GEO 101 Lecture Notes - Lecture 3: Star System, Hadean, Paleozoic
21 Feb 2018
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Department
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Geologic Time- The span of time since Earth’s formation
• Earth and Moon are both 4.6 billion years old
The Universe-
• Geocentric Theory-the earth is in the center of the Universe
• Heliocentric Theory- the Sun is in the center of the Universe
Cosmic Systems-
• Star system- a group of one or more stars, with planets
orbiting them (solar system)
• Galaxy- a massive group of millions of star systems (milky
way)
• Universe- includes billions of galaxies
The Big Bang Theory
• Occurred 14 billion years ago
• All matter/energy was packed into one point-violently
exploded
• Led to creation of elements
• Evidence Supporting
o Galaxies appearing to be moving away from each
other
o We are still “cooling down”
o The availability of “light elements”
• Nebular Hypothesis- Nebular Disk Model
o Stars from massive and dense clouds (nebulae) of
hydrogen gas
o Slowly rotates, gradually collapses and flattens due to
gravity
o Planets form on the disk
Earths Interior- earth was liquid rock, starts cooling down, forming
layers of earth
• Inner Core (solid), Outer Core (liquid made from iron), mantle
(behaves like rubber), crust (solid, rigid rock material),
atmosphere
o How do we know?
▪ Earthquake monitoring
The Earth’s History
Specific Events/Changes during each Era-
• Paleogeography- continental configuration
• Life Evolution
• Other important events- climate change
Precambrian: 90% of Earth’s History
The Hadean Eon- The Birth of Earth
• Matter accumulates and compacts into a dense ball
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Geologic time- the span of time since earth"s formation: earth and moon are both 4. 6 billion years old. The universe: geocentric theory-the earth is in the center of the universe, heliocentric theory- the sun is in the center of the universe. Cosmic systems: star system- a group of one or more stars, with planets orbiting them (solar system, galaxy- a massive group of millions of star systems (milky way, universe- includes billions of galaxies. Earths interior- earth was liquid rock, starts cooling down, forming layers of earth: inner core (solid), outer core (liquid made from iron), mantle (behaves like rubber), crust (solid, rigid rock material), atmosphere, how do we know, earthquake monitoring. Specific events/changes during each era: paleogeography- continental configuration, life evolution, other important events- climate change. Earth"s moon: atmosphere develops, the earth starts cooling down, hard rock solidified, water condensed, oceans formed, no life yet!
