Questions

Review Questions

Question 7.1

In what ways are the motions of Jupiter’s atmosphere like the motion of water stirred in a pot (see Figure 7-2b)? In what ways are they different?

Question 7.2

How do the swirling atmospheres of Jupiter and Saturn compare?

Question 7.3

What would happen if you tried to land a spacecraft on the surface of Jupiter?

Question 7.4

What are the belts and zones in the atmospheres of Jupiter and Saturn? Is the Great Red Spot more like a belt or a zone? Explain your answer.

Question 7.5

Describe the internal structures of Jupiter and Saturn, and compare them with the internal structure of Earth.

Question 7.6

Briefly describe the evidence supporting the idea that Uranus was struck by a large planetlike object several billion years ago.

Question 7.7

Describe the seasons on Uranus. In what ways are the Uranian seasons different from those on Earth?

Question 7.8

Why are Uranus and Neptune distinctly greenish-blue in color, while Jupiter and Saturn are not?

Question 7.9

How many rings encircle Saturn? Draw a sketch.

Question 7.10

If Saturn’s rings are not solid, why do they look solid when viewed through a telescope?

Question 7.11

Compare the rings that surround Jupiter, Saturn, Uranus, and Neptune. Briefly discuss their similarities and differences.

Web Chat Questions

Question 7.1

The classic science fiction films 2001: A Space Odyssey and 2010: The Year We Make Contact both involve manned spacecraft in orbit around Jupiter. What kinds of observations could humans make on such a mission that cannot be made by robotic spacecraft? What would be the risks associated with such a mission? Do you think that a manned Jupiter mission would be as worthwhile as a manned mission to Mars? Explain your answers.

Question 7.2

Suppose that Saturn were somehow moved to an orbit around the Sun with semimajor axis 1 AU, the same as Earth’s. Discuss what long-term effects this would have on the planet and its rings.

Question 7.3

Sir William Herschel, a British astronomer, discovered Uranus in 1781 and named it Georgium Sidus (Latin for “Georgian Star”), after the reigning monarch, George III. What name might Uranus have been given in 1781 if an astronomer in your country had discovered it? Why? What if it had been discovered in your country in 1881? In 1991?

Collaborative Exercises

Question 7.1

Using a ruler with millimeter markings on the first image of Jupiter in the text (Figure 7-1a), determine the ratio of the longest width of the Great Red Spot to the full diameter of Jupiter. Each group member should measure the image and all values should be averaged.

Question 7.2

The text provides different years that spacecraft have flown by Jupiter and Saturn. List these dates and create a time line by listing one important event that was occurring on Earth during each of those years.

Question 7.3

If the largest circle you can draw on a piece of paper represents the largest diameter of Saturn’s rings, about how large would Saturn be if scaled appropriately? Which item in a group member’s backpack is closest to this size?

Observing Questions

Question 7.1

Use Starry Night™ to examine the Jovian planets Jupiter, Saturn, Uranus, and Neptune. Select each of these planets from Favourites > Explorations. Use the location scroller to examine each planet from different views. (a) Describe each planet’s appearance. Which has the greatest color contrast in its cloud tops? (b) Which planet has the least color contrast in its cloud tops? (c) What can you say about the thickness of Saturn’s rings compared to their diameter?

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Question 7.2

Use Starry Night™ to examine Jupiter. Open Favourites > Explorations > Jupiter. Select Options > Solar System > Planets-Moons… from the menu. In the Planets-Moons Options dialog window, click the check box for Surface guides and click OK to remove the pole sticks and equator from the image. Click the Stop button and then use the Zoom controls and location scroller to examine Jupiter’s atmosphere. (a) Describe the appearance of the atmosphere of the planet. (b) Compare the number of white ovals and brown ovals in Jupiter’s southern hemisphere (the hemisphere in which the Great Red Spot is located) with the number of white ovals and brown ovals visible in the northern hemisphere. What general rule can you state about the abundance of these storms in the two hemispheres?

Question 7.3

Use Starry Night™ to observe the changing appearance of Saturn as seen from Earth. Select Favourites > Explorations > Atlas from the menu and click the Now button in the toolbar. Use the Find pane to locate and lock the view on Saturn (double-click the entry for Saturn). Zoom in until Saturn and its rings are clearly visible. Set the Time Flow Rate to 1 year. Now use the single-step forward button to observe the changing orientation of the rings as time advances in 1-year steps. (a) Describe qualitatively how the rings change orientation, as seen from Earth. (b) Use the Time controls to determine approximately how long it takes for Saturn’s rings, as seen from Earth, to go through a complete cycle from edge-on to fully open to edge-on to fully open and then finally to edge-on again. (c)Click the Now button to return to the present time. Use the Time controls to find when, within the next 30 years, Saturn’s rings will appear edge-on as seen from Earth. (d) Why do we see the orientation of Saturn’s rings change in the way that you found in part (b)?

Question 7.4

Use Starry Night™ to examine the rings of Saturn. Open Favourites > Explorations > Saturn and use the location scroller to view Saturn so that you are looking straight down on the plane of the rings. (a)Draw a copy of what you see and label the different rings and divisions. (b) Using the location scroller, adjust the view so that Saturn’s rings appear edge-on and then rotate the image until the Sun comes into view. Which of the following is correct? (i) The Sun is in the same plane as the rings of Saturn. (ii) The rings are in Saturn’s equatorial plane. (iii) Neither (i) nor (ii) is correct. (iv) Both (i) and (ii) are correct.