Astronomy CH 9
How large is an impact crater compared to the size of the impactor?
10 times larger
How long, approximately, do geologists estimate it takes for the entire seafloor to be replaced due to plate tectonics?
200 million years
Which internal energy source produces heat by converting gravitational potential energy into thermal energy?
Accretion and Differentitaiton/ both A and B
The core, mantle, and crust of a planet are defined by differences in their?
Composition
The three principal sources of internal heat of terrestrial planets are?
accretion, differentiation, and radioactivity
Heat escapes from a planet's surface into space by thermal radiation. Planets radiate almost entirely in the wavelength range of the?
Infared
What is the most important factor that determines the thickness, and therefore strength, of the lithosphere?
Internal Temperature
Why does Earth have the strongest magnetic field among the terrestrial worlds?
It is the only one that has both a partially molten metallic core and reasonably rapid rotation
Which of the following best describes convection?
It is the process in which warm material expands and rises while cool material contracts and falls.
How did the lunar maria form?
Large impacts fractured the Moon's lithosphere, allowing lava to fill the impact basins.
Which of the following show evidence of ancient river beds?
Mars
Rank the five terrestrial worlds in order of size from smallest to largest?
Moon, Mercury, Mars, Venus, Earth
Some of the oldest continental crust on Earth lies in?
Northeastern Canada
How does seafloor crust differ from continental crust?
Seafloor crust is thinner, younger, and higher in density.
Under what circumstances can differentiation occur in a planet?
The planet must have a molten interior
Which of the following best describes why the smaller terrestrial worlds have cooler interiors than the larger ones?
They have relatively more surface area compared to their volumes.
What kind of surface features may result from tectonics?
Valleys, mountains, volcanos, and cliffs/ all of the above
What are the conditions necessary for a terrestrial planet to have a strong magnetic field?
both a molten metallic core and reasonably fast rotation
How have we been able to construct detailed maps of surface features on Venus?
by using radar from spacecraft that were sent to orbit Venus
Which two properties are most important in determining the surface temperature of a planet?
distance from the Sun and atmosphere
Which of the following is not evidence for plate tectonics on Earth?
existence of volcanoes
The Caloris Basin on Mercury covers a large region of the planet, but few smaller craters have formed on top of it. From this we conclude that?
formed toward the end of the solar system's period of heavy bombardment
Shallow-sloped shield volcanoes are made from lava that?
has a medium viscosity
Ridges in the middle of the ocean are places where?
hot mantle material rises upward and spreads sideways, pushing the plates apart
What process has shaped Earth's surface more than any other?
plate tectonics
The geysers and hot springs of Yellowstone National Park result from?
plumes of hot mantle rising in a hot spot within a plate.
Olympus Mons is a?
shield volcano on Mars
What type of stresses broke Earth's lithosphere into plates?
the circulation of convection cells in the mantle, which dragged against the lithosphere
Which of the following describes impact cratering?
the excavation of bowl-shaped depressions by asteroids or comets striking a planet's surface
Which of the following does not provide evidence that Mars once had flowing water?
the presence of vast canals discovered in the late 1800s by Giovanni Schiaparelli and mapped by Percival Lowell
When we see a region of a planet that is not as heavily cratered as other regions, we conclude that?
the surface in the region is younger than the surface in more heavily cratered regions.
Which of the following describes erosion?
the wearing down or building up of geological features by wind, water, ice, and other phenomena of planetary weather