Chapter 29 Our Solar System-Planet Overview Objectives 1. Describe early models of our solar system. This means I can: a. Explain the geocentric

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1 Chapter 29 Our Solar System-Planet Overview Objectives 1. Describe early models of our solar system. This means I can: a. Explain the geocentric model of the solar system and how retrograde motion brought change to that model. b. Describe the contributions and changes to solar system arrangement due to the following scientists: Nicolaus Copernicus, Kepler, Isaac Newton, Tycho Brahe, Galileo. 2. Examine the modern heliocentric model of our solar system. This means I can: a. Explain Kepler s 1 st Lae and its relationship to the following terms astronomical unit, perihelion, aphelion, focus, major axis, semi-major axis, the Sun, and eccentricity. b. Determine the relative shape (elongated oval, oval, circle) of an orbit when given its eccentricity value. c. Explain Kepler s 2 nd and 3 rd Laws. 3. Relate gravity to the motions of celestial bodies. This means I can: Describe how mass, center of mass, and distance between 2 objects affects their gravitational pull on each other. 4. Compare and contrast the properties of the terrestrial planets. This means I can: a. Name the terrestrial planets in order, beginning with the one closest to the sun. b. Identify the planet that has a given unique characteristic such as: highest amount of atmospheric CO2, highest amount iron on surface, largest temperature range, red color, greenhouse effect, number of moons, largest canyon, largest mountain, cratered like the Earth s moon, surface features suggesting liquid water was once present, thick vs. thin atmosphere, etc. (See planet summaries written after each planet project presentation.) 5. Compare Earth with the other terrestrial planets. This means I can: a. Identify the planet most like the Earth in mass, diameter and density. b. Define precession, explain its cause, and describe how it affects the north star. 6. Describe the properties of the gas giant (Jovian) planets. This means I can: a. Name the gas giant (Jovian) planets in order, beginning with the one closest to the sun. b. Compare and contrast belts and zones, and identify which planets have them. c. Identify the planet that has a given unique characteristic such as: rapid rotation, brightest rings, large storm, largest planet, blue color & what causes the color, flattened, etc. (See planet summaries written after each planet project presentation.) 7. Compare & contrast terrestrial vs. gas giant (Jovian) planets according to the properties listed in Objectives #4 & 6 above. In addition, I can: a. Label a diagram, identifying the location of the 8 planets, Pluto and the asteroid belt. b. List the planets that have retrograde rotation. c. Discuss defining general characteristics of each category such as: relative size of planets, 2 main elements present in each category, density, type of surface, relative number of moons, presence of rings, belts, zones 8. Identify the unique nature of the planet Pluto. This means I can: a. Explain why Pluto is no longer classified as a major planet. 9. Summarize the properties of the solar system that support the theory of the solar system s formation. Describe how the planets formed from a disk surrounding the young Sun. I can: a. Define & describe how the following terms are involved in the theory of the solar system s formation: interstellar cloud, solar nebula, planetesimal, equatorial plane. b. Explain how the theory is supported by the types of elements and density differences of the inner terrestrial vs. outer gas giants. c. Using distance from the sun and resulting temperature differences throughout the solar system, explain why lightweight gases such as hydrogen and helium are rare in the terrestrial planets but common in the gas giants. 10. Explore remnants of solar system formation. This means I can: a. Define asteroid. Identify the location of the asteroid belt on a solar system diagram. b. Differentiate between meteor shower, meteoroid, meteor, and meteorite. c. Label, define and describe the composition of the parts of a comet including: coma, nucleus, tail, head. Describe how, when, and why the tails are formed, and which direction they point. d. Discuss the location of the two main clusters of comets, including how far they are from the sun in astronomical units. ES Ch 29 Solar System Note Outline - 1-5/24/2012

2 Overview of solar system: 1. All planets orbit Sun is same direction Between 4 & Planet (Is it a planet? Major or minor?) Mnemonic 2. All orbits except lie near the same plane 3. Planets move faster at perihelion than aphelion due to Sun s 4. Planets closer to Sun move Terrestrial Planets: The 4 inner planets, closest to the Sun Solid rocky surfaces Close to size of Earth Sometimes called the planets due to iron & nickel cores Mercury (1 st )) 1. No moon 2. Rotates 1½ times in 1 orbit, therefore only 3 days occur every 2 years 3. Little atmosphere 4. Surface similar to moon: craters, (like maria) & scarps a. Scarps = planet wide system of b. Hardened plains suggest planet was once volcanic 5. Most extreme (largest difference) day vs. night temperature in solar system a. Daytime temp: b. Nighttime temp: 6. Thick core of & ES Ch 29 Solar System Note Outline - 2-5/24/2012

3 Venus (2 nd ) 1. Nicknames: a. Earth s sister planet-why? b. Morning or evening star- Why? 2. Highest of any planet, 75% 3. No moon 4. Slow rotation: 1 Venus day = Earth days 5. Hottest planet due to a. Results in a b. Main gases: 96% & 3% i. Also contributes to the c. Average surface temp is 464 o C 6. Unique clouds made of 7. High atmospheric pressure 8. spin opposite of most planets A. This backward spin is called B. If on Venus, Sun would rise in the and set in the 9. Surface: Smooth due to flows a. Very few impact craters 10. Interior: Probably similar to Earth s: Earth (3 rd Rock from the Sun!!) 1. 1 moon 2. Unique-Water in 3 phases:,, & a. Essential for life 3. Atmosphere: a. Dense b. Atmospheric gases & c. Mild greenhouse effect keeps temp needed for life 4. Tilted axis combined with revolution creates a. Wobble on its axis like a top is called i. Due to Moon & Sun s gravitational pulls ii. See Fig p783 ES Ch 29 Solar System Note Outline - 3-5/24/2012

4 Mars (4 th ) 1. Nickname: The Red Planet a. Caused by high content in soil 2. 2 moons-phobos & Deimos 3. Atmosphere a. Thin, so little greenhouse effect b. Turbulent, constant winds c. storms may last for weeks 4. Surface a. Northern hemisphere: i. Mostly ii. Largest in solar system named b. Southern hemisphere: c. Other features: i. Dried river beds suggest water once ii. Polar ice caps shrink & grow w/seasons caused by & Both caps made of dry ice or frozen May have frozen water underneath 5. Interior: Solid core of,, & Asteroid belt 1. Left over planetary debris from solar system formation, that never formed planets 2. Located between Mars & Jupiter 3. Separates terrestrial planets and gas giants Gas Giants or Jovian Planets 1. Interiors are either gaseous or liquid, resulting in low density 2. Lack solid surfaces 3. Composed mainly of lightweight elements such as,,,, and 4. Cold at surface 5. Many satellites 6. Ring systems 7. Large in size and mass compared to Earth 8. Most gas giant planets have similar to those on Earth, but due to the of the planet, the clouds get stretched out into. 9. Clouds of the gas giants are made of,,, and, rather than water vapor. ES Ch 29 Solar System Note Outline - 4-5/24/2012

5 Jupiter (5 th ) 1. Largest planet 2. Its mass contains 70% of mass in the solar system 3. Fastest rotation ( ) in solar system, hours a. Spins so fast that the planet at equator & is not perfectly b. 7% wider around equator than the poles 4. 4 Galilean moons:,,, & a. Io-constant volcanoes b. Europa-subsurface water ocean c. Plus several smaller ones 5. Atmosphere a. Mainly & b. Bands of clouds 1. Belts- low, warm, dark clouds 2. Zones-high, cool light colored clouds c. Giant Red Spot 6. Has rings 7. Layers a. Outer-liquid hydrogen b. Inner layer of metallic hydrogen c. Core-heavier elements Saturn (6 th ) 1. 2 nd largest planet 2. Similar to Jupiter-rotates rapidly & has belts & zones 3. Atmosphere a. Mainly & b. Also has & 4. major rings a. Made of rocks & ice b. Hypothesis that rings formed from debris after a 5. 1 major moon called plus at least more moons a. Titan-atmosphere made of & Uranus (7 th ) 1. At least moons & rings 2. Tilted on axis, so that poles lie in orbital plane 3. Cold, average temp is degrees Celsius 4. Like Venus, has motion ( spin ) 5. Atmosphere a. Mainly & 6. Dark rings b. But, appears due to gas which reflects blue light ES Ch 29 Solar System Note Outline - 5-5/24/2012

6 Neptune (Usually 8 th, but sometimes 9 th if Pluto is still considered a planet) 1. Presence predicted prior to discovery because of a in Uranus 2. 8 moons Most famous is which has thin atmosphere & geysers 3. Atmosphere Like Uranus, appears due to Like Jupiter & Saturn, has & Like Jupiter, HAD a large storm called the 4. rings made of microscopic particles Pluto (Used to be the 9 th major planet, but it was sometimes the 8 th ) 1. Different from other 8 planets 2. Surface: rock & ice 3. Atmosphere & 4. Like Venus & Uranus has ( spin ) 5. Scientists have long questioned if it is really a planet: a. Very small b. Very eccentric orbit, causing Pluto to be closer to Sun at than Neptune i. 50 AU from Sun at & 30 AU at ii. For comparison, 1 AU = iii. Therefore, Pluto is between to times farther from the Sun, than the Earth c. Large moon Charon-are they really a double planet? d. Was Pluto originally a of e. Or is it a or planet instead of a major planet? 6. Member the Kuiper Belt: a. Group of objects that orbit in a zone beyond Neptune s orbit b. Icy objects with diameters of at least 1,000 km c. May be source of comets d. Is Pluto a comet? Intelligent Life: 1. Mars 2. Europa icy surface, but could contain watery slush underneath 3. Titan - evidence of methane lakes 4. Io volcanic activity might sustain life, but there is an absence of water ES Ch 29 Solar System Note Outline - 6-5/24/2012

7 Section 29.4 Formation of Solar System Collapsing Interstellar Cloud Theory - Solar System Formation 1. A cloud of that stars & planets are formed from 2. Consists mainly of & gas 3. Condenses due to & concentrates to form stars or planets 4. As it condenses, the cloud, becomes like a disk, and 5. Solar nebula: Large cloud that collapsed & formed the a. Center, at edges of disk b. Temp difference caused different gases to condense in different areas i. became close to Sun, before spreading out ii. Lighter elements ( ) remained gas until further away from Sun c. Therefore, planets are made of dif elements 6. Planetesimals: space objects built by solid particles a. Condensing particles become & 7. Planets- planetesimals collide & become planets a. was 1 st to form in outer solar system i. As size increased, gravity ii. Then more gas, dust pulled in & growth continued b. Rest of gas giants form i. Not as large because had taken much of the material c. Satellites ( ) form along equatorial planes d. Inner planets: metals so they are & i. Sun s pulled much of the material, so closet planets have moons 8. Debris- (leftover material) a. Most crashed into planets or ejected out of solar system b. Planetesimals left between Jupiter & Mars = i. prevented them from merging into a planet 9. Asteroids- rocky bodies from solar system formation that the Sun a. Meteoroid- piece of asteroid (interplanetary material) that atmosphere i. Produces a meteor- a streak of as it up in the atmosphere ii. Meteorite- piece that completely & the ground, leaves a crater until it erodes ES Ch 29 Solar System Note Outline - 7-5/24/2012

8 10. Comets- Small bodies made of & that have orbits around the Sun a. Most found in 1 of 2 clusters: i. -close to Pluto (30-50 AU) from Sun ii. Oort cloud- >100,000 AU from Sun b. Comet Structure (Parts of a comet): i. Icy nucleus = small, When heated, releases gas & dust to form the other 2 parts ii. Coma surrounding nucleus iii. Tail-always points from the Sun due to solar iv. Head = nucleus & coma c. Meteor shower - occurs when Earth passes through remains of a Section 29.1 Early Astronomers Research & Ideas 1. Ancient astronomers could recognize the difference between stars & planets a. Planets move relative to star positions 2. Geocentric Model- 1 st model of solar system a. Believed the Sun, planets & stars a stationary b. Problems- didn t explain why some planets appeared to move ( motion) i. Most move planets appear to move from ii. But sometimes they appear to move 3. Heliocentric Model- -centered a. Suggested by Copernicus in 1543 b. Explained retrograde motion i. Inner planets move, so outer planets appear to move 4. Galileo s discoveries also support heliocentric a. 4 moons orbit, not the Earth 5. Kepler s 1 st Law: Planets orbit the Sun in an ellipse, NOT a circle a. Ellipse = oval: centered on points (foci), not 1 like a circle i. is always one focus for all planets ES Ch 29 Solar System Note Outline - 8-5/24/2012

9 b. Eccentricity- HOW oval-shaped. Based on the between the 2 i. Has a value between 0 to 1 0 = perfect (Distance between the 2 foci is ) 1 = very ii. Planet is NOT at a constant distance from the Sun iii. Perihelion- point to the Sun iv. Aphelion- point c. Major axis: runs through both foci i. Is the diameter d. Semimajor axis: of major axis i. Is the planet s distance to Sun e. 1 AU (astronomical unit) = the average distance between 6. Kepler s 2 nd Law: Planet sweeps out equal amounts of in equal amounts of a. See Fig 29-4 p Kepler s 3 rd Law: Math equation to determine the size of a planet s orbit & the time it takes to orbit 8. Gravity & Orbits a. Newton s Law of Universal Gravitation i. Any 2 bodies each other ii. Amount of gravity depends on their & their apart iii. Orbit is around the of mass of the 2 bodies (Sun & planet) 1. Sun is the center of the orbit but is 1 of the 2 iv. Fig 29-5 p779 ES Ch 29 Our Solar System Review for Test 1. To study-notes, worksheets, book (vocab, questions, diagrams), 2. Computer Review: Then: Chapter Resources, Unit 8, Chapter 29 ES Ch 29 Solar System Note Outline - 9-5/24/2012