1	Building a Planet Chapter 1
2	Scientific Method A general research strategy based on the principle that every physical event has a physical explanation. It involves: Collection of data By observation, by experimentation.. Formulation of Hypothesis (working model) Testing and modification of hypothesis Theory (or Principle or Law) A hypothesis that has survived repeated challenges and is supported by a substantial body of data
3	Geology Geology = Geos (earth) + logus (science) It evolved mainly as an observational science Much of the present understanding of geology is based on the Principle of Uniformitarianism (or “Present is the key to the Past”) Geological processes that we see in work today have worked much the same way over geological time
4	Cosmogenesis Big Bang (13.5 billion years ago) The Universe started with a cosmic explosion. Before the Big Bang all matters were condensed in an single, infinitely dense point. All matters in the Universe are expanding away from the center of explosion ever since
5	"Formation of Nebula" Formation of Nebula Rotating clouds of gas and dust
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12	Formation of the Solar System Proto Solar Nebula: Flattened disk of condensed matter Intense Pressure and collisions heated the proto Sun to millions of degrees which started nuclear fusion Formation of the solar system (4.6 – 4.5 Ga) Planetesimals: kilometer sized chunks of aggregated matter Inner and Outer Planets Planets closer to the sun (Mercury, Venus, Earth and Mars) lost most of the volatiles becuause of intense heat from the Sun. These are the Inner Planets The volatiles condensed in planets farther out (Jupiter, Uranus, Saturn, Neptune)
13	"Early heating and melting of..." Early heating and melting of Earth Impacts, compression, radioactivity Some speculate the a body twice the size of Mars hit Earth <20 Million years after Earth’s formation The impact melted most of the earth and ejected debris in space which aggregated to form the Moon and tilted Earth’s axis of rotation Earth’s age is approximately 4.53 Ga, oldest Moon rock is 4.46 Ga old, oldest meteorite is 4.56 Ga old
14	Differentiation of the earth Once melted, lighter materials rose towards the surface and formed the crust Denser materials sank to the center of the Earth and formed the core The layer in-between is called the mantle The segregation of Earth in different layers is called Differentiation
15	Abundance of Elements 2/3rds of the Earth is made of Iron and Oxygen only. Only 4 elements make up 90% of Earth 3/4^th of the crust is made of Oxygen and Silicon only.
16	Structure of the Earth Core: 6370 – 2900km: Iron and Nickel Inner Core: Solid (6370 to 5150 km) Outer Core: Liquid (5150 – 2900 km) Mantle: Iron, Magnesium, Silicon, Oxygen Lower Mantle: 2900 to 250 km Asthenosphere(partially molten): 250 km -100 Upper Mantle: 100 to ~40 km Crust: 40 – 0 km: Silicon, Oxygen, Aluminum Continental(35-40 Km), Oceanic(5 km)
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25	Features of Divergent Margin Mid Oceanic Ridge-Rift Shallow Focus earthquakes High Heat Flow New Sea floor being created: Basaltic volcanism
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29	Features of Convergent Margin Subduction Zone Shallow, Intermediate and Deep Focus earthquakes: Benioff Zone Deep Sea Trench Arc Volcanism: Andesitic to Rhyolitic Collisional mountain belts