Astronomy Exam 2 Part 4

10 Questions | Total Attempts: 108

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Astronomy Quizzes & Trivia

Astronomy exam part 4. Taken from astron. 100 exam 2.


Questions and Answers
  • 1. 
    We see distant objects as they appeared in the distant past because
    • A. 

      A. the universe is expanding.

    • B. 

      B. the fabric of space is curved by the presence of mass.

    • C. 

      C. all galaxies see themselves at the center of universal expansion.

    • D. 

      D. light travels at a finite velocity and takes time to get to us.

    • E. 

      E. the universe had a distinct beginning about 15 billion years ago.

  • 2. 
    Astronomers use Cepheid variable stars to measure galaxies’ distances because
    • A. 

      A. the faster they vary, the more distant they are.

    • B. 

      B. their luminosity can be determined from their period of variation.

    • C. 

      C. they obey Hubble’s law.

    • D. 

      D. they are the most common type of main-sequence star visible in galaxies.

    • E. 

      E. they all lie in the same spot on the HR diagram.

  • 3. 
    Whether the universe is open, closed or flat depends on the
    • A. 

      A. luminosity

    • B. 

      B. temperature

    • C. 

      C. radius

    • D. 

      D. rotation rate

    • E. 

      E. density

  • 4. 
    Spiral galaxies are known to rotate by measuring
    • A. 

      A. the Doppler shifts of stars on each side of its center.

    • B. 

      B. the relative motions of other galaxies inside them.

    • C. 

      C. the length and curvature of their spiral arms.

    • D. 

      D. the time it takes individual stars to orbit the center.

    • E. 

      E. None of the above—galaxies don’t rotate.

  • 5. 
    An astronomer now living in another galaxy far away from ours would see
    • A. 

      A. some of the most distant galaxies coming toward her and some going away from her.

    • B. 

      B. many more nearby quasars than we do.

    • C. 

      C. our Galaxy approaching her.

    • D. 

      D. the more-or-less same relation between redshift and distance that we see.

    • E. 

      E. All of the above.

  • 6. 
    Edwin Hubble recognized that the Andromeda nebula was a separate ”island universe” rather than a component of our own galaxy because
    • A. 

      A. he observed that the nebula was rotating.

    • B. 

      B. he used Cepheid variables to find it was a tremendous distance away.

    • C. 

      C. he determined that the nebula was moving away from our Galaxy.

    • D. 

      D. he counted that there were more than one billion stars in the nebula.

    • E. 

      E. he detected dust and gas in the nebula.

  • 7. 
     Most of the helium in the Universe is believed to be produced in
    • A. 

      A. red giants.

    • B. 

      B. main-sequence stars.

    • C. 

      C. planetary nebulae.

    • D. 

      D. the Big Bang.

    • E. 

      E. supernovae.

  • 8. 
    Based on the rotation curves of stars in spiral galaxies and the Milky Way, most of the mass in galaxies is believed to be in the form of
    • A. 

      A. dark matter.

    • B. 

      B. neutral hydrogen.

    • C. 

      C. luminous stars.

    • D. 

      D. ionized hydrogen.

    • E. 

      E. black holes.

  • 9. 
    What is meant by dark matter?
    • A. 

      A. Mass that disappears into black holes.

    • B. 

      B. Mass made of anti-matter whose effect cancels out the gravity of ordinary matter.

    • C. 

      C. Mass that radiates strongly at X-ray wavelengths and is therefore invisible with ordinary light.

    • D. 

      D. Mass deduced to be present from its gravitational effect but which emits no visible light or other detectable radiation

    • E. 

      E. None of the above.

  • 10. 
     Hubble’s law
    • A. 

      A. tells us that the universe is expanding.

    • B. 

      B. permits us to measure the distances to distant galaxies and quasars.

    • C. 

      C. implies that the universe had a beginning about 15 billion years ago.

    • D. 

      D. says that more distant galaxies recede more rapidly than nearby ones.

    • E. 

      E. all of the above.

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