Exam 2 Study Guide
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EAPS 105, The Planets
Exam 2 Study Guide
Know the following:
Unit 4: Heating and Cooling
1. The consequences of suddenly stopping a moving object.
when a moving object hits something and is suddenly stopped, it deforms causing its atoms vibrate more, and thus its temperature rises.
2. The state of the interiors of new terrestrial planets.
melted interior
3. The meaning of primordial heating.
accretion and core formation are known as primordial heating, since they can only occur during planet formation
4. What Lord Kelvin neglected in his calculation of the age of the Earth.
radioactive decay
(how long it took for earth to cool from a very hot melted interior to the cooler temperature inferred by observed heat flow today)
5. Why radioactive decay produces heat.
unstable (too many of too few neutrons results in a force imbalance and radioactive decay) elements decay into more stable
(held together by strong force) atoms, emitted particles cause collisions that produce heat
6. Why the interior of the Earth is hot today.
half from ongoing radioactive decay and half from leftover heat from accretion and core formation (primordial heating)
7. Why tidal heating is so intense on Io, but not the Moon.
lo has an elliptical orbit around Jupiter causing it to be continuously deformed( like an accordion), generating heat (tidal heating is sufficient to melt lo's mantle, making it the most volcanically active body in solar system)
(moon has nearly circular orbit, so the shape of moon does not change even though moon
is elongated by tidal forces. Thus, it doesn’t experience much continuous deformation nor
tidal heating)
8. The additional source of internal heating of the interiors of the giant planets.
compression :the immense gravities of giant planets cause their interiors to compress, another way to deform that causes heating
9. The only means by which a body can shed its heat to space.
radiative heat
( only takes place at surface) (heat is transferred though electromagnetic waves through a transparent medium)
10. Why smaller planets cool faster than larger ones.
- less primordial heat( less impacts, smaller core)
- less radioactive elements keep them hot
- smaller body have larger surface areas to volume ratios, more efficient to get rid of heat
11. How heat is transferred with conduction.
through a solid by the spread of vibrations to surrounding regions
(slowest process of heat transfer, even small bodies can stay warm deep in their interior for very long time)
12. How heat is transferred with convection.
through the upward motion of hot and this buoyant(low density) fluids, which then cool and descend causing convection cells
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13. How convection can occur within a solid.
under some conditions, some solids can also flow, called solid state convection
14. How heat transfer occurs within the Earth’s mantle.
mantle(solid): convection
(lithosphere(solid): conduction, outermore(liquid): convection, inner core(solid): conduction)
15. What a lithosphere is.
the cold strong outer shell of the Earth consisting of the crust and uppermost mantle
16. What asthenosphere is.
the hot and very weak layer that underlies lithosphere. it flows as a viscous flow
17. What drives plate tectonics.
driven by mantle convection
(plate tectonics is the process where strong lithosphere move around over a weak asthenosphere) (Earth is the only planet in solar system to utilize plate tectonics to shed internal heat)
18. What a mid-ocean ridge is.
magma from below reaches the surface and cools to form new ocean crust and lithospheric mantle that then moves outwards from the ridge; spreading center where new
ocean crust forms then spread out
(heat flow is highest at mid-ocean ridges)
19. What is subduction zone is.
where oceanic plates dive(subduct) back into the Earth's interior
20. What a transform fault is.
plates slide past each other on the surface
21. Whether there are transform faults on Jupiter’s moons Europa and Ganymede.
Yes. (does not have plate tectonics, its icy surface continuously broken up and pushed around by Jupiter’s tidal force, causing many transform boundaries/ faults)
22. A planet cannot experience plate tectonics without mid-ocean ridges or subduction zones.
Yes. If a planet's lithosphere is too strong to break, resulting to a single plate planet without midocean ridges or subduction zones.
23. That a planet can experience mantle convection without plate tectonics.
Yes, and it is referred to as stagnant lid convection
24. That only Earth exhibits plate tectonics.
Yes, Earth is the only terrestrial planet in the solar system with plate tectonics
25. The cause of young thrust faults on the surface of Mercury and The Moon.
As a single plate planet cools over time, surface contract as its interior continues to cool, causing thrust fault.
26. The cause of young thrust faults on the surface of Pluto.
normal faults due to global expansion caused by cooling subsurface ocean
(water expands when it freezes, causing Pluto’s surface to expand as its subsurface ocean freeze)
27. The plausible explanations of why Venus does not experience plate tectonics like Earth.
1. Venus is so hot that its lithosphere may slowly flow rather than break into plates.
2. Venus is so dry that its lithosphere may be too strong to break
28. How a permanent magnet is created.
Ferromagnetic materials (like iron) can hold onto their induced magnetic fields even after
nearby magnet is removed
( tiny magnetic fields can be aligned by placing the object near a strong magnet, creating a net magnetic field)
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29. How an induced magnet field is created.
Moving electrons( electron current) produces a magnetic field perpendicular to the direction of the current (magnetic field only exists when the electric current is present)
30. How a magnetic field induced by running a current through a wire can be made stronger.
increasing the current, coiling the wire, coiling wire around a ferromagnetic material
31. The components used to generate Earth’s magnetic field.
liquid iron outer core provides all the elements necessary to generate very strong induced magnetic field
- The electrical current comes from motion of the electrical conducting liquid iron as the outer core convects.
- The spin of the Earth causes the liquid iron to convect in spirals like coils in a wire.
- Those coils spiral around a core of liquid iron, thus greatly increasing the strength of the
magnetic field.
32. The consequence of Earth’s magnetic north pole actually being a magnetic south pole.
Earth's magnetic north pole was designated a north pole based on geography and not magnetism, so the earth's magnetic north pole is actually located near earth's geographic south pole
33. What protects us from the solar wind.
Earth's magnetic field and atmosphere. most of the charge particles are deflected by the magnetic field, rest are absorbed by our atmosphere
34. What causes auroras (northern and southern lights).
the deflection of the solar wand by magnetic field directs charged particles to our poles where it excites the nitrogen and oxygen on our atmosphere
35. What a magnetosphere is.
the region where a planet’s magnetic field is the predominant magnetic field 36. Why the Sun has such a strong magnetic field.
made of plasma, a gas like state of matter where electrons and ions have separated, creating a super hot mix of charged particles that create electric currents and the strongest
magnetic field.
37. What it means that the Voyager 1 and 2 spacecraft have left the Sun’s heliosphere(sun's magnetosphere).
they can no longer use a compass to find their way home
38. Why Venus does not have a magnetic field.
due to its slow spin (same reason for mercury)
39. The layer within Jupiter responsible for its magnetic field.
metallic hydrogen
(tremendous pressure within Jupiter compress hydrogen into a metallic state, a liquid that has free flowing electrons)
40. The layer within Neptune responsible for its magnetic field.
water and ammonia in the ice giant mantle interact to create charged ions which are electrically conducting
Unit 5: Volcanism
41. The difference between magma and lava. Maximum & Deductible Coverage
magma is melted rock beneath the surface, and it's called lava when flows out
42. Know that tectonic plates do not sit on an ocean of magma.
tectonic plates do not float on an ocean of molten rocks.
43. The ways to get hot, but still solid, rocks to melt.
1. increase temperature (not a common way to induce volcanism)
2. decrease pressure
( called depressurized melting)(reduce the melting temperature)
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3. add water to the mineralogy
(called hydration-induced melting)(reduce the melting temperature by breaking up ling silica chains)
44. The type of volcanism observed to occur on the other terrestrial planets.
hot spots
(mid ocean ridges and subduction zone requires plate tectonics)
45. The process that causes hot rocks to melt at subduction zones.
water pushed out from the subducting plate lowers the melting temperature of hot mantle above, causing it to melt
(hydration induced melting)
46. What the Ring of Fire refers to.
subduction zone volcanism occurs everywhere plates are subducted, causing a ring of fire
around the pacific ocean
47. Why there are fewer active volcanoes in the southwestern US.
because there is no active subduction zone in the southwestern US
48. What process that causes hot rocks to melt at hotspots.
depressurized melting (when the hot spot plume head reaches the base of the lithosphere, it begins to melt by depressurized melting, causing massive volcanism)
49. Why hotspots on Earth lead to a line of volcanoes.
when a tectonic plate moves over a hot spot, volcanoes initiate over the hot spot then go extinct as the volcano moves away from it, and a new volcano develops.
50. What viscosity is a measure of.
how easily a fluid flows
51. The kind of volcano low viscosity lava leads to.
broad, shallow sloped volcano, aka shield volcanoes
(high viscosity lead to narrow, highly sloped volcanoes, aka composite volcanoes)
52. The kind of volcano that has alternating layers of lava and pyroclastic flows
(debris from explosive eruptions)
.
stratovolcanoes (form due to has alternating layers of lava and pyroclastic flows and high viscosity effusive lava flows)
53. The kind of volcano that forms when tephra (air cooled lava fragments) is thrown out of a volcanic vent.
cinder cone volcanoes
(very high viscosity) 54. What an effusive volcanic eruption is
.(determine by the amount of pressure that can build beneath a volcano)
if magna can flow to the surface through a vent or crack without building up high pressure
(explosive if rising magma gets trapped and pressure beneath the surface builds)
55. Why pressure in magma builds up as it rises toward the surface.
As magma moves up to the surface the pressure on it from overlying rocks decreases causing
the dissolved gas (e.g. sio2) to expand to form gas bubble> gas bubble take up a lot more volume than dissolved gas, causing pressure to build within the magma
56. What volcanic ash is.
ash are the shards of the volcanic bubbles- broken gas
57. The combination of magma viscosity and gas content that leads to effusive eruptions.
low content of sio2, lower viscosity, and lower gas content, hotter eruption 58. The most powerful type of explosive eruption.
Plinian eruptions (Hawaiian> Strombolian> Vulcanian> Pilinian)
59. What giant flood basalts are.
huge floes of over 1000 km3 that occur over a relatively short amount of time. (on earth can cause climate change and mass extinction)
60. Where giant flood basalts originate from.
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when hot spot mantle plumes first protrude to the surface 61. That all other terrestrial planets besides Earth are covered by flood basalts.
Yes (Venus and Mercury does bot have tectonics) (if a planet lacks plate tectonics, its internal heat is shed via flood volcanism)
62. That no volcanoes are found on Mercury.
true, the viscosity of mercury's lava is too low to develop volcanic topography
(instead, the lava seeps out of fissures and fill up impact craters creating ghost craters)
63. Why all of Venus’ volcanoes are relatively flat compared to those on Earth.
Venus has a much denser atmosphere
64. How we know that Venus was completely resurfaced by volcanism ~500 million years ago.
The uniform distribution of impact craters on Venus
65. Why Olympus Mons on Mars is such a big hot spot volcano.
1. gravity on mars is 1/3 that of earth
2. mars does not have plate tectonics( to move a volcano off a hot spot)
3. mars does not have significant erosion process
66. Why large impact basins on the Moon are filled with mare(flood basalts on moon).
because they have the lowest topography
(the moon did not retain sufficient heat to generate enough volcanism to cover the entire surface, only on the near-side)
67. How a caldera forms.
a caldera is a large circle depression formed when the surface collapses into an emptying magma chamber
68. The components of an eruption column.
1. momentum-driven ascent region: rising ash overshoots the neutral buoyancy level
2. umbrella region/ neutral density level: the density of the ash equals that of air, so it stops rising and spreads out
3. convective ascent region: the buoyancy of hot, low density ash allows it to continue to rise on convection currents
4. gas thrust region: ash is powered upwards by high pressure from expanding gases
69. What cryovolcanism is.
cryovolcanism is the eruption of water or ices, such as nitrogen, ammonia, or methane, instead of molten rock
(observed on icy bodies and thought to erupt from a subsurface ocean due to tidal heating
through cracks in the ice that open and close due to these same tidal forces.)
70. That Earth does not have any cryovolcanoes.
There are no readily identifiable cryovolcanoes on earth
71. That cryovolcanism on Enceladus ejects ice into Saturn’s E ring.
Saturn's E-ring results from water ice ejected from Enceladus' cryovolcanic eruptions at escape velocities
Unit 6: Impact Cratering 03
72. The effect of increasing the distance from a planet on its escape velocity.
the greater the distance from a planet center, the lower the velocity needed to escape its gravity
( the grater the mass, the higher the velocity needed)
73. What the minimum impact velocity of an asteroid depends on.
the minimum impact velocity is the escape velocity of the body being impacted (because even a stationary object will be accelerated into the body by the force of its gravity)
74. Why most asteroids hit the Earth and Moon with similar velocities.
objects hitting the moon get an assist from Earth's gravity
75. Why comets hit the Earth and Moon faster than asteroids.
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Comets spend more time being accelerated toward the inner solar system by the sun's gravity (comets come from farther out in the solar system)
76. Why the impact velocity of asteroids into Mercury is faster than the other terrestrial planets.
because of its close proximity to the sun, which gives it a big gravitational assist
77. How the size of impact craters compares to the size of their impactor.
impact craters are generally 10-30 times larger than the impactor (because impacts act as explosions)
78. Why most craters on the Moon are round.
because impacts act as explosions, impact craters are mostly round, even though most impacts occur at oblique angle 79. The order of processes that occurs during an impact.
1. contact and compression: very initial stage where the impactor hits the planet surface and begins to compress the surface downwards.
2. excavation step: crustal rocks are excavated and thrown out of the developing crater (transient crater is the maximum crater size that occurs at the end of the excavation stage.
The rocks are not strong enough to support the steep topography of this crater, so it begins to collapse)
3. modification stage: the transient crater collapses filling the crater with broken rock
(breccia) and melted rock
(impact melt)
80. What a transient crater is.
transient crater is the maximum crater size that occurs at the end of the excavation stage. (The rocks are not strong enough to support the steep topography of this crater, so it begins to collapse)
81. Characteristics of simple craters. (smallest)
circular bowl shaped depression/ crater floor is underlain by a lens of broken rock (breccia)/ distinct rim stands above surrounding planes
( the shape of impact craters is dependent of their size, bigger or faster impactor>increase
crater size)
82. Characteristics of complex craters.(middle)
the central peak of a complex crater is caused by the rebound of the crust beneath the transient crater/ the floor of the crater is flat, not bowl shaped/ the rim is terraced because rim rocks are not strong enough to support the steep walls
( their larger size causes more collapse during the modification stage)
83. Characteristics of multi-ring basins. (largest)
As craters get bigger, they transition into peak-ring basins and then multi-ring basins
84. How far an ejecta blanket usually extends beyond a crater rim.
the surrounding region is blanketed with ejecta (called the ejecta blanket) for about one crater diameter
85. Why ejecta blankets on Mars look fluidy.
Mars has a thick permafrost layer
( subsurface ice)
86. How the shape of an impact craters and ejecta blankets are influenced by the angle of impact.
lower angled impacts lead to non-uniform ejecta blankets, but still round craters
87. What crater rays are.
bright lines of ejecta that extend far from the impact site (young craters on the moon appear brighter and exhibit crater rays due to the excavation of brighter material from beneath the surface)
88. What space weathering is.
damage by micrometeorites and the solar wind
89. Why young craters appear brighter than older craters on the Moon.
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young craters on the moon appear brighter and exhibit crater rays due to the excavation of brighter material from beneath the surface
90. What it means that the Moon is completely saturated with impact craters.
meaning that new craters cover/ destroy older ones s.t. the number of identifiable craters does not change with time
91. Why there are fewer recognized impact craters on the Earth compared to the Moon.
The moon has no significant erosional processes.
92. Characteristics of the two Clearwater Lakes found in Quebec, Canada.
1. Clearwater Lakes occupy two eroded impact craters that are 36 and 26 km diameter.
2. originally thought to be the product of a double impact, radiometric dating suggests different ages
93. Why the Kentland Crater in Indiana does not look like an impact crater.
because the top 300 m of the crater was removed by glaciation
- glacial erosion exposed rock deep within the central peak, bringing crushed limestone( valuable for roads and farming) to the surface
- the only place in Indiana where sedimentary rock layers do not lie horizontally, as the formation of the crater central peak caused these layers to rotate to near vertical
94. Why shatters cones are evidence of an asteroid impact.
shatter cones are cone shaped rocks that result from the way shock waves shatter rock as they travel through it ( any time the shock wave encounters an inconsistency in the rock, a new cone is generated)
95. The percent of species on Earth that died off in the Cretaceous-Paleogene extinction event.
~75% (occurred 66 million years ago)
96. The evidence that a large impact killed off the dinosaurs.
- the thin layer that separates the Cretaceous
(dinosaurs) from Paleogene
(mammals) sediments contains a lot of iridium, shocked quartz, and soot, indicative of a giant impact and global fire.
- parts of a paddlefish skull with impact spherules
(balls of melted rock common to large impact sites) in its gill
97. How the Chicxulub Crater was found.
( the crater associated with the impact that killed off dinosaur)
By measuring variations in gravity
98. How often a 10-km-diameter asteroid hits the Earth.
every 100,000,000 years
99. How many Near Earth Asteroids ≥ 1 km in diameter are being tracked.
most of them(~1000)
100. Know that there are no significant asteroids on a collision course with Earth.
there are no tracked near-Earth asteroids of significant size(>10 m) with a significant chance(>1/300) of hitting the Earth in the next several hundred years.
101. The best strategy to avoid an extinction level size asteroid from hitting the Earth.
deflect it ( focus solar heat, spacecraft propulsion, solar soil)
102. The objective of the Double Asteroid Redirection Test.
crash a spacecraft into a small asteroid Dimorphous to see how much it altered its orbit around the larger asteroid Didymos
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