Origins & The Formation Of
The Universe
- The Big Bang Theory
- Galaxies and Stars
- Galaxy - a huge rotating aggregation of stars, dust,
gas and other debris held together by gravity.
- We live in the Milky Way Galaxy
- Stars - massive spheres of incandescent gasses.
- Solar System - The sun together with the planets
and other bodies that revolve around it.
- Solar Nebulas - The diffuse cloud of dust and
gas from which the solar system originated
- Protosun - Tightly condensed knot of material
that has not yet attained fusion temperature
- Planets - A smaller, usually nonluminous
body orbiting a star.
- New planets form from accretion - An increase
in the mass of a body by accumulation or clumping
of smaller particles.
- The Earth and the Ocean
- Formation of the Earth
- The Earth formed by the accretion of cold particles.
- The surface was then heated due to meteor impacts
- This caused the Earth to partially melt &
density stratification.
- Gravity pulled most of the iron to the core
- Lighter minerals rose towards the surface
- First surface on the Earth formed ~4.6 billion
years ago.
- A collision with a rocky body about the size
of Mars smashed into the Earth
- Rocky mantle of the object formed a debris
ring around the Earth
- The metallic core merged with the Earth's
- Radiation from the Sun stripped the outermost
layer of gasses (1st atmosphere) from the Earth
- Gasses trapped within the Earth were released
and formed a 2nd atmosphere
- The volcanic venting of volatile substances (outgassing)
condensed into clouds in the cool upper atmosphere
- Formation of the Oceans
- After millions of years, the clouds cooled enough
to form water droplets.
- At first, these hot rains were evaporated back
into the atmosphere
- As the Earth cooled, the water collected in
basins and dissolve minerals in the rocks.
- These rains may have lasted as long as 25 million
years.
- Water may have covered the Earth's surface
for 200 million years
- Composition of the Atmosphere
- The original atmosphere was much different
than today's
- Geochemists believe that the early atmosphere
was:
- Rich in carbon dioxide and water vapor
- Lesser amounts of carbon monoxide, nitrogen,
hydrogen, and hydrogen chloride
- Trace amounts of ammonia and methane
- 3.5 billion years ago, the composition began
to change to the present composition of mostly nitrogen
& oxygen.
- First due to carbon dioxide dissolving in seawater
to form carbonic acid, then combining with crustal
rocks
- 2 billion years ago, the ancestors of green
plants began releasing more oxygen into the atmosphere
- The Origins of Life
- 1953 - Stanley Miller mixed together water
vapor, ammonia, methane and hydrogen and ran an
electric spark through the mix for a week.
- Produced a number of amino acids and other
organic compounds.
- Recent research now suggests that simple organic
compounds were brought to Earth on comets, meteors,
and asteroids that crashed into the Earth during
its birth.
- So where did life originate?
- Not completely sure, but evidence suggests
that all life originated in the oceans.
- Biosynthesis - The initial formation
of life on Earth
- The first self-sustaining molecules may have
formed deep below the layers of ice near hydrothermal
vents.
- When did life begin?
- Oldest fossils are cyanobacteria from NW Australia
and are 3.4 - 3.5 y.o
- Stromatolites are colonial structures formed
by photosynthesizing cyanobacteria and other microbes
The Nature
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Origins & The Formation Of The Universe
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