Geol 109 Final Exam Questions And Detailed Correct Answers.

Which of the following is most important in keeping water a liquid on Earth? - correct answers The distance from the Sun Why are the planetary bodies of the inner solar system different in composition from those of the outer solar system? (Select all that apply.) - correct answers The planets formed in a thermal gradient around the ancient Sun, high-temperature solids could form near the ancient Sun, large icy cores attracted hydrogen and helium from the nebula. Which statement is an accurate general history of cratering on a planet? - correct answers Early heavy cratering with declining intensity, then intense bombardment, then declining intensity to the present. As a dense particle in a planet moves toward the core, the loss of gravitational potential energy is converted to _________ energy. - correct answers Thermal (heat) In what way is Earth's atmosphere unique among the moons and planets? - correct answers It is rich in oxygen (O2). The absence of large folded mountain systems on the Moon, Mars, and Mercury is evidence that the lithospheres of these planets ___________________. - correct answers Thickened rapidly as these worlds cooled. Why aren't running water and erosion important geologic agents on all planets? (Select all that apply.) - correct answers Some planets lack solid surfaces, some planets are too cold, some planets have the wrong composition for water to exist, some planets are too hot. Suppose that a new planet has been discovered between Venus and Earth. It is about the size of Earth's Moon. Which of the following statements about it is probably true? - correct answers It should be intensely cratered and lack a thick atmosphere. Which of the following planetary bodies has the oldest surface? - correct answers The Moon. What is the most important control on a planet's present level of geologic activity (especially volcanism and tectonism)? - correct answers The thickness of its lithosphere. Why are comets thought to have originated in a different part of the solar nebula than asteroids? - correct answers Because they are composed mostly of ices. Which of the following are important components of a comet? (Select all that apply.) - correct answers Water ice, silicate materials like olivine, methane, ammonia, carbon dioxide and carbon monoxide The nucleus of a comet __________________. - correct answers Is small and dark. Comets glow in the night sky because __________________________. - correct answers They reflect the light from the Sun. The tail of a comet __________________. - correct answers Develops temporarily when the comet enters the inner solar system. Is this comet near the Sun (within the orbit of Jupiter)? - correct answers Yes. What is the origin of the light-colored streaks extending from the surface of comet Churyumov-Gerasimenko? - correct answers The streaks are plumes of dust and gas ejected from the interior as the Sun heats it. Which is true of comet Churyumov Gerasimenko (67P - see image above)? (Select all that apply.) - correct answers It is very dark because of the presence of organics, it is extremely low in density, suggesting pore space inside. The Oort cloud _____________________. - correct answers Contains the orbits of comets in the outer part of the solar system. In which ways is the Oort cloud different than the Kuiper belt? (Select all that apply.) - correct answers The Oort cloud is spherical, not disk-shaped, most long period comets come from the Oort cloud. Pluto is considered to be a dwarf planet by many astronomers. Why? - correct answers Because it has not cleared its orbital path of debris. Which statements are true for the Kuiper belt? (Select all that apply.) - correct answers It contains many small icy objects in orbit around the Sun, the orbits formed a flattened disk in the outer solar system, Pluto is one of the bodies in the Kuiper belt. Based on what we know today, which of the following is most like Pluto in its size, composition, and density? - correct answers Triton Pluto's atmosphere is tenuous and temporary, but what are its major constituents? - correct answers Nitrogen and methane that sublime from the most volatile ices on its surface. How did the polygonal shapes on Pluto's Sputnik Planitia form? - correct answers By convection within the glacial ice. The tall mountains on Pluto are composed of what kind of ice? - correct answers Water How did Pluto's Sputnik Planitia form? - correct answers A large impact basin was filled with weak nitrogen ice. What do the arrows in this image show? - correct answers Glacial flow directions The dark reddish regions on Charon's north pole result from what process? - correct answers Methane and organic molecular deposits from Pluto that condense at Charon's poles. Why is Neptune blue? - correct answers Because its atmosphere contains a significant proportion of methane. Both Neptune and Uranus have magnetic fields that ___________________. - correct answers Are tilted with respect to the axis of rotation. In contrast to Jupiter, Uranus and Neptune are thought to ________________________. - correct answers Have abundant water in their interiors. In the early 1980's, some planetary scientists suggested that Triton has a sea of liquid nitrogen. Voyager 2 showed that _____________________________. - correct answers Triton is too cold for liquid nitrogen. In what way is the orbit of Triton distinctive? - correct answers It is retrograde. Triton, because of its small size and frigid surface, was thought to be an unlikely spot for recent geologic activity. What did Voyager 2 reveal? (Select all that apply.) - correct answers Triton has many young surfaces and active "volcanic" vents, Triton was probably heated by tidal activity. Which letter on this image of Triton labels the youngest area of icy volcanism? Click on your answer. - correct answers B (top right greenish area). Which letter on this image of Triton marks an area that has a composition like Earth's atmosphere? Click on your answer. - correct answers D (bottom left spotty area). These are images of two of Neptune's moons. In the photos, both are about the same size; in reality, one has a much larger diameter. Which one is larger? Click on your answer. - correct answers Triton. Why is Uranus considered so odd compared to other planets? - correct answers Its spin axis is tipped from vertical by over 90 degrees. In what way is the magnetic field of Uranus distinctive? Choose all that apply. - correct answers It has an unexpected orientation, it is tilted compared to the spin axis, it is irregular and may be experiencing a reversal. Why is Uranus so much smaller than Saturn and Jupiter? - correct answers There was not enough nebular gas and dust near the region where Uranus formed. The particles in the rings of Uranus are ______________________. - correct answers Dark and probably composed of darkened methane ice. In what way are the icy moons of Uranus different from those of Saturn? - correct answers Slightly higher densities. Which of the following is a common process that occurred during the evolution of the satellites of Uranus? - correct answers Cracking as they expanded late in their histories The last 2 or 3 billion years of the histories of the small inner planets (like the Moon and Mercury) are dominated by contraction, whereas the late histories of the small icy satellites of Saturn and Uranus are