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A review of:. The Formation and Evolution of the Universe!. The BIG BANG. ~14 Billion years ago Dense, hot, tiny, massive point in space Exploded Universe expanded to its current state, and is still expanding due to the force of that explosion. - PowerPoint PPT Presentation
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A review of:
~14 Billion years agoDense, hot, tiny,
massive point in spaceExplodedUniverse expanded to its
current state, and is still expanding due to the force of that explosion. It is also still cooling from
this hot, violent eruption.
First few seconds all matter was created Atoms could not form at first since it was
TOO hot. Particles were all moving too fast
Cooling led to the formation of atoms / molecules within 300,000 years after the Big Bang
Only formed Hydrogen, small amounts of Helium. All Hydrogen of the universe was formed at
that time.
1 Billion years later…Formed in areas where there were
large amounts of interstellar matter Dust and Gas
Temperature needs to be high enough for FUSION to occur. Side Note: Fusion
▪ E=mc2
▪ 4H→1He + ENERGY▪ Continues to form heavier elements
Large stars can produce heavier elements Eventually the stars EXPLODE (more on
this later) in a supernova All of the elements created were
RELEASED into space Responsible for the formation of all
elements in the periodic table Our sun has traces of heavy elements in
it, thus it must be AT LEAST a 2nd generation
Formed ~ 10 billion years ago
Spiral galaxy Cluster of stars, matter,
and other celestial objects that are gravitationally bound and rotate around the center of a massive black hole.
Nebular Theory Rotating disk of dust
and gas Hottest at the center
(what formed here??) Formed on one of the
spiral arms of the galaxy IMPORTANT! (more on this later)
~5 billion years ago Eight planets formed
Inner (Rocky) planets Outer (Jovian / Gaseous) planets
Formed 4.6 billion years ago
Middle of solar system Densest collection of
matter Hottest temperatures
Collection of gas / dust that contracted until fusion began (more on this later)
T-tauri phase 4.5 billion years ago (IMPORTANT!)
“shedding” phase Particles swept out by solar
wind to furthest parts of the solar system
Which would travel further – lighter particles, or heavier particles?
Take a look at the periodic table – which particles would be lighter?
The T-tauri phase determined the composition of the 8 planets
http://upload.wikimedia.org/wikipedia/commons/8/8e/Hs-2000-32-a-animated_gif.gif
Reached current size 4.4 billion years ago Mercury, Venus, Earth, Mars Similar compositions, structures
All have a core, mantle, and crust region (the structure of the Earth will be covered in more detail in a later unit)
High density Rocky, metallic, heavier elements Smaller
Formed from planetary accretion, planetesimals
Reached current size 4.4 billion years ago Jupiter, Saturn, Uranus, Neptune Gaseous Giants / Jovian Planets Similar composition / structure
Possibly rocky / solid cores? Lighter, gaseous elements Largely composed of H & He, especially their atmospheres
(which also accounts for most mass in the solar system) – would that be expected?
Properties of the planets / solar system will be discussed in the next unit
Earth’s moon formed 50,o00 years after Earth COLLISION THEORY for formation Evidence:
Identical compositions More details on the moon next unit!
Earth’s core formed 4.35 billion years ago Kinetic energy from accretion
→ heat energy Radioactive decay →heat energy
▪ An aside on radioactive decay (discussed further later)……▪ What is it?
▪ Earth’s internal heat energy source!
▪ Leads to a lot of volcanism (which in itself is important because it renews the land / soil / nutrients) Atmosphere becomes rich in CO2 and H2O
Earth becomes molten!▪ Heavier elements: sink (Iron and Nickel)
▪ Created a magnetic field around Earth that protected us from the Sun’s harmful rays, and other high energy particles from space, which protects life.
▪ Aurora belts / Northern Lights
▪ Lighter elements: float to the top (Nitrogen, Carbon)▪ These elements are ESSENTIAL for life, so this process
was CRUCIAL in the development of life on Earth!!
Early Atmosphere (4.4-4.0 bya)▪ Light elements (H, He, methane), H2O and others
▪ Lightest elements escaped to space
Secondary Atmosphere (4.0-3.3 bya)▪ Dominated by gases released in volcanic eruptions (CO2,
H2O, N2)▪ Condensation (due to cooler temperatures)leads to most
H2O precipitating out to form oceans
Primary Atmosphere (3.3 bya - present)▪ Evolution of life / plants leads to photosynthesis
▪ Atmosphere becomes rich in O2, less CO2 (some fluctuations through the years)
Evolution of Earth’s Atmosphere
Believed to have formed from: Continued rain (so much water vapor in the
atmosphere from all of the volcanic activity lead to a lot of condensation!)
Impacts of icy meteors / comets, whose water melted.
Not entirely sure, however. Oceans harbored and fostered life. The
first advanced life forms developed in the ocean. Eventually, life made the leap from ocean to land, but we can thank the oceans for allowing us safe haven while the land was going through such a chaotic time!
All molten at first Due to frequent volcanic eruptions, land
was constantly being renewed; surface was constantly changing▪ Rapid changing environment and climate led to
mass extinction and the birth of many new species in short periods of time
Oldest rock known on Earth formed 3.8 bya Stable continents first formed 2.5 bya
▪ NOT Pangaea (200 mya) -Gondwana & Laurasia; formation of Appalachian Mountains
Land on Earth
Bacteria developed 3.9 – 3.5 billion years ago (not sure how)
Development of plant life is CRUCIAL – why? Photosynthesis!
▪ Turns CO2 into O2! ▪ Developed oxygen rich atmosphere (~20%) 3 billion years
ago▪ Allows life to exist on Earth!!
Extinction of dinosaurs from impact 65 mya Mammals survive, and leads to our evolution
and domination! Otherwise, the reptiles might still be in charge!!
1st humans appear 200,000 years ago
Hadean (Earth forms - 3.8 bya)▪ Atmosphere evolves, oceans begin to form
Archean (3.8-2.5 bya)▪ Life develops, O2 rich atmosphere develops▪ Oldest known solid rock develops
Proterzoic (2.5 bya - 542 mya)▪ Stable continents appear
Phanerozoic (542 mya - present)▪ Multicellular life evolves, life moves onto land from the
sea Precambrian - 1st 3 eons, before multicellular life
Earth’s Eons