Lec24-Apr16 - Key Concepts •  Moon: craters,...

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Unformatted text preview: 4/16/10 Key Concepts •  Moon: craters, maria Astro 109 Lecture 24: Geology on Terrestrial Planets •  Mercury: craters, scarps, iron core •  Venus: some craters, volcanoes, “flake” tectonics April 16 •  Mars: some craters, volcanoes, Valles Marineris, past water Apr. 16 Geological processes Ejecta rays Volcanism Cratering Erosion Tectonics Apr. 16 Apr. 16 http://antwrp.gsfc.nasa.gov/apod/ap010809.html" Central peak Moon Discussion QuesZon Astronaut footprints on the Moon will probably A.  exist for >10,000 years because there is very liQle weathering on the Moon. B.  exist for >10,000 years because the Moon’s surface is so hard and durable. C.  be eliminated in <10,000 years by wind erosion. D.  be eliminated in <10,000 years by large numbers of meteor impacts. E.  None of the above; the footprints are already gone. Apr. 16 Apr. 16 1 4/16/10 Discussion QuesZon How did the lunar maria form? A.  Large impacts fractured the Moon’s lithosphere, and lava later filled the impact basins. B.  The maria are the result of gradual erosion by micrometeorites striking the Moon. C.  VolaZle gases escaping from the Moon’s interior heated and eroded the surface in the regions of the maria. D.  The maria were the seabeds of ancient oceans that once existed but have since evaporated. E.  The maria are the remnants of spaceports built by aliens visiZng the solar system. Apr. 16 Apr. 16 Lunar cratering history Apr. 16 Apr. 16 FormaZon of the Moon Apr. 16 Mercury Apr. 16 http://www.boston.com/bigpicture/2009/06/mercury_and_messenger.html" 2 4/16/10 Ejecta rays Discussion QuesZon A geological process that has altered the surface of Mercury but not the surface of the Moon is A.  B.  C.  D.  E.  Apr. 16 lava flows that created smooth regions. impacts that created craters. thrust faults that created cliffs. water erosion. plate tectonics. Apr. 16 Scarps Discussion QuesZon The scarps on Mercury indicate that •  cliffs hundreds of m high and hundreds of km long •  essenZally wrinkles! •  unique to Mercury? Apr. 16 A.  B.  C.  D.  E.  Mercury had running water at some Zme in its past. most of Mercury’s craters are volcanic in origin. Mercury shrank ader its crust solidified. most of Mercury’s surface is <100 million years old. Mercury now has acZve plate tectonics. Apr. 16 Radar map from Magellan Apr. 16 Apr. 16 3 4/16/10 Topographic map of Venus Impact craters on Venus Radar images from Magellan spacecrad Again from Magellan. Apr. 16 Apr. 16 New evidence for “recent” volcanism http://www.nytimes.com/2010/04/10/science/space/10venus.html" From Venus Express Apr. 16 Apr. 16 Hawaii Discussion QuesZon Volcanic chains on Earth Why do volcanoes on Venus tend to be fewer and larger than those on Earth? A.  B.  C.  D.  E.  Venus has more ongoing volcanic erupZons than Earth. Venus has more erosion than Earth. Venus has a thinner atmosphere than Earth. Venus has a hoQer interior than Earth. Venus does not have plate tectonics. •  plate slides over hot spot  ­ ­> chain of volcanoes Apr. 16 Apr. 16 http://www.fathom.com/feature/122477/index.html" 4 4/16/10 “Flake” tectonics on Venus Plate tectonics on Earth Apr. 16 Apr. 16 Topographic map of Mars Mars Apr. 16 Apr. 16 Discussion QuesZon Valles Marineris on Mars is labeled a rid valley. Which of the following is a similar type of feature on Earth? A. volcano C. Red Sea Apr. 16 B. Himalayas D. Grand Canyon Apr. 16 5 4/16/10 Mamers Vallis Standing water? Running water From orbit From the ground Ares Vallis Ganges Chasma Apr. 16 Hephaestus Fossae Mars Express, ESA / DLR / FU Berlin Mars Odyssey, NASA / JPL / Arizona State University Left – http://science.nasa.gov/science-news/science-at-nasa/2000/ast04dec_2/" Apr. 16 Right – NASA/JPL/Cornell, http://www.space.com/scienceastronomy/hematite_blueberries_040319.html" HW quesZons HW quesZons Chapter 10 Chapter 11 7. Are impact craters on the Moon the same size as the meteroids that made the impact? Explain your answer. 11. What kind of surface features are found on Mercury? How do they compare to surface features on the Moon? Why are they probably much older than most surface features on the Earth? 8. Describe the differences between the maria and the lunar highlands. Which kind of terrain covers more of the Moon’s surface? Which kind of terrain is more heavily cratered? Which kind of terrain was formed later in the Moon’s history? How do we know? 29. Temperature variaZons between day and night are much more severe on the Moon than on Earth. Explain why. Apr. 16 13. If Mercury is the closest planet to the Sun and has such a high average surface temperature, how is it possible that ice might exist on its surface? 65. (a) The Grand Canyon in Arizona was formed over 15 to 20 million years by the flowing waters of the Colorado River, as well as by rain and wind. Contrast this formaZon scenario to that of Valles Marineris on Mars. (b) Valles Marineris is someZmes called “the Grand Canyon of Mars.” Is this an appropriate descripZon? Why or why not? Apr. 16 6 ...
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This note was uploaded on 09/15/2011 for the course PHYS 109 taught by Professor Pryor during the Spring '09 term at Rutgers.

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