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44 Cards in this Set
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Comparative Planetology |
: the approach of comparing and contrasting planets to identify principles and understand planets better
*We use Earth as a standard for comparative planetology b/c we know its best and it contains all the phenomena found on the other Terrestrial planets |
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The Terrestrial Worlds |
-Differ in Size
ALL HAVE: 1) Low-density crusts 2) Mantles made of dense rock 3) Metallic cores |
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Terrestrial Planets |
include: Earth, the Moon, Venus, & Mars
*moon is included b/c it is a complex world and makes a striking comparison to Earth |
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Comparative Planetology: Key Points |
1) Cratered surfaces are old
2) Heat flowing out of a planet is what drives geological activity
3) The nature of the planet's atmosphere depends on the size of the planet and it's temperature
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4 Stages of Earth's Evolution |
1) Differentiation: the separation of material into layers according to density 2) Cratering: after a solid surface has formed, heavy bombardment of the early solar system made craters 3) Flooding: by lava and water 4) Slows Surface Evolution: constant changing sections of crust slide over and against each other |
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Seismic Waves |
: Vibrations caused by earthquakes and are detected by seismographs |
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Pressure Waves |
: waves that can pass through a liquid, such as sound |
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Shear Waves |
: travel as a side-to-side vibration and cannot pass through liquid |
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Earth's Structure |
-4.6 billion years old and happened from the inner solar nebula -Core: liquid (we know that b/c seismic waves don't travel through it) and composed of iron and nickel -Mantle:plastic-like and can deform and flow under pressure -Crust: brittle and breaks under stress |
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Primary Atmosphere |
: Earth's first atmosphere that was composed mostly of carbon dioxide, nitrogen, and water vapor |
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Secondary Atmosphere |
: current atmosphere, seawater absorbed most of the carbon dioxide and plants have added oxygen |
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Greenhouse Effect |
: process by which carbon dioxide in the atmosphere traps heat and raises the temperature of the planets surface |
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Ejecta |
: debris blasted out of craters
*can produce rays and secondary craters |
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Multiringed Basins |
: very large pits formed by large impacts |
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Micrometeorites |
: tiny and constantly bombard the Moon's surface |
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the Moon's Surface |
Highlands: oldest part of surface and heavily cratered Lowlands: filled by lava, causing it to be smooth maria |
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Lunar Rocks: Vesicular Basalts |
: lava-made rocks that contain holes and bubbles |
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Lunar Rocks: Anorthosite |
: light-colored and low-density rock that floated to the surface of the highlands when it was a magma ocean |
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Lunar Rocks: Breccias |
: rocks made of fragments of broken rock cemented together under pressure |
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Mercury |
-smaller than Earth (1/3 of Earth's diameter) -larger than the Moon -old, heavily cratered surfaces -extremely thin atmosphere -very high density (metallic core is large compared to its diameter) -Lobate scarps |
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Lobate scarps |
: long curving cliffs formed by a wrinkling crust, which forms when it's large metallic core solidifies and contracts |
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Venus |
-almost as large as Earth -can't be seen from Earth b/c of the atmosphere -CO2 in atmosphere drives and intense greenhouse effect and makes the planet a world of Volcanoes and lava flow -Slightly closer to the sun than Earth -Shield Volcanoes -Geological activity due to volcanism and vertical tectonics -Coronae: large circular uplifted regions |
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Shield Volcanoes |
-found on Earth, Venus, and Mars -Caused by rising columns of magma (hot spots)
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Composite Volcanoes |
-only found on Earth -associated with plate tectonics and subduction zones |
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Mars |
-1/2 size of Earth -thin atmosphere -cold and has low escape velocity -air pressure is too low for water >liquid water would boil away >remaining water is frozen in polar caps and as permafrost in the soil -water-related features: >outflow channels: appear to have been cut by massive floods >valley networks: long-term drainage caused riverbeds with sandbars, delta, and tributaries -has 2 moons (Phobos & Deimos) |
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Jovian Planets |
-large, massive low-density worlds in the outer solar system -Includes: Jupiter, Saturn, Uranus, Neptune |
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Belt-zone Circulation |
: cloud belts parallel to the planet's equator |
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"Liquid Giants" |
Jupiter and Saturn are composed mostly of liquid metallic hydrogen |
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"Ice Giants" |
Uranus and Neptune are abundant in solid water |
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Jovian Satellite Systems |
*all Jovian worlds have extensive satellite systems classified as: Regular Satellites-large, close to parent planet, move in prograde direction (with rest of the solar system) Irregular Satellites-small, far from parent planet, have high orbital inclinations |
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Jupiter |
-core made of heavy elements surrounded by a deep mantle of liquid metallic hydrogen (large and strong magnetic field) -Magnetosphere: around Jupiter; traps high-energy particle from the sun to form intense radiation belts -Atmosphere:3 layers of cloudes formed of hydrogen-rich molecules -Moons: Galilean moons -Ring -Roche Limit |
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Jupiter's Magnetosphere |
-around Jupiter -traps high-energy particle from the sun to form intense radiation belts |
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Jupiter's Atmosphere |
-3 layers of cloudes formed of hydrogen-rich molecules -cloud layers are located at certain temperatures w/in the atmosphere -cloud strips parallel to equator are: ---1-light-colored, high-pressure regions of rising gas ---2-darker belts, lower-pressure areas of shrinking gas -spots in Jupiter's atmosphere, including the Great Red Spot, are circulating weather patterns
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Jupiter's Moons |
Galilean moons -linked together in orbital resonance -Lo: active volcanoes, orbits Jupiter 4 times -Europa: smooth ice and cracks, orbits 2 times -Ganymede: grooved terrain, orbits once |
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Jupiter's Ring |
: composed of small particles that are bright when illuminated from behind (forward scattering)
-Lies within the Roche Limit
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Jupiter's Roche Limit |
: the distance from a planet within the tidal stress can destroy or prevent one from forming
*Jupiter's ring lies within the Roche Limit |
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Saturn |
-less dense than water -contains a small core w/ less metallic hydrogen than Jupiter, therefore its magnetic field is 20 times weaker -Saturn's moons are icy and heavily cratered -Rings: composed of icy particles ranging in size from boulders to dust -Shephard satellites |
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Saturn's Moons |
Titan: -Saturn's largest moon -cold, cloudy nitrogen atmosphere -so cold that gas molecules do not travel fast enough to escape Enceladus: -has a light surface with some uncratered regions |
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Saturn's Rings |
: composed of icy particles ranging in size from boulders to dust -composition and brightness of the rings' particles vary *grooves in the rings can be produced by orbital resonances, or waves, that propagate through the rings, caused by the moons near or within the rings |
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Saturn's Shephard Satellites |
: the gravitational effect of small moons; can cause narrow rings and sharp edges -Jovian planets' rings cant be material left over from the formation of the planet; rings are replenished occasionally with material produced by meteoroids, asteroids, and comets colliding with moons |
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Uranus |
-1/3 the diameter of Jupiter, 1/20 as massive -internal pressure cant produce liquid hydrogen -heavy-element core, mantle of solid slushy ice and rocky material below a hydrogen-rich atmosphere -atmosphere is almost featureless at visible wavelengths (*pale blue color is caused by traces of methane, which absorbs red light) -rotates on it's side -Uranus' larger moons are icy and heavily cratered -Oviods -Occultations -Rings |
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Uranus: Ovoids |
: grooves on Miranda (the innermost moon) cause by internal heat driving convection in the icy mantle |
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Uranus: Occultations |
: the passage of the planet in front of a star during which the rings momentarily blocked the star's light
***How the rings of Uranus were discovered |
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Uranus: Rings |
-narrow hoops of ice with traces of methane confined by shepherd satellites |