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Astronomy Chapter Twelve

21 Questions
Astronomy Quizzes & Trivia
Questions and Answers
  • 1. 
    What did Carl Sagan mean when he said that we are all "star stuff"?
    • A. 

      That life would be impossible without energy from the Sun

    • B. 

      That Earth formed at the same time as the Sun

    • C. 

      That the carbon, oxygen, and many elements essential to life were created by nucleosynthesis in stellar cores

    • D. 

      That the Sun formed from the interstellar medium: the "stuff" between the stars

    • E. 

      That the Universe contains billions of stars

  • 2. 
    Which two energy sources can help a star maintain its internal thermal pressure?
    • A. 

      Nuclear fusion and gravitational contraction

    • B. 

      Nuclear fission and gravitational contraction

    • C. 

      Nuclear fusion and nuclear fission

    • D. 

      Chemical reactions and gravitational contraction

    • E. 

      Nuclear fusion and chemical reactions

  • 3. 
    What type of star is our Sun?
    • A. 

      Low-mass star

    • B. 

      Intermediate-mass star

    • C. 

      High-mass star

  • 4. 
    What is the range of star masses for high-mass stars?
    • A. 

      Between 500 and 1,000 solar masses

    • B. 

      Between 150 and 500 solar masses

    • C. 

      Between 10 and 150 solar masses

    • D. 

      Between 2 and 100 solar masses

    • E. 

      Between 2 and 50 solar masses

  • 5. 
    No stars are expected with masses greater than 150 times our Sun because
    • A. 

      Molecular clouds do not have enough material to form such massive stars.

    • B. 

      They would fragment into binary stars because of their rapid rotation.

    • C. 

      They would generate so much power that they would blow themselves apart.

    • D. 

      They shine exclusively at X-ray wavelengths and become difficult to detect.

    • E. 

      They are not bright enough to be seen nearby.

  • 6. 
    Which of the following statements about degeneracy pressure is not true?
    • A. 

      Degeneracy pressure varies with the temperature of the star.

    • B. 

      Degeneracy pressure can halt gravitational contraction of a star even when no fusion is occurring in the core.

    • C. 

      Degeneracy pressure keeps any protostar less than 0.08 solar mass from becoming a true, hydrogen-fusing star.

    • D. 

      Degeneracy pressure arises out of the ideas of quantum mechanics.

  • 7. 
    What is the fate of an isolated brown dwarf?
    • A. 

      It will become a white dwarf.

    • B. 

      It will become a neutron star.

    • C. 

      It will become a black hole.

    • D. 

      It will slowly evaporate to nothing.

    • E. 

      It will remain a brown dwarf forever.

  • 8. 
    What happens when a star exhausts its core hydrogen supply?
    • A. 

      Its core contracts, but its outer layers expand and the star becomes bigger and brighter.

    • B. 

      It contracts, becoming smaller and dimmer.

    • C. 

      It contracts, becoming hotter and brighter.

    • D. 

      It expands, becoming bigger but dimmer.

    • E. 

      Its core contracts, but its outer layers expand and the star becomes bigger but cooler and therefore remains at the same brightness.

  • 9. 
    Why does a star grow larger after it exhausts its core hydrogen?
    • A. 

      The outer layers of the star are no longer gravitationally attracted to the core.

    • B. 

      Hydrogen fusion in a shell outside the core generates enough thermal pressure to push the upper layers outward.

    • C. 

      Helium fusion in the core generates enough thermal pressure to push the upper layers outward.

    • D. 

      Helium fusion in a shell outside the core generates enough thermal pressure to push the upper layers outward.

    • E. 

      The internal radiation generated by the hydrogen fusion in the core has heated the outer layers enough that they can expand after the star is no longer fusing hydrogen.

  • 10. 
    How many helium nuclei fuse together when making carbon?
    • A. 

      2

    • B. 

      3

    • C. 

      4

    • D. 

      Varies depending on the reaction

    • E. 

      None of the above

  • 11. 
    The helium fusion process results in the production of
    • A. 

      Hydrogen.

    • B. 

      Oxygen.

    • C. 

      Carbon.

    • D. 

      Nitrogen.

    • E. 

      Iron.

  • 12. 
    What happens after a helium flash?
    • A. 

      The core quickly heats up and expands.

    • B. 

      The star breaks apart in a violent explosion.

    • C. 

      The core suddenly contracts.

    • D. 

      The core stops fusing helium.

    • E. 

      The star starts to fuse helium in a shell outside the core.

  • 13. 
    What is a planetary nebula?
    • A. 

      A disk of gas surrounding a protostar that may form into planets

    • B. 

      What is left of the planets around a star after a low-mass star has ended its life

    • C. 

      The expanding shell of gas that is no longer gravitationally held to the remnant of a low-mass star

    • D. 

      The molecular cloud from which protostars form

    • E. 

      The expanding shell of gas that is left when a white dwarf explodes as a supernova

  • 14. 
    What happens to the core of a star after a planetary nebula occurs?
    • A. 

      It contracts from a protostar to a main-sequence star.

    • B. 

      It breaks apart in a violent explosion.

    • C. 

      It becomes a white dwarf.

    • D. 

      It becomes a neutron star.

    • E. 

      None of the above

  • 15. 
    Which of the following sequences correctly describes the stages of life for a low-mass star?
    • A. 

      Red giant, protostar, main-sequence, white dwarf

    • B. 

      White dwarf, main-sequence, red giant, protostar

    • C. 

      Protostar, red giant, main-sequence, white dwarf

    • D. 

      Protostar, main-sequence, white dwarf, red giant

    • E. 

      Protostar, main-sequence, red giant, white dwarf

  • 16. 
    What is the CNO cycle?
    • A. 

      The process by which helium is fused into carbon, nitrogen, and oxygen

    • B. 

      The process by which carbon is fused into nitrogen and oxygen

    • C. 

      A type of hydrogen fusion that uses carbon, nitrogen, and oxygen atoms as catalysts

    • D. 

      The period of a massive star's life when carbon, nitrogen, and oxygen are fusing in different shells outside the core

    • E. 

      The period of a low-mass star's life when it can no longer fuse carbon, nitrogen, and oxygen in its core

  • 17. 
    What happens when the gravity of a massive star is able to overcome neutron degeneracy pressure?
    • A. 

      The core contracts and becomes a white dwarf.

    • B. 

      The core contracts and becomes a ball of neutrons.

    • C. 

      The core contracts and becomes a black hole.

    • D. 

      The star explodes violently, leaving nothing behind.

    • E. 

      Gravity is not able to overcome neutron degeneracy pressure.

  • 18. 
    What types of stars end their lives with supernovae?
    • A. 

      All stars that are red in color

    • B. 

      All stars that are yellow in color

    • C. 

      Stars that are at least several times the mass of the Sun

    • D. 

      Stars that are similar in mass to the Sun

    • E. 

      Stars that have reached an age of 10 billion years

  • 19. 
    After a supernova event, what is left behind?
    • A. 

      Always a white dwarf

    • B. 

      Always a neutron star

    • C. 

      Always a black hole

    • D. 

      Either a white dwarf or a neutron star

    • E. 

      Either a neutron star or a black hole

  • 20. 
    Why is Supernova 1987A particularly important to astronomers?
    • A. 

      It occurred only a few dozen light-years from Earth.

    • B. 

      It provided the first evidence that supernovae really occur.

    • C. 

      It provided the first evidence that neutron stars really exist.

    • D. 

      It was the first supernova detected in nearly 400 years.

    • E. 

      It was the nearest supernova detected in nearly 400 years.

  • 21. 
    You discover a binary star system in which one member is a 15Msun main-sequence star and the other star is a 10Msun giant. Why should you be surprised, at least at first?
    • A. 

      It doesn't make sense to find a giant in a binary star system.

    • B. 

      The odds of ever finding two such massive stars in the same binary system are so small as to make it inconceivable that such a system could be discovered.

    • C. 

      The two stars in a binary system should both be at the same point in stellar evolution; that is, they should either both be main-sequence stars or both be giants.

    • D. 

      The two stars should be the same age, so the more massive one should have become a giant first.

    • E. 

      A star with a mass of 15Msun is too big to be a main-sequence star.