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Universe Eighth Edition PowerPoint Presentation
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Universe Eighth Edition

Universe Eighth Edition

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Universe Eighth Edition

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  1. Roger A. Freedman • William J. Kaufmann III Universe Eighth Edition CHAPTER 24 Galaxies

  2. Chapter 24 and 26 online quizzes due Thursday 12/9 Skip Chapter 27 Final Exam – Monday 12/13, 5:30-7:30 PM The final will cover chapters 23, 24 and 26 only, same format as Exams 1-3 Last HW!

  3. How did Edwin Hubble show that M31 in Andromeda is a distant galaxy and not part of the Milky Way? • By measuring the distance to M31using Cepheid variables. • By measuring the distance to M31using RR Lyrae variables. • By precisely measuring the parallax of M31. • By observing a nova in M31. • By observing a supernova in M31. Q24.7

  4. How did Edwin Hubble show that M31 in Andromeda is a distant galaxy and not part of the Milky Way? • By measuring the distance to M31using Cepheid variables. • By measuring the distance to M31using RR Lyrae variables. • By precisely measuring the parallax of M31. • By observing a nova in M31. • By observing a supernova in M31. A24.7

  5. Which of the following best describes the Hubble law in its simplest form? • The recessional velocity of a galaxy is proportional to its distance from us. • The recessional velocity of a galaxy is inversely proportional to its distance from us. • The brightness of a galaxy is proportional to its distance from us. • The brightness of a galaxy is inversely proportional to its distance from us. • The brightness of a galaxy is inversely proportional to its color. Q24.10

  6. Which of the following best describes the Hubble law in its simplest form? • The recessional velocity of a galaxy is proportional to its distance from us. • The recessional velocity of a galaxy is inversely proportional to its distance from us. • The brightness of a galaxy is proportional to its distance from us. • The brightness of a galaxy is inversely proportional to its distance from us. • The brightness of a galaxy is inversely proportional to its color. A24.10

  7. In which of the following types of galaxies would you be least likely to find a newly-formed star? • Elliptical • Spiral • Irregular • Misleading question — newly-formed stars can be found in ellipticals, spirals, and irregulars Q24.8

  8. In which of the following types of galaxies would you be least likely to find a newly-formed star? • Elliptical • Spiral • Irregular • Misleading question — newly-formed stars can be found in ellipticals, spirals, and irregulars A24.8

  9. Key Ideas • The Hubble Classification: Galaxies can be grouped into four major categories: spirals, barred spirals, ellipticals, and irregulars. • The disks of spiral and barred spiral galaxies are sites of active star formation. • Elliptical galaxies are nearly devoid of interstellar gas and dust, and so star formation is severely inhibited. • Lenticular galaxies are intermediate between spiral and elliptical galaxies. • Irregular galaxies have ill-defined, asymmetrical shapes. They are often found associated with other galaxies.