Moons of Giant Planets
Introduction
In this activity you will compare what you have learned about the major satellites of the giant planets, to each other and the Earth's Moon. This is an introduction to the study of "comparative paleontology" that I discussed in Lesson 1. This is useful for finding commonalities among the bodies of the Solar System. As you work on this activity you will:
a. compare and contrast the surface features of Jupiter's satellite Ganymede with those of the Moon.
b. discuss evidence of resurfacing and cratering on four of Saturn's regular satellites.
c. compare and contrast surface features of Saturn's regular satellite, Titan, to similar ones on Earth.
d. compare the evidence for the reprocessing of part of Neptune's satellite, Triton.
Examine each image carefully. In your post, respond briefly to the questions for each section (1pts each).
Ganymede (Jupiter's satellite)
The figures below show the Earth's Moon (left) and Ganymede (right) side by side. Note that the images are not to scale. The Moon's is 3474 km in diameter and Ganymede is nearly double that at 5268 km. If you feel the images on this activity are insufficient for you to answer the questions (need higher resolution or better color contrast, etc) feel free to use Google Images to look up more images of the objects in question.
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1. Name two surface features that Ganymede appears to have in common with the Moon.
2. In what ways are these features similar? In what ways must the origins of the features on Ganymede be different?
Satellites of Saturn
As discussed in this lesson, Saturn has dozens of satellites, both regular and irregular. The following images shows four of Saturn's regular satellites. The images are not to scale. The diameters of each satellite are listed along with the satellite's name: Enceladus (top left, ~600 km), Dione (top right, ~1100 km), Rhea (bottom left, ~1500 km), and Mimas (bottom right, ~500 km).
Study the images and make note of the amount of cratering, unusual terrain, coloring and so on of each satellite. Are any of these surface features uniform among these satellites? Recall what you have learned about the probable past evolution of each of these satellites and answer the following questions:
3. Which satellite(s) experienced resurfacing? Describe the evidence.
4. Are there areas of crater saturation on any of these four satellites? Which one(s) and on what part?
5. In general, are there regions on any of these satellites where one could assume the surface is younger or older compared to regions of Earth’s Moon? Explain your reasoning.
Saturn’s Satellite with Liquid on its Surface: Titan
Even though Titan is a satellite and is about 1.5 times the diameter of the Moon, it is more interesting and relevant as you've learned, to compare Titan's surface features with those of Earth. Earth's average surface temperature is about 290 K; Titan's is about 94 K! The Cassini spacecraft, which orbits Saturn and passes by its satellites, used infrared and radar instruments to map most of Titan's surface. You were introduced to a large number of features that have analogies on Earth. Lets take a look at the most interesting - lakes and tributary networks.
6. The images above are from two different worlds. The image at left shows a lake (at different resolutions) located in the polar region on Titan, while the image at right shows Lake Superior on Earth. For the pair of images shown, list a few things that look very similar and a few that are quite different.
Triton: The Largest Moon of Neptune
The Voyager spacecraft found evidence of the reprocessing of Triton's surface as shown in the image below.
7. Describe the two different regions of Triton.
8. What is the evidence that Triton’s surface has been reprocessed?
The image of Triton below shows a plain of ice. The plain was probably formed by eruptions of water or water-ammonia slurry. It seems to fill the remains of ancient impact basins. Given what you understand about the modification of Triton's surface, answer the following two questions.
9. What region(s) on our Moon are similar in origin?
10. What is one major difference between the formation of this plain and those similar features on the Moon?
As with previous discussion forums, a full credit response must include brief but clear and thoughtful responses to all 10 questions and at least one constructive comment and at least one attempted answer to a fellow student's post.
Please note, you will not be able to see other's posts until you have submitted your own answers.
Credits:
Activity adapted from "Learning Astronomy by Doing Astronomy: Collaborative Lecture Activities" by Stacy Palen and Ana M. Larson
Image 1 - "FullMoon2010" by Gregory H. Revera - Own work. Licensed under CC BY-SA 3.0 via Commons - https://commons.wikimedia.org/wiki/File:FullMoon2010.jpg#/media/File:FullMoon2010.jpg (Links to an external site.)
Image 2 - "Ganymede-moon" by NASA/JPL/DLR - Ganymede's Trailing Hemisphere. Licensed under Public Domain via Commons - https://commons.wikimedia.org/wiki/File:Ganymede-moon.jpg#/media/File:Ganymede-moon.jpg (Links to an external site.)
Image 3 - "PIA17202 - Approaching Enceladus" by National Aeronautics and Space Administration (NASA) / Jet Propulsion Laboratory (JPL) - PIA17202 from the NASA/JPL Photojournal. Licensed under Public Domain via Commons - https://commons.wikimedia.org/wiki/File:PIA17202_-_Approaching_Enceladus.jpg#/media/File:PIA17202_-_Approaching_Enceladus.jpg (Links to an external site.)
Image 3 - "Dione in natural light" by NASA - http://photojournal.jpl.nasa.gov/catalog/PIA09861. Licensed under Public Domain via Commons - https://commons.wikimedia.org/wiki/File:Dione_in_natural_light.jpg#/media/File:Dione_in_natural_light.jpg (Links to an external site.)
Image 4 - "PIA07763 Rhea full globe5" by NASA/JPL/Space Science Institute - http://photojournal.jpl.nasa.gov/catalog/PIA07763. Licensed under Public Domain via Commons - https://commons.wikimedia.org/wiki/File:PIA07763_Rhea_full_globe5.jpg#/media/File:PIA07763_Rhea_full_globe5.jpg (Links to an external site.)
Image 5 - "Mimas Cassini" by NASA / JPL-Caltech / Space Science Institute - http://www.nasa.gov/mission_pages/cassini/multimedia/pia12570.htmlhttp://photojournal.jpl.nasa.gov/catalog/PIA12570This image or video was catalogued by Jet Propulsion Laboratory of the United States National Aeronautics and Space Administration (NASA) under Photo ID: PIA12570.This tag does not indicate the copyright status of the attached work. A normal copyright tag is still required. See Commons:Licensing for more information.Licensed under Public Domain via Commons - https://commons.wikimedia.org/wiki/File:Mimas_Cassini.jpg#/media/File:Mimas_Cassini.jpg (Links to an external site.)
Image 6 - "PIA19052-SaturnMoon-Titan-LigeiaMare-SAR&DespeckledViews-20150212" by NASA/JPL-Caltech/ASI - http://photojournal.jpl.nasa.gov/jpeg/PIA19052.jpg. Licensed under Public Domain via Commons - https://commons.wikimedia.org/wiki/File:PIA19052-SaturnMoon-Titan-LigeiaMare-SAR%26DespeckledViews-20150212.jpg#/media/File:PIA19052-SaturnMoon-Titan-LigeiaMare-SAR%26DespeckledViews-20150212.jpg (Links to an external site.)
Image 7 - "Lake Superior NASA". Licensed under Public Domain via Commons - https://commons.wikimedia.org/wiki/File:Lake_Superior_NASA.jpg#/media/File:Lake_Superior_NASA.jpg (Links to an external site.)
Image 8 - "Triton moon mosaic Voyager 2 (large)" by NASA / Jet Propulsion Lab / U.S. Geological Survey - http://photojournal.jpl.nasa.gov/catalog/PIA00317. Licensed under Public Domain via Commons - https://commons.wikimedia.org/wiki/File:Triton_moon_mosaic_Voyager_2_(large).jpg#/media/File:Triton_moon_mosaic_Voyager_2_(large).jpg (Links to an external site.)
Image 9 - NASA/JPL http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA12186 (Links to an external site.)
Many thanks to Stacey Davis for converting activities to Word Docs!