Earth and Solar System

I.Formation of the Universe. A.Big bang is the most commonly accepted theory. 1. Supported by evidence that Galaxies are moving away from one central point.

2. All matter and energy in the universe was condensed to one small point at the center of the cosmos. 3. Bang.

II.Formation of Solar System. A.Nubular Hypothesis – As gas and matter from a nebular cloud condensed (via supernova explosion), the sun formed. 1. Most original matter was Hydorgen and Helium.

2. Eddies of matter (like in a river) around the sun formed into 8 planets.

3. The inner planets are missing High concentrations of Helium and Hydrogen. a. Perhaps do to solar wind and evaporation during early, hot stages of development. Venus: 864°FMercury: -340°- 788°F

III. Earth A. Density and Density Stratification 1. Density is essentially how heavy something is for it’s size. 2. Density determines the position of materials in the earth’s layers (Density Stratification).

3. Chemically earth is divided into Crust, Mantle and Core. a. Crust – low density Silicate minerals b. Mantle – high density iron and magnesium silicate rock. c. Core – Iron and Nickel

4. By Physical Properties divided into 5 layers. a. Inner core (rigid, 3200 to 3960 mi. under surface) b. Outer core (Liquid, 1800 – 3200 mi. under surface)

c. Mesosphere- (rigid, 430mi under surface to 1800mi) d. Asthenosphere (plastic, 62mi under surface to 430mi). e. Lithosphere (rigid crust, surface to 62mi.)

5. Clastic rocks, named for their particle size, (sedimentary). a. Describe sedimentary environment in which they were deposited. b. If undisturbed, younger sedimentary layers are higher (on top) of the stack.

6.Additionally, plant and animal fossil remains can be used to determine the Relative Age of rock. 7.Using radioactive isotopes can be used to determine the Absolute age of rock.

B. Ocean crust vs. Continental crust. 1. Oceanic crust a. Primarily made of Basalt b. Higher density than continental crust.

2. Continental Crust a. Primarily made of Granite/basalt. b. Lower density than oceanic crust. c. Is thicker than Oceanic crust.

IV. Creation of earth’s atmosphere and oceans. A. After original gasses were blown away (solar winds), Outgassing formed new atmosphere. 1. Caused by volcanoes, geysers and hot springs.

2. This left the first atmosphere consisting of carbon dioxide, water vapor, sulfur dioxide and methane. 3. Later atmosphere due to interaction with life.

B. Origin of the oceans. 1. Distance from the sun allowed water vapor to become acid rain (mixed with carbon dioxide and sulfur dioxide), eventually forming early oceans. 2. The first oceans developed about 4 billion years ago.

3. Dissolving minerals from rocks (weathering and river bottoms), volcanic activity, and erosion of the continents led to the salinity of the oceans.

C.Did life originate in the oceans? 1. One proposal is that building blocks of life arrived on a meteor. 2. Another proposes life originated around hydrothermal vents. 3. Another proposes minerals under the earth interacted chemically to produce these building blocks.

4. There is very little in the fossil record 3800mya to guide us. *However radiometric dating of stromatolite indicate they were around 3.5bya

D. Stanley Miller Mixed CO2, methane, ammonia, hydrogen and water (early atmosphere). -added UV light and electrical spark (lightning).

-a multitude of organic compounds including amino acids were formed. ***an example of how first life probably began.