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Astronomy9-13,24 (Els) > Chapter 9 > Flashcards

Chapter 9 Flashcards

1
Q

Volcanism

A

The eruption of molten rock, or lava, from a planet’s interior onto its surface

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2
Q

Differentiation

A

The process by which gravity separates materials according to density, with high-density materials sinking and low-density materials rising

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3
Q

Electromagnetic field

A

An abstract concept used to describe how a charged particle would affect other charged particles at a distance

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4
Q

subduction zones

A

Places where one plate slides under another.

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5
Q

mid-ocean ridges

A

Long ridges of undersea volcanoes on Earth, along which mantle material erupts onto the ocean floor and pushes apart the existing seafloor on either side. These ridges are essentially the source of new seafloor crust, which then makes its way along the ocean bottom for millions of years before returning to the mantle at a subduction zone.

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6
Q

stratovolcano

A

A steep-sided volcano made from viscous lavas that can’t flow very far before solidifying.

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7
Q

core (of a star)

A

The central region of a star, in which nuclear fusion can occur.

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8
Q

erosion

A

The wearing down or building up of geological features by wind, water, ice, and other phenomena of planetary weather.

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9
Q

impact

A

The collision of a small body (such as an asteroid or comet) with a larger object (such as a planet or moon).

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10
Q

geology

A

The study of surface features (on a moon, planet, or asteroid) and the processes that create them.

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11
Q

eruption

A

The process of releasing hot lava on a planet’s surface.

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12
Q

basalt

A

A type of dark, high-density volcanic rock that is rich in iron and magnesium-based silicate minerals; it forms a runny (easy flowing) lava when molten.

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13
Q

spreading centers (geological)

A

Places where hot mantle material rises upward between plates and then spreads sideways, creating new seafloor crust.

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14
Q

fault (geological)

A

A place where rocks slip sideways relative to one another.

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15
Q

impact cratering

A

The excavation of bowl-shaped depressions (impact craters) by asteroids or comets striking a planet’s surface.

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16
Q

seafloor spreading

A

On Earth, the creation of new seafloor crust at mid-ocean ridges.

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17
Q

lunar maria

A

The regions of the Moon that look smooth from Earth and actually are impact basins.

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18
Q

tectonics

A

The disruption of a planet’s surface by internal stresses.

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19
Q

seismic waves

A

Earthquake-induced vibrations that propagate through a planet.

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20
Q

mantle (of a planet)

A

The rocky layer that lies between a planet’s core and crust.

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21
Q

geological activity

A

Processes that change a planet’s surface long after formation, such as volcanism, tectonics, and erosion.

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22
Q

Martian meteorites

A

Meteorites found on Earth that are thought to have originated on Mars.

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23
Q

continental crust

A

The thicker lower-density crust that makes up Earth’s continents. It is made when remelting of seafloor crust allows lower-density rock to separate and erupt to the surface. Continental crust ranges in age from very young to as old as about 4 billion years (or more).

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24
Q

volcanic plains

A

Vast, relatively smooth areas created by the eruption of very runny lava.

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25
plates (on a planet)
Pieces of a lithosphere that apparently float upon the denser mantle below.
26
impactor
The object responsible for an impact.
27
plate tectonics
The geological process in which plates are moved around by stresses in a planet's mantle.
28
conduction (of energy)
The process by which thermal energy is transferred by direct contact from warm material to cooler material.
29
subduction (of tectonic plates)
The process in which one plate slides under another.
30
convection cell
An individual small region of convecting material.
31
seafloor crust
On Earth, the thin, dense crust of basalt created by seafloor spreading.
32
magnetic field
The region surrounding a magnet in which it can affect other magnets or charged particles.
33
radioactive decay
The spontaneous change of an atom into a different element, in which its nucleus breaks apart or a proton turns into an electron. It releases heat in a planet's interior.
34
shield volcano
A shallow-sloped volcano made from the flow of low-viscosity basaltic lava.
35
outgassing
The process of releasing gases from a planetary interior, usually through volcanic eruptions.
36
core (of a planet)
The dense central region of a planet that has undergone differentiation.
37
geological processes
The four basic geological processes are impact cratering, volcanism, tectonics, and erosion.
38
viscosity
The thickness of a liquid described in terms of how rapidly it flows; low-viscosity liquids flow quickly (e.g., water), while high-viscosity liquids flow slowly (e.g., molasses).
39
magma
Underground molten rock.
40
hot spot (geological)
A place within a plate of the lithosphere where a localized plume of hot mantle material rises.
41
impact basin
A very large impact crater, often filled by a lava flow.
42
crust (of a planet)
The low-density surface layer of a planet that has undergone differentiation.
43
lithosphere
The relatively rigid outer layer of a planet; generally encompasses the crust and the uppermost portion of the mantle.
44
convection
The energy transport process in which warm material expands and rises while cooler material contracts and falls.
45
radar mapping
Imaging of a planet by bouncing radar waves off its surface, especially important for Venus and Titan, where thick clouds mask the surface.
46
planetary geology
The extension of the study of Earth's surface and interior to apply to other solid bodies in the solar system, such as terrestrial planets and jovian planet moons.
47
sedimentary rock
A rock that formed from sediments created and deposited by erosional processes.
48
impact crater
A bowl-shaped depression left by the impact of an object that strikes a planetary surface (as opposed to burning up in the atmosphere).
49
surface area-to-volume ratio
The ratio defined by an object's surface area divided by its volume; this ratio is larger for smaller objects (and vice versa).
50
Mercury and the Moon show scars of their battering during the \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_.
Heavy bombardment
51
The terrestrial planets, along with the Moon, likely looked quite similar when they were young. What has caused them to change in different ways such that they no longer look similar?
The fundamental properties of the planets.
52
The three layers of a planet divided by density are \_\_\_\_, \_\_\_\_\_\_, \_\_\_\_\_\_
core, mantle, crust
53
Why are larger worlds spherical and small ones more potato-shaped?
Rock can deform and flow. The weak gravity of small objects is not able to over come the rigidity of its rocky material, so the object retains its potato-like shape. For larger worlds though, gravity can overcome the strength of solid rock, slowly deforming and molding it into a spherical shape.
54
What are three sources of energy from within a planet?
Heat of accretion (Accretion deposits energy brought in from afar by colliding planetesimals. The planetesimal approaches a forming planet, its gravitational potential energy is converted to kinetic and upon impact is converted to thermal) Heat from differentiation (the sinking of dense material and rising of less dense means mass moving inward losing gravitational potential energy which is converted to thermal energy by friction) Heat from radioactive decay (the rock and metal building the world contained radioactive isotopes. When those nuclei decay, subatomic particles fly off at high speeds, colliding with neighboring atoms and heating them)
55
What are the three ways interiors cool off?
Convection (hot material expands and rises while cool contracts and falls. Therefore heat is transferred toward the surface) Conduction (the transfer of heat from hot material to cooler material through contact. Occurs through microscopic collisions of individual atoms or molecules) Radiation (planets lose heat to space through radiation. Objects emit thermal radiation characteristic of their temperatures. This carries energy away, and thus cools it)
56
What is the single most important factor in planetary cooling?
The size of the planet
57
Suppose we use a baseball to represent Earth. On this scale, the other terrestrial worlds (Mercury, Venus, the Moon, and Mars) would range in size approximately from that of \_\_\_\_\_\_.
a golf ball to a baseball
58
Which of the following is an example of convection?
Warm air expanding and rising while cooler air contracts and fall.
59
What are the basic requirements for a terrestrial world to have a global magnetic field?
A core layer of molten, convecting material and sufficiently rapid rotation.
60
The processes responsible for virtually all surface geology are \_\_\_\_\_\_\_\_\_.
impact cratering, volcanisms, tectonics, and erosion
61
Which of the following best describes the lunar maria?
Relatively smooth, flat plains on the Moon
62
What observational evidence supports the idea that Mercury once shrank by some 20 kilometers in radius?
The presence of many long, tall cliffs
63
Olympus Mons is \_\_\_\_\_\_.
a huge shield volcano on Mars
64
On average, how fast do the plates move on the Earth?
A few centimeters per year
65
How does seafloor crust differ from continental crust?
Seafloor crust is thinner, younger, and higher in density.
66
The cores of the terrestrial worlds are made mostly of metal because \_\_\_\_\_\_.
metals sunk to the centers a long time ago when the interiors were molten throughout
67
Suppose we had a device that allowed us to see Earth's interior. If we looked at a typical region of the mantle, what would we see happening?
not much - on human time scales, the mantle looks like solid rock
68
Recent evidence suggests that Mars once had a global magnetic field. Assuming this is true, how could one explain why Mars today lacks a global magnetic field like that of Earth?
Mars's interior has cooled so much that its molten core layer no longer undergoes convection.
69
What most likely explains why Venus does not have a global magnetic field like Earth?
Its rotation is too slow.
70
Most of the Moon's surface is densely covered with craters, but we find relatively few craters within the lunar maria. What can we conclude?
The maria formed after the heavy bombardment ended.
71
What are the two geological features that appear to set Earth apart from all the other terrestrial worlds?
plate tectonics and widespread erosion
72
Why are there fewer large impact craters on the Earth's seafloor than on the continents?
Seafloor crust is younger than continental crust, so it has had less time in which to suffer impacts.
73
Why is Earth's continental crust lower in density than seafloor crust?
Continental crust is made as the lowest-density seafloor crust melts and erupts to the surface near subduction zones.
74
Which two factors are most important to the existence of plate tectonics on Earth?
mantle convection and a thin lithosphere
75
What's the fundamental reason that Mars, unlike the Earth, has become virtually geologically dead?
its small size compared to Earth
76
Size: twice as big as Earth. Distance from Sun: same as Mercury. Rotation rate: once every 6 months.
77
Size: same as the Moon. Distance from Sun: same as Mars. Rotation rate: once every 10 days.
78
Size: same as Venus. Distance from Sun: same as Mars. Rotation rate: once every 25 hours.
79
What are the four main geological processes that shape planetary surfaces?
Impact cratering (bowl-shaped impact craters by asteroids or comets striking a planet's surface Volcanism (the eruption of molten rock, or lava, from a planet's interior onto its surface) Tectonics (the disruption of a planet's surface by internal stresses) Erosion (the wearing down or building up of geolocgical features by wind, ice, and other phenomena of planetary weather)
80
Craters are typically ____ times larger than the object that created them.
10
81

Astronomy9-13,24 (Els) (6 decks)

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