Guided Notes Ch. 27 Planets
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Name: _____________________________________ Date: __________________ Period: __________ CHAPTER 27 GUIDED NOTES – THE PLANETS Chapter 27.1 Formation of the Solar System Objectives: Explain the nebular hypothesis of the origin of the solar system Describe how the planets formed Describe the formation of the land, the atmosphere, and the oceans of the Earth The Solar System Consists of the Sun, the planets and other bodies that revolve around the Sun Planet = any of the primary bodies that orbit the Sun How Did the Solar System Form? Pierre-Simon, marquis de Laplace came up with the nebular hypothesis ________________ = rotating cloud of gas and dust Nebular Hypothesis 5 billion years ago Matter gathered into a nebula cloud Gravity near cloud increased due to a nearby supernova ___________________________________ Nebular Hypothesis, Cont’d Within nebula cloud: _________________________________________ Pressure from gravity caused center of nebula to become extremely hot Hydrogen fusion began Sun formed 1 Planet Formation While Sun was forming in center of nebula… planets were forming in outer regions of nebula ____________________ = small body from which a planet began Planetesimals collided to form protoplanets Protoplanets = _______________________________________ Collides Planetesimal Condenses into Protoplanets Planets Planetary Characteristics Depend on distance from the Sun Inner Planets a.k.a. _____________________________ Mercury, Venus, Earth, Mars Outer Planets a.k.a. “Gas Giants” Jupiter, Saturn, Uranus, Neptune Inner Planet Formation 4 planets closest to Sun __________________________________________ Contained large % of heavy elements Iron and Nickel Lost less dense gases due to extreme heat and Sun’s radiation Inner Planet Formation, Cont’d Denser material sunk to center of planets Less dense material became surface Inner Planets: _____________________________________________ 2 Outer Planet Formation Next four planets Jupiter, Saturn, Uranus, Neptune Formed in colder regions of solar nebula Cold temp Did not lose light elements _____________________________________ Kept their ices Water ice, Methane ice, Ammonia ice Outer Planet Formation, Cont’d Eventually, _________________________________ From interior heat Formed layers of thick liquids and gases Outer Planets known as the _________________________________ Outer Planets: composed mostly of gas, low density, HUGE planets What About Pluto? Pluto: Ice ball made of frozen gases and rock Other objects similar to Pluto have been discovered recently None of these objects are larger than Pluto Pluto may be one of these objects Some astronomers do not classify Pluto as a major planet _________________________________ 3 Formation of Solid Earth Earth had extreme heat Dense materials melted and formed core ________________________________ Less dense materials formed outer layers Mantle Thick, middle layer Iron and Magnesium-rich rock Crust ________________________________ Silica-rich rock, less dense Process of layer formation = ______________________________ Formation of Earth’s Atmosphere Less dense gas molecules rose to surface Original atmosphere: Hydrogen and Helium Gravity could not hold them to Earth’s atmosphere Blown away by solar wind A New Atmosphere Due to _________________________________ Volcanic eruptions releasing large amounts of gases Water vapor ______________________________________ Nitrogen Methane Sulfur dioxide Ammonia Created __________________________ layer (O3) Shielded Earth from Sun’s UV radiation 2 billion years ago, Oxygen increased rapidly Atmosphere became similar to present one 4 Formation of Earth’s Oceans Ocean water May have come from __________________________________________ Became part of atmosphere As Earth cooled, water vapor condensed to form rain First oceans From collected rain freshwater Over millions of years, rain dissolved rock Dissolved rock carried back to oceans Combined with atmospheric chemicals Formed salts ________________________________ Salt is harvested for human use from oceans Oceans and the Atmosphere Oceans affect _______________________________________________ Oceans dissolve CO2 from atmosphere Current atmosphere has more CO2 than previous atmosphere Previous atmosphere had lower CO2 levels Early global climate was probably __________________ than today’s global climate Chapter 27.2 Models of the Solar System Objectives Compare the models of the universe developed by Ptolemy and Copernicus Summarize Kepler’s 3 laws of planetary motion Describe how Newton explained Kepler’s laws of motion Early Models of the Solar System Aristotle – geocentric solar system, 2000 years ago __________________________ Sun, stars, planets revolve around Earth Did not explain retrograde motion Ptolemy – epicycles, 130 CE Planets move in epicycles as they revolve around Earth Epicycle = _______________________________________ Epicycles explained retrograde motion (apparent backwards motion) Epicycle Motion - Ptolemy 5 Early Models of Solar System, Cont’d Copernicus – heliocentric, 1543 CE Sun-centered Planets revolved around Sun At different speeds and distances from Sun Fast-moving planets passed slow-moving planets Explained ___________________________________________ Galileo – 1610 CE Discovered Jupiter’s _________________________________ Objects can revolve around other objects Early Models of Solar System, Cont’d Kepler and Brahe, circa 1601 CE Tycho Brahe made observations of the night sky Brahe had the best observatory in Europe After Brahe’s death, his assistant, Johannes Kepler, discovered patterns in Brahe’s work These patterns developed Kepler’s laws of __________________________________________ Kepler’s 3 Laws of Planetary Motion Law of Ellipses Law of Equal Areas Law of Periods Sir Isaac Newton Circa 1679 Newton wanted to know why planets moved in the ways that Kepler described He hypothesized that a moving object will remain in motion until an outside force acts on it Known as _________________________________ 6
