons
Terrestrial or Inner Planets
Mars
THE PRIMORDIAL EARTH
Hadean and Archean Eons
Asteroid Belt
Between Mars and Jupiter
Likely a broken up planet or
planetesimal
THE PRIMORDIAL EARTH
Hadean and Archean Eons
Jovian or Outer Planets
Jupiter
Large
Low density (0.7 - 1.5 g/cm3)
Gaseous
THE PRIMORDIAL EARTH
Hadean and Archean Eons
Outer Planets
Saturn
THE PRIMORDIAL EARTH
Hadean and Archean Eons
Outer Planets
Uranus
THE PRIMORDIAL EARTH
Hadean and Archean Eons
Outer Planets
Neptune
THE PRIMORDIAL EARTH
Hadean and Archean Eons
Outer Planets
Pluto
THE PRIMORDIAL EARTH
Hadean and Archean Eons
THE PRIMORDIAL EARTH
Hadean and Archean Eons
Sun
The Sun is a star
Composition
70% hydrogen
27% helium
3% heavier elements
Temperature
>20,000,000 ºC at interior
Energy comes from fusion of Hydrogen to form Helium
THE PRIMORDIAL EARTH
Hadean and Archean Eons
Sun
Sun's energy is the force behind many geologic processes on Earth:
Evaporation of water to produce clouds which
causes precipitation which causes erosion
Uneven heating of the Earth's atmosphere causes
winds and ocean currents
Variations in heat from sun may trigger continental glaciations
Sun and moon influence tides
THE PRIMORDIAL EARTH
Hadean and Archean Eons
Moon
The Moon is a satellite
Diameter ± 1700 km
Density ± 3.3 g/cm3
Rotates on its axis at same rate as
it revolves around Earth,
which results in same side
of Moon always facing Earth.
Far side of moon is more densely cratered
Dominant rock type is anorthosite
(related to gabbro)
THE PRIMORDIAL EARTH
Hadean and Archean Eons
Geology of the Moon
Lunar highlands
Light-colored
Rough topography
Highly cratered
More than 4.2 billion
years old (Hadean in age)
Maria (once thought to be seas)
Singular = Mare, plural= Maria
Large, dark areas
Covered with basaltic lava flows
Age of basalt is 3.8 to 3.2 billion years
THE PRIMORDIAL EARTH
Hadean and Archean Eons
Origin of the Moon
Moon may have formed
as a result of an impact of
another body with Earth
about 4.4 billion years ago.
Debris from the impact
thrown into orbit around
Earth and aggregated to
form the Moon.
THE PRIMORDIAL EARTH
Hadean and Archean Eon
Origin of the Moon
Heat from impacts led to melting and differentiation
(or segregation of materials of different density;
low density materials rose and high density materials
sank).
1. Low density alumino-silicates rose to surface to
form a crust
2. Higher density iron-rich minerals sank to form
the lunar mantle, and possibly a small core
3. Basaltic lava flows of the maria erupted following
large impacts somewhat later.
THE PRIMORDIAL EARTH
Hadean and Archean Eon
Origin of the Moon
THE PRIMORDIAL EARTH
Hadean and Archean Eons
Origin of the Universe
Big Bang Theory
Evidence:
1. The galaxies are rapidly moving apart (Hubble's Law);
indicates that galaxies were closer together in the past
(This was discovered in 1929 by Edwin P. Hubble;
In 1914, W.M. Slipher first noted the red shift.)
THE PRIMORDIAL EARTH
Hadean and Archean Eons
Origin of the Universe
THE PRIMORDIAL EARTH
Hadean and Archean Eons
Origin of the Universe
Red shift:
Light is shifted toward the red (or long wavelength)
end of the spectrum.
Colors of the spectrum
ROY G BIV
1.
2.
3.
4.
5.
6.
Red
Orange
Yellow
Green
Blue
Indigo
7. Violet
THE PRIMORDIAL EARTH
Hadean and Archean Eons
Origin of the Universe
THE PRIMORDIAL EARTH
Hadean and Archean Eons
Origin of the Universe
Red = long wavelengths
Blue = short wavelengths
Microwaves and radio waves are longer than visible
Ultraviolet and X-rays are shorter than visible.
THE PRIMORDIAL EARTH
Hadean and Archean Eons
Origin of the Universe
The spectrum of a star reveals:
•The star's composition (by means of absorption
lines; various elements in the star's atmosphere
absorb parts of the light of the spectrum) and
•Whether it is moving toward or away from the
Earth (and at what speed).
THE PRIMORDIAL EARTH
Hadean and Archean Eons
Origin of the Universe
Light reaching us from distant receding galaxies has its
absorption lines shifted toward the red end of the
spectrum.
This indicates that the galaxy is moving away from the
Earth.
So, the red shift indicates that the universe is
expanding.
A similar phenomen, except related to sound, is the
Doppler Effect.
At rest
Away from you
Towards you
THE PRIMORDIAL EARTH
Hadean and Archean Eons
Origin of the Universe
Big Bang Theory
Evidence:
2. Observed temperature of the universe today
(background microwave radiation) 3 degrees
above absolute zero
THE PRIMORDIAL EARTH
Hadean and Archean Eons
Origin of the Universe
Big Bang Theory
Evidence:
3. Present abundances
of hydrogen and helium.
THE PRIMORDIAL EARTH
Hadean and Archean Eons
Formation of the Solar System
The Solar Nebula Hypothesis