Questions and Answers of Planetary Geoscience

What are the first-order changes in geologic processes that characterized the Noachian, Hesperian, and Amazonian Periods?
Give two examples of how the analysis of martian meteorites has improved our understanding of the unseen interior of Mars.
How has the Curiosity rover’s exploration complemented orbital remote sensing of Gale crater?
How has the exploration of the surface of Meridiani Planum by the Opportunity rover augmented the interpretation of hematite detected from orbit?
How has the interpretation of Gusev crater as an ancient lakebed from orbital data been changed by the Spirit rover’s exploration of the crater floor?
Draw and label a cross-section of the Earth’s interior, noting each major compositional boundary and phase change.
Briefly describe the systemic challenges faced by the engineers who design interplanetary spacecraft and the scientists who design the instruments they carry.
What are uncompressed mean densities, and what can they tell us about planets?
What characteristics do the terrestrial planets share?
What characteristics do the giant planets share?
How do we subdivide/classify the small bodies of the Solar System?
Why do you suppose our eyes evolved to be sensitive to visible wavelengths of light?
What is the difference between a radiance spectrum, an emissivity spectrum and a reflectance spectrum?
What is meant by the term “hyperspectral cube?”
How does n-dimensional cluster analysis work in hyperspectral mapping?
How can combining analyses of different remote sensing instruments (with different spectral ranges, spatial resolutions, and other characteristics) provide a more complete picture of the geology of a
What are the mechanisms by which gamma rays are produced in planetary surfaces?
Why are the energies of neutrons that leak from planetary surfaces so strongly dependent on the amount of hydrogen in the surface?
How are stratigraphic principles modified for use in planetary geologic mapping and development of planetary stratigraphic timescales?
How are crater populations quantified, and how can crater plots be used to tell relative time?
What is an equilibrium population of craters, and why is recognizing it important?
Distinguish between geochronologies based on long-lived and extinct radioisotopes.
For the lower (front) half of Figure 3.10, define two map units. State their characteristics and the characteristics of their contact. Draw a contact on the image between the two units (e.g., use
In Figure 3.11b, identify and state the observations for why the unit DR5 is almost younger than every other unit around it and why the Subdued Plains are older than every other unit around it.Figure
What would be the most difficult step for you to undertake if you had the opportunity to use Figure 3.11a to create a geologic map? Why? Discuss with your classmates.Figure 3.11a (a)
Which geophysical techniques might have been used to construct Figure 3.12 (for both Earth and Mercury)?Figure 3.12 Earth Upper mantle Lower
Why does the Sun shine?
How do stars evolve on the H-R diagram, what nucleosynthesis processes occur at different stages, and how do elements get recycled?
What do we mean by Solar System element abundances, and how are they determined?
What are chondrites, and why are they important?
What is the condensation sequence?
How do the geochemical and cosmochemical behaviors of elements differ?
What is an accretion disk, and how does it evolve into a planetary system?
What do observations of young stars and numerical simulations of accretion reveal about planet formation?
Why do we use refractory inclusions to date the age of the Solar System, and what is its age?
How are short-lived and long-lived radionuclides used in combination to determine the timing of early solar system processes?
What evidence suggests that the Solar System has experienced a dynamic orbital evolution?
Why does radioactive decay release heat, and which long-lived radioisotopes are responsible for planetary heating?
Which heating mechanisms were responsible for the differentiation of the Earth? Which heating mechanisms are important now?
What evidence suggests that the Moon’s differentiation involved a magma ocean?
What controls the separation from the mantle of core materials and of magmas that become the crust?
How is differentiation in the giant planets different from the terrestrial planets?
Explain how seismic velocities provide information on the Earth’s interior structure.
Mercury’s mean density is 5.43 g/cm3. If Mercury consists entirely of rock (average density = 3.3 g/cm3) and iron metal (density = 7.9 g/cm3), calculate the planet’s fractional abundance of iron
Explain how we can use the sizes, masses, and shapes of planets to model their interiors.
Imagine a sedimentary basin on some planetary body that is confined on all sides and filled to a depth of 1 km. The horizontal strains, εxx and εyy are both zero, and the vertical stress at any
How does the high-pressure phase diagram for hydrogen help explain the interior structure of Jupiter?
Describe how to estimate the thickness of the lithosphere from topography near a big surface load. Use this technique to compute the elastic thickness (h) of the lithosphere on Europa from the data
What does it mean to say that something is a linear elastic material? How are stress and strain related for a linear elastic material? How does strain in one dimension affect strain in another
The South Pole-Aitken (SPA) impact basin, located on the far side of the Moon, is about 8 km deep and appears to be in isostatic balance. Describe how you would use the principle of isostasy to
How can topography and gravity measurements be combined to determine the compensation state of surface features?
Describe diurnal temperature variations at the surface and near-surface (top few meters) of planetary bodies.
Why are some craters on Ganymede, Enceladus, and other icy bodies not topographic lows? Why do they still have raised rims?
What does it mean to say that something is a Newtonian fluid? What are the various factors that affect the effective viscosity of geologic materials? Which of these factors imposes the largest
Considering terrestrial planets and satellites with radii greater than 200 km, are surfaces with stagnant-lid or active-lid tectonics more abundant? Why do you believe that one behavior has been more
Why is it reasonable to say: “From a material perspective, an icy lithosphere is more likely to show evidence for active-lid tectonics than a rocky lithosphere.”
Contrast the roles of thermal and tidal sources as driving stresses for triggering active-lid tectonics.
What are the similarities and differences between stagnant-lid surfaces for icy satellites and rocky planets?
Why is Europa interpreted to be a very tectonically active icy satellite, whereas Enceladus is a selectively active satellite?
Develop two lists:(a) Evidence favoring Venus having always been a stagnant-lid body; and(b) Evidence favoring Venus having one or more episodes of active-lid behavior in its past and/or future.
How and why do melting mechanisms, relative volumes of magmas, and magma compositions relate to plate tectonic settings on Earth?
Describe the kinds of volcanic landforms that occur on the terrestrial planets.
What kinds of eruptions are missing on Venus, and why?
Why are basalts so ubiquitous, and how does basalt chemistry vary among the planets?
How has planetary volcanism changed over time on the Earth and terrestrial planets?
What are the morphological differences between simple and complex craters? How do these morphologies scale with crater size and target planet gravity?
What are the three stages of crater formation, and what processes characterize each stage?
What portions of the target are ejected, melted, or otherwise modified, and how are they distributed in, around, and beneath the final crater?
What kinds of materials and structures are diagnostic of impact craters?
What are the characteristics of multi-ring basins, and how do they form?
How do the pressure and temperature conditions of shock metamorphism compare to thermal metamorphism on Earth?
Name and briefly describe shock metamorphic features in rocks and minerals.
How and why do the compositions of planetary atmospheres differ from that of Earth?
What determines whether an atmosphere is stable or unstable against vertical mixing?
How does global atmospheric circulation on different planets with atmospheres compare? What drives this circulation, and what modifies it?
How did the Earth originally acquire its volatile elements, and what evidence do we use to constrain the source of volatiles?
How are planetary atmospheres formed, and how might they evolve?
How does the greenhouse effect work, and why does atmospheric composition affect the surface temperatures on Earth and Venus?
What conditions are necessary for aeolian landscapes? Does your answer to this question differ between erosional and depositional landscapes? For different planets?
What information do aeolian landscapes provide? Does your answer to this question differ between erosional and depositional landscapes? For different planets?
How can aeolian landscapes be used to understand sediment transport paths?
How can aeolian landscapes be used to constrain atmospheric models?
Compare and contrast aeolian processes on Earth, Mars, Venus, and Titan.
What conditions are necessary for fluvial landscapes? Does your answer to this question differ between erosional and depositional landscapes? For different planets?
What information do fluvial landscapes provide? How does the type of information that can be derived from fluvial landscapes vary with resolution?
How can fluvial landscapes be used to constrain atmospheric models?
What is surprising about the appearance of meandering fluvial deposits on Mars?
Compare and contrast lakes, seas, and oceans on Earth, Mars, and Titan (e.g., composition, size, locations).
Why might we expect lacustrine deposits on Earth, Mars, and Titan to be similar? Why might we expect them to be different?
What is regolith, and how do its constituents and properties change with maturity?
Why is chemical weathering so limited in Solar System bodies?
What kinds of metamorphic rocks have been found on Mars? What do we surmise about metamorphism on Venus?
What is the heat source for thermal metamorphism and aqueous alteration on asteroids, and what accounts for one process or the other?
What is space weathering?
What kinds of planetary surface features are subject to mass wasting? What factors facilitate mass wasting?
What is the Last Universal Common Ancestor (LUCA), and how can we use it to develop targets for astrobiological research?
Why is carbon important for life, and how widespread are carbon compounds in the Universe?
What difficulties are faced when determining a biologic origin for Earth’s early life?
Why is the presence of organic matter not always an indication of the presence of life?
What lines of evidence can be used to argue for the astrobiological investigation of the moons Titan, Encedalus, and Europa?

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