Ch 15, Chapter Review

Q17. Compare dark matter with dark energy.

A17. dark matter gives off no light but has gravity and can be detected indirectly and dark energy seems to be accelerating the expanding of the universe

Q19. Concept Mapping. Use the following terms to create a concept map: main-sequence star, nebula, red giant, white dwarf, neutron star, and black hole.

A19. nebula main-sequence stars red giant white dwarf neutron stars black hole

Q2. Correct each statement by replacing the capitalized term. ABSOLUTE MAGNITUDE is the brightness of a star as seen from Earth.

A2. apparent magnitude

Q20. You are looking at a star through a telescope in January. There is a small shift in the star's apparent position compared to when you looked at the same star through a telescope in July. What can you conclude about the distance of the star from Earth?

A20. that that star is close to earth but a little distance away

Q21. Explain the differences between main-sequence stars, giant stars, and white dwarfs.

A21. giant stars are at the top of the h-r diagram main sequence stars are in the middle and white dwarfs are at the bottom

Q22. While looking through a telescope, you see a galaxy that doesn't appear to contain any blue stars. What kind of galaxy is the galaxy most likely to be? Explain your answer.

A22. an elliptical galaxy is the most likley kind of galaxy you found

Q23. According to the big bang theory, how did the universe begin?

A23. with a massive explosion that started as a small volume tightly compressed that rapidly expanded and cooled (exploded)

Q24. Using the graph in book... Which star would live longer: a star that has half the mass of the sun or a star that has 2 times the mass of the sun? Explain your answer.

A24. a star that is half the size of the sun would last longer acording to the graph

Q25. Using the graph in book... Approximately how long would a main-sequence star that has a mass of about 1.5 times the mass of the sun live?

A25. about 3-4 billion years

Q26. Using the graph in book... If a galaxy is moving away from Earth at 15,000 km/s, how far from Earth is the galaxy?

A26. it would be 90 light years away according to the graph

Q27. Using the graph in book... If a galaxy is 60 million light-years from Earth, how fast is it moving away from Earth?

A27. it is moving about 11000 km/s

Q28. One star has a magnitude of -5, and another star has a magnitude of +15. How much brighter than the star that has the magnitude of +15 is the star that has the magnitude of -5?

A28. the star that is +15 is much dimmer than the star that is -5

Q3. Correct each statement by replacing the capitalized term. The distance that light travels in space in 1 year is call PARALLAX.

A3. light year

Q5. Which of the following stars has the highest surface temperature? a) red star, b) blue star, c) yellow star, d) orange star

A5. b blue star

Q6. Approximately how many kilometers does a light-year equal? a) 9.46 trillion, b)9.46 million, c) 9.46 quadrillion, d) 9.46 billion

A6. a 9.46 trillion

Q7. The sun is just one of many stars in the Milky Way. Which type of star is the sun? a) a neutron star, b) white dwarf, c) main-sequence star, d) red giant

A7. c main sequence star

Q8. The Milky Way is an example of a(n) a) elliptical galaxy, b) lenticular galaxy, c) irregular galaxy, d) spiral galaxy

A8. d spiral galaxy

Q9. Which of the following contain billions of stars and may have different shapes? a) open clusters, b) galaxies, c) nebulas, d) globular clusters

A9. b galaxies

Q4. Correct each statement by replacing the capitalized term. The MAIN SEQUENCE is a graph that shows the relationship between the surface temperature and absolute magnitude of a star.

Q4. hr diagram

Q1. Which of the following words is the closest in meaning to the word STRUCTURE? a) outline, b) surface, c) arrangement, d) shape

A1. a outline

Q10. Describe how scientists classify stars.

A10. scientists classify stars by their brightness (absolute magnitude), what type of star they are, what color they are, and how hot they are

Q11. Explain why astronomers use light-years to estimate the distance between Earth and stars.

A11. because the distance is too great to be measured in miles, meters, etc

Q12. List the stages in the life cycle of a star in the order in which they happen.

A12. the stages of a star are protostars, main-sequence stars, giants and supergiants, and then the white dwarf

Q13. Explain the role of nuclear fusion in the life cycle of a star.

A13. nuclear fusion affects the life of a star because it is a large energy source that can last for millions of years

Q14. Compare spiral galaxies, elliptical galaxies, and irregular galaxies.

A14. spiral galaxies in a spiral shape elliptical galaxies are like balls of stars irregular galaxies have no definte shape

Q15. Describe the Milky Way, including the sun's position in the Milky Way.

A15. the milky way is a spiral galaxy and the sun is two thirds of the way between the center of the galaxy and the edge

Q16. Explain how the presence of cosmic background radiation supports the big bang theory.

A16. cosmic background radiation supports the big bang theory because when the big bang should have happened then a noise was evenly distributed throughout the universe and is still being distributed