Horizons Exploring the Universe 13th edition

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Michael Seeds and Dana Backman
Publisher: Cengage Learning

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  • Chapter 1: Here and Now
    • 1: Active Figures
    • 1: General Problem (4)
    • 1: End of Chapter Problem (8)
    • 1: Review Exercise (14)
    • 1: End of Chapter Review Question (8)
    • 1: Ranking Task Exercise (2)
    • 1: Learning to Look (2)
    • 1: Animation Tutorial

  • Chapter 2: A User's Guide to the Sky
    • 2: Active Figures
    • 2: General Problem (5)
    • 2: End of Chapter Problem (5)
    • 2: Review Exercise (17)
    • 2: End of Chapter Review Question (6)
    • 2: Ranking Task Exercise (1)
    • 2: Learning to Look (1)
    • 2: Animation Tutorial (2)

  • Chapter 3: Cycles of the Sun and Moon
    • 3: Active Figures
    • 3: General Problem (7)
    • 3: End of Chapter Problem (5)
    • 3: Review Exercise (28)
    • 3: End of Chapter Review Question (1)
    • 3: Ranking Task Exercise (4)
    • 3: Learning to Look (1)
    • 3: Animation Tutorial (7)

  • Chapter 4: The Origin of Modern Astronomy
    • 4: Active Figures
    • 4: General Problem (8)
    • 4: End of Chapter Problem (6)
    • 4: Review Exercise (37)
    • 4: End of Chapter Review Question (2)
    • 4: Ranking Task Exercise (2)
    • 4: Learning to Look (2)
    • 4: Animation Tutorial (4)

  • Chapter 5: Light and Telescopes
    • 5: Active Figures
    • 5: General Problem (5)
    • 5: End of Chapter Problem (10)
    • 5: Review Exercise (24)
    • 5: End of Chapter Review Question (16)
    • 5: Ranking Task Exercise (2)
    • 5: Learning to Look (2)
    • 5: Animation Tutorial (2)

  • Chapter 6: Atoms and Spectra
    • 6: Active Figures
    • 6: General Problem (4)
    • 6: End of Chapter Problem (8)
    • 6: Review Exercise (20)
    • 6: End of Chapter Review Question (12)
    • 6: Ranking Task Exercise
    • 6: Learning to Look (2)
    • 6: Animation Tutorial (2)

  • Chapter 7: The Sun
    • 7: Active Figures
    • 7: General Problem (3)
    • 7: End of Chapter Problem (10)
    • 7: Review Exercise (24)
    • 7: End of Chapter Review Question (16)
    • 7: Ranking Task Exercise (2)
    • 7: Learning to Look (2)
    • 7: Animation Tutorial (3)

  • Chapter 8: The Family of Stars
    • 8: Active Figures
    • 8: General Problem (5)
    • 8: End of Chapter Problem (12)
    • 8: Review Exercise (25)
    • 8: End of Chapter Review Question (17)
    • 8: Ranking Task Exercise (5)
    • 8: Learning to Look (1)
    • 8: Animation Tutorial (2)

  • Chapter 9: The Formation and Structure of Stars
    • 9: Active Figures
    • 9: General Problem (5)
    • 9: End of Chapter Problem (14)
    • 9: Review Exercise (36)
    • 9: End of Chapter Review Question (7)
    • 9: Ranking Task Exercise (2)
    • 9: Learning to Look (2)
    • 9: Animation Tutorial (7)

  • Chapter 10: The Deaths of Stars
    • 10: Active Figures
    • 10: General Problem (5)
    • 10: End of Chapter Problem (2)
    • 10: Review Exercise (34)
    • 10: End of Chapter Review Question (1)
    • 10: Ranking Task Exercise (4)
    • 10: Learning to Look (2)
    • 10: Animation Tutorial (6)

  • Chapter 11: Neutron Stars and Black Holes
    • 11: Active Figures
    • 11: General Problem (3)
    • 11: End of Chapter Problem (9)
    • 11: Review Exercise (24)
    • 11: End of Chapter Review Question (13)
    • 11: Ranking Task Exercise (2)
    • 11: Learning to Look (2)
    • 11: Animation Tutorial (3)

  • Chapter 12: The Milky Way Galaxy
    • 12: Active Figures
    • 12: General Problem (4)
    • 12: End of Chapter Problem (9)
    • 12: Review Exercise (24)
    • 12: End of Chapter Review Question (3)
    • 12: Ranking Task Exercise (2)
    • 12: Learning to Look (2)
    • 12: Animation Tutorial (2)

  • Chapter 13: Galaxies: Normal and Active
    • 13: Active Figures
    • 13: General Problem (5)
    • 13: End of Chapter Problem (10)
    • 13: Review Exercise (44)
    • 13: End of Chapter Review Question (6)
    • 13: Ranking Task Exercise (4)
    • 13: Learning to Look (2)
    • 13: Animation Tutorial (1)

  • Chapter 14: Modern Cosmology
    • 14: Active Figures
    • 14: General Problem (3)
    • 14: End of Chapter Problem (7)
    • 14: Review Exercise (25)
    • 14: End of Chapter Review Question (9)
    • 14: Ranking Task Exercise (2)
    • 14: Learning to Look (1)
    • 14: Animation Tutorial (3)

  • Chapter 15: Origin of the Solar System and Extrasolar Planets
    • 15: Active Figures
    • 15: General Problem (4)
    • 15: End of Chapter Problem (9)
    • 15: Review Exercise (24)
    • 15: End of Chapter Review Question (18)
    • 15: Ranking Task Exercise (3)
    • 15: Learning to Look (2)
    • 15: Animation Tutorial (1)

  • Chapter 16: Earth and Moon: Bases for Comparative Planetology
    • 16: Active Figures
    • 16: General Problem (3)
    • 16: End of Chapter Problem (5)
    • 16: Review Exercise (34)
    • 16: End of Chapter Review Question
    • 16: Ranking Task Exercise (3)
    • 16: Learning to Look (3)
    • 16: Animation Tutorial (3)

  • Chapter 17: Mercury, Venus, and Mars
    • 17: Active Figures
    • 17: General Problem (3)
    • 17: End of Chapter Problem (4)
    • 17: Review Exercise (27)
    • 17: End of Chapter Review Question (1)
    • 17: Ranking Task Exercise (3)
    • 17: Learning to Look (2)
    • 17: Animation Tutorial

  • Chapter 18: The Outer Solar System
    • 18: Active Figures
    • 18: General Problem (7)
    • 18: End of Chapter Problem (5)
    • 18: Review Exercise (43)
    • 18: End of Chapter Review Question
    • 18: Ranking Task Exercise (4)
    • 18: Learning to Look (3)
    • 18: Animation Tutorial (4)

  • Chapter 19: Meteoroids, Meteors, and Meteorites
    • 19: Active Figures
    • 19: General Problem (4)
    • 19: End of Chapter Problem (8)
    • 19: Review Exercise (24)
    • 19: End of Chapter Review Question (1)
    • 19: Ranking Task Exercise (2)
    • 19: Learning to Look (3)
    • 19: Animation Tutorial (2)

  • Chapter 20: Astrobiology: Life on Other Worlds
    • 20: Active Figures
    • 20: General Problem (3)
    • 20: End of Chapter Problem (8)
    • 20: Review Exercise (25)
    • 20: End of Chapter Review Question (14)
    • 20: Ranking Task Exercise (2)
    • 20: Learning to Look (1)
    • 20: Animation Tutorial (2)

New to this edition are animation tutorials written exclusively for Horizons by text author Mike Seeds. These tutorials will help students review important concepts and explore topics from the textbook in more detail. Each tutorial requires a student to consider or manipulate an animation in order to answer a series of questions. Hints are offered with each step, which encourages students to think through each question. Animation tutorials will build student reasoning so they will ultimately be able to draw conclusions.

Questions Available within WebAssign

Most questions from this textbook are available in WebAssign. The online questions are identical to the textbook questions except for minor wording changes necessary for Web use. Whenever possible, variables, numbers, or words have been randomized so that each student receives a unique version of the question. This list is updated nightly.

Question Group Key
AT - Animation Tutorial
GP - General Problem
LL - Learning to Look
P - Problem
RE - Review Exercise
RQ - Review Question
RTE - Ranking Task Exercise
XP - Extra Problem


Question Availability Color Key
BLACK questions are available now
GRAY questions are under development


Group Quantity Questions
Chapter 1: Here and Now
1.GP 4 XP.001 XP.002 XP.003 XP.004
1.LL 2 XP.001 XP.003
1.P 8 003 004 005 006 007 008 009 010
1.RE 14 XP.001 XP.002 XP.003 XP.004 XP.005 XP.006 XP.007 XP.008 XP.009 XP.010 XP.011 XP.012 XP.013 XP.014
1.RQ 8 001 002 003 004 005 006 007 008
1.RTE 2 XP.001 XP.002
Chapter 2: A User's Guide to the Sky
2.AT 2 001 002
2.GP 5 XP.001 XP.002 XP.003 XP.004 XP.01a
2.LL 1 XP.001
2.P 5 001 002 003 004 005
2.RE 17 XP.001 XP.002 XP.003 XP.004 XP.005 XP.006 XP.007 XP.008 XP.009 XP.010 XP.011 XP.012 XP.013 XP.014 XP.015 XP.016 XP.017
2.RQ 6 005 006 007 010 011 014
2.RTE 1 XP.001
Chapter 3: Cycles of the Sun and Moon
3.AT 7 001 002 003 004 005 006 007
3.GP 7 XP.001 XP.002 XP.003 XP.004 XP.005 XP.006 XP.007
3.LL 1 XP.002
3.P 5 002 003 004 007 008
3.RE 28 XP.001 XP.002 XP.003 XP.004 XP.005 XP.006 XP.007 XP.008 XP.009 XP.010 XP.011 XP.012 XP.013 XP.014 XP.015 XP.016 XP.017 XP.018 XP.019 XP.020 XP.021 XP.022 XP.023 XP.024 XP.025 XP.026 XP.027 XP.028
3.RQ 1 004
3.RTE 4 XP.001 XP.002 XP.003 XP.004
Chapter 4: The Origin of Modern Astronomy
4.AT 4 002 003 004 005
4.GP 8 XP.001 XP.002 XP.003 XP.004 XP.005 XP.006 XP.007 XP.008
4.LL 2 XP.001 XP.003
4.P 6 001 002 003 004 005 006
4.RE 37 XP.001 XP.002 XP.003 XP.004 XP.005 XP.006 XP.007 XP.008 XP.009 XP.010 XP.011 XP.012 XP.013 XP.014 XP.015 XP.016 XP.017 XP.018 XP.019 XP.020 XP.021 XP.022 XP.023 XP.024 XP.025 XP.026 XP.027 XP.028 XP.029 XP.030 XP.031 XP.032 XP.033 XP.034 XP.035 XP.036 XP.037
4.RQ 2 007 013
4.RTE 2 XP.001 XP.002
Chapter 5: Light and Telescopes
5.AT 2 001 002
5.GP 5 XP.001 XP.002 XP.003 XP.004 XP.005
5.LL 2 XP.001 XP.003
5.P 10 001 002 003 004 005 006 007 008 009 010
5.RE 24 XP.001 XP.002 XP.003 XP.004 XP.005 XP.006 XP.007 XP.008 XP.009 XP.010 XP.011 XP.012 XP.013 XP.014 XP.015 XP.016 XP.017 XP.018 XP.019 XP.020 XP.021 XP.022 XP.023 XP.024
5.RQ 16 XP.001 XP.002 XP.003 001 002 003 004 005 006 007 008 009 010 011 012 013
5.RTE 2 XP.001 XP.002
Chapter 6: Atoms and Spectra
6.AT 2 001 002
6.GP 4 XP.001 XP.002 XP.003 XP.004
6.LL 2 XP.003 XP.004
6.P 8 001 002 003 004 005 006 007 008
6.RE 20 XP.001 XP.002 XP.003 XP.004 XP.005 XP.006 XP.007 XP.008 XP.009 XP.010 XP.011 XP.012 XP.013 XP.014 XP.015 XP.016 XP.017 XP.018 XP.019 XP.020
6.RQ 12 001 002 003 004 005 006 007 008 009 010 011 012
Chapter 7: The Sun
7.AT 3 001 002 003
7.GP 3 XP.001 XP.002 XP.003
7.LL 2 XP.002 XP.003
7.P 10 001 002 003 004 005 006 007 008 009 010
7.RE 24 XP.001 XP.002 XP.003 XP.004 XP.005 XP.006 XP.007 XP.008 XP.009 XP.010 XP.011 XP.012 XP.013 XP.014 XP.015 XP.016 XP.017 XP.018 XP.019 XP.020 XP.021 XP.022 XP.023 XP.024
7.RQ 16 001 002 003 004 005 006 007 008 009 010 011 012 013 014 015 016
7.RTE 2 XP.001 XP.002
Chapter 8: The Family of Stars
8.AT 2 001 003
8.GP 5 XP.001 XP.002 XP.003 XP.004 XP.005
8.LL 1 XP.002
8.P 12 001 002 003 004 006 007 008 009 010 011 012 013
8.RE 25 XP.001 XP.002 XP.003 XP.004 XP.005 XP.006 XP.007 XP.008 XP.009 XP.010 XP.011 XP.012 XP.013 XP.014 XP.015 XP.016 XP.017 XP.018 XP.019 XP.020 XP.021 XP.022 XP.023 XP.024 XP.025
8.RQ 17 001 002 003 004 005 006 007 008 010 011 012 013 014 015 016 017 018
8.RTE 5 XP.001 XP.002 XP.003 XP.004 XP.005
Chapter 9: The Formation and Structure of Stars
9.AT 7 001 002 003 004 005 006 007
9.GP 5 XP.001 XP.002 XP.003 XP.004 XP.005
9.LL 2 XP.001 XP.002
9.P 14 001 002 003 005 006 007 008 010 011 012 013 014 015 016
9.RE 36 XP.001 XP.002 XP.003 XP.004 XP.005 XP.006 XP.007 XP.008 XP.009 XP.010 XP.011 XP.012 XP.013 XP.014 XP.015 XP.016 XP.017 XP.018 XP.019 XP.020 XP.021 XP.022 XP.023 XP.024 XP.025 XP.026 XP.027 XP.028 XP.029 XP.030 XP.031 XP.032 XP.033 XP.034 XP.035 XP.036
9.RQ 7 002 010 011 013 015 018 020
9.RTE 2 XP.001 XP.002
Chapter 10: The Deaths of Stars
10.AT 6 001 002 003 004 005 006
10.GP 5 XP.001 XP.002 XP.003 XP.004 XP.005
10.LL 2 XP.002 XP.003
10.P 2 002 005
10.RE 34 XP.001 XP.002 XP.003 XP.004 XP.005 XP.006 XP.007 XP.008 XP.009 XP.010 XP.011 XP.012 XP.013 XP.014 XP.015 XP.016 XP.017 XP.018 XP.019 XP.020 XP.021 XP.022 XP.023 XP.024 XP.025 XP.026 XP.027 XP.028 XP.029 XP.030 XP.031 XP.032 XP.033 XP.034
10.RQ 1 003
10.RTE 4 XP.001 XP.002 XP.003 XP.004
Chapter 11: Neutron Stars and Black Holes
11.AT 3 001 002 003
11.GP 3 XP.001 XP.002 XP.003
11.LL 2 XP.001 XP.002
11.P 9 001 002 003 004 005 006 007 008 009
11.RE 24 XP.001 XP.002 XP.003 XP.004 XP.005 XP.006 XP.007 XP.008 XP.009 XP.010 XP.011 XP.012 XP.013 XP.014 XP.015 XP.016 XP.017 XP.018 XP.019 XP.020 XP.021 XP.022 XP.023 XP.024
11.RQ 13 001 002 003 004 005 006 007 008 009 010 011 012 015
11.RTE 2 XP.001 XP.002
Chapter 12: The Milky Way Galaxy
12.AT 2 001 002
12.GP 4 XP.001 XP.002 XP.003 XP.004
12.LL 2 XP.001 XP.002
12.P 9 001 002 003 004 005 006 007 009 010
12.RE 24 XP.001 XP.002 XP.003 XP.004 XP.005 XP.006 XP.007 XP.008 XP.009 XP.010 XP.011 XP.012 XP.013 XP.014 XP.015 XP.016 XP.017 XP.018 XP.019 XP.020 XP.021 XP.022 XP.023 XP.024
12.RQ 3 003 005 008
12.RTE 2 XP.001 XP.002
Chapter 13: Galaxies: Normal and Active
13.AT 1 004
13.GP 5 XP.001 XP.002 XP.003 XP.004 XP.005
13.LL 2 XP.003 XP.004
13.P 10 001 002 003 004 005 006 007 008 009 010
13.RE 44 XP.001 XP.002 XP.003 XP.004 XP.005 XP.006 XP.007 XP.008 XP.009 XP.010 XP.011 XP.012 XP.013 XP.014 XP.015 XP.016 XP.017 XP.018 XP.019 XP.020 XP.021 XP.022 XP.023 XP.024 XP.025 XP.026 XP.027 XP.028 XP.029 XP.030 XP.031 XP.032 XP.033 XP.034 XP.035 XP.036 XP.037 XP.038 XP.039 XP.040 XP.041 XP.042 XP.043 XP.044
13.RQ 6 002 003 007 008 009 010
13.RTE 4 XP.001 XP.002 XP.003 XP.004
Chapter 14: Modern Cosmology
14.AT 3 001 002 003
14.GP 3 XP.001 XP.002 XP.003
14.LL 1 XP.001
14.P 7 001 002 003 004 005 006 007
14.RE 25 XP.001 XP.002 XP.003 XP.004 XP.005 XP.006 XP.007 XP.008 XP.009 XP.010 XP.011 XP.012 XP.013 XP.014 XP.015 XP.016 XP.017 XP.018 XP.019 XP.020 XP.021 XP.022 XP.023 XP.024 XP.025
14.RQ 9 001 002 003 004 005 006 007 008 012
14.RTE 2 XP.001 XP.002
Chapter 15: Origin of the Solar System and Extrasolar Planets
15.AT 1 001
15.GP 4 XP.001 XP.002 XP.003 XP.004
15.LL 2 XP.001 XP.002
15.P 9 001 002 003 004 005 006 007 008 009
15.RE 24 XP.001 XP.002 XP.003 XP.004 XP.005 XP.006 XP.007 XP.008 XP.009 XP.010 XP.011 XP.012 XP.013 XP.014 XP.015 XP.016 XP.017 XP.018 XP.019 XP.020 XP.021 XP.022 XP.023 XP.024
15.RQ 18 001 002 003 004 005 006 007 008 009 010 011 012 013 014 015 016 017 018
15.RTE 3 XP.001 XP.002 XP.003
Chapter 16: Earth and Moon: Bases for Comparative Planetology
16.AT 3 001 002 003
16.GP 3 XP.001 XP.002 XP.003
16.LL 3 XP.002 XP.003 XP.004
16.P 5 002 003 004 005 007
16.RE 34 XP.001 XP.002 XP.003 XP.004 XP.005 XP.006 XP.007 XP.008 XP.009 XP.010 XP.011 XP.012 XP.013 XP.014 XP.015 XP.016 XP.017 XP.018 XP.019 XP.020 XP.021 XP.022 XP.023 XP.024 XP.025 XP.026 XP.027 XP.028 XP.029 XP.030 XP.031 XP.032 XP.033 XP.034
16.RTE 3 XP.001 XP.002 XP.003
Chapter 17: Mercury, Venus, and Mars
17.GP 3 XP.004 XP.005 XP.006
17.LL 2 XP.001 XP.002
17.P 4 001 002 003 004
17.RE 27 XP.001 XP.002 XP.003 XP.004 XP.005 XP.006 XP.007 XP.008 XP.009 XP.010 XP.011 XP.012 XP.013 XP.014 XP.015 XP.016 XP.017 XP.018 XP.019 XP.020 XP.021 XP.022 XP.023 XP.024 XP.025 XP.026 XP.027
17.RQ 1 004
17.RTE 3 XP.004 XP.005 XP.006
Chapter 18: The Outer Solar System
18.AT 4 001 002 003 004
18.GP 7 XP.001 XP.002 XP.003 XP.004 XP.005 XP.006 XP.007
18.LL 3 XP.001 XP.002 XP.003
18.P 5 001 002 004 005 006
18.RE 43 XP.001 XP.002 XP.003 XP.004 XP.005 XP.006 XP.007 XP.008 XP.009 XP.010 XP.011 XP.012 XP.013 XP.014 XP.015 XP.016 XP.017 XP.018 XP.019 XP.020 XP.021 XP.022 XP.023 XP.024 XP.025 XP.026 XP.027 XP.028 XP.029 XP.030 XP.031 XP.032 XP.033 XP.034 XP.035 XP.036 XP.037 XP.038 XP.039 XP.040 XP.041 XP.042 XP.043
18.RTE 4 XP.001 XP.002 XP.003 XP.004
Chapter 19: Meteoroids, Meteors, and Meteorites
19.AT 2 001 002
19.GP 4 XP.001 XP.002 XP.003 XP.004
19.LL 3 XP.001 XP.002 XP.003
19.P 8 001 002 003 004 005 007 008 010
19.RE 24 XP.001 XP.002 XP.003 XP.004 XP.005 XP.006 XP.007 XP.008 XP.009 XP.010 XP.011 XP.012 XP.013 XP.014 XP.015 XP.016 XP.017 XP.018 XP.019 XP.020 XP.021 XP.022 XP.023 XP.024
19.RQ 1 012
19.RTE 2 XP.001 XP.002
Chapter 20: Astrobiology: Life on Other Worlds
20.AT 2 001 002
20.GP 3 XP.001 XP.002 XP.003
20.LL 1 XP.002
20.P 8 001 002 003 004 005 006 007 008
20.RE 25 XP.001 XP.002 XP.003 XP.004 XP.005 XP.006 XP.007 XP.008 XP.009 XP.010 XP.011 XP.012 XP.013 XP.014 XP.015 XP.016 XP.017 XP.018 XP.019 XP.020 XP.021 XP.022 XP.023 XP.024 XP.025
20.RQ 14 001 002 003 004 005 006 007 008 009 010 011 012 013 014
20.RTE 2 XP.001 XP.002
Total 1093