Download Chapter 21 Study Guide

Chapter 21 Study Guide
Section 21-1: Tools of Modern Astronomy
Name _______________________Period ____
(pages 714-720)
1. The light you see with your eyes is called _________________________ _______________________.
2. ___________________________________ __________________________ is energy that can travel directly
through space in the form of waves.
3. The distance between the crest of one wave and the crest of the next wave is called a ________________.
4. A range of different wavelengths is called a __________________________.
5. List the colors that form the spectrum of visible light.___________________________________________
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6. The _________________________________________ __________________________ is the range of
wavelengths of electromagnetic waves.
7. Most telescopes collect and focus different types of ___________________________________
___________________________, including visible light.
8. A ___________________________ lens is a piece of transparent glass, curved so that the middle is thicker
than the edges.
9. -11. The three main types of telescopes are _____________________________________,
_______________________________________ and __________________________________________.
12. A building that contains one or more telescopes is called an _____________________________.
13. Name one reason why astronomers have built large telescopes on the tops of mountains.
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14. The Hubble Space Telescope makes images that are much better than images made by telescopes on Earth
because ______________________________________________________________________________.
15. A ___________________________ breaks the light from an object into colors and then photographs the
spectrum.
16. Astronomers use a spectrograph to collect what two major parts of information about stars?
______________________________________________________________________________________
17. T or F ? Each element has a unique set of lines on a spectrum.
18. How can astronomers infer which elements are found in a star?
_________________________________
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19. Stars at different temperatures produce different ___________________ _________________________.
20. How can astronomers infer how hot a star is? _______________________________________________
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Section 21-2: Characteristics of Stars
(pages 723-729)
21. A cluster of stars, gases and dust held together by gravity is called a ________________________.
22. The _____________________________ is all of the space and everything in it.
23.Most of the universe is _______________________ _____________________.
24. T or F ? The light-year is a unit of time.
25. ___________________________ is the apparent change in position of an object when you look at it from
different places.
27. Astronomers use parallax to measure the distance to _________________________ stars only.
28-29. The three main characteristics that astronomers use to classify stars are ____________________,
_________________________________ and _____________________________.
30-34. List the star groups in order from SMALLEST (a.) to LARGEST (e.).
a. ______________________________
d. _____________________________
b. ______________________________
e. _____________________________
c. ______________________________
35. A star's ______________________ reveals it temperature.
36. The amount of light given off by a star is called its ___________________________________.
37-38. How bright a star looks from Earth depends on what 2 factors? _______________________________
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39. A star's ___________________________ magnitude is a star's brightness as seen from Earth.
40. A star's ___________________________ magnitude is a star's brightness as if all the stars were the same
distance away from Earth.
41. The __________________________________________ diagram shows the relationship between the surface
temperature and the brightness of stars.
42. An area on the H-R Diagram that runs from the upper left to the lower right and includes more than 90% of
all stars is called the __________________________ ________________________________.
Section 21-3: Lives of Stars
(pages 732-736)
43. A neutron star that appears to give off pulses of radio waves is called a ___________________________.
44. A large amount of gas and dust spread out in an immense volume is called a _______________________.
45. True or False? All stars begin their lives as part of nebulas.
46. The earliest stage of a star's life is called a ____________________________________.
47-49. A star is born when contracting ______________ and _______________ become so hot that
_________________________ _______________________ begins.
50. A star's ___________________ determines how long a star will live.
51. A __________________ dwarf is the remaining hot core of a red giant after the outer part has drifted away.
52. A ___________________ dwarf is a dead star after a white dwarf has run out of fuel.
53. A ___________________________________ is an explosion of a red giant or supergiant.
54. A tiny star that remains after a supernova is called a _________________________ star.
55. The remains of a massive star that is pulled into a small volume by gravity is called a _____________ hole.
56. A distant galaxy with a black hole at its center is called a ___________________________.
Section 21-4: Star Systems and Galaxies
(pages 737-740)
57.A ___________________ _______________________ is a group of two or more stars.
58. Star systems with two stars are called double stars or ____________________________ stars.
59. Alpha Centauri A and Alpha Centauri B form a ______________________ star with Proxima Centauri.
60. A star system in which one star blocks the light from another star is called an
________________________________ ______________________________.
61. The galaxy in which our solar system is located is called the _______________________ ____________.
62. There are __________________________ of galaxies in the universe.
63-65. The 3 types of galaxies are ____________________________, _______________________________ and
______________________________.
Section 21-5: History of the Universe
(pages 741-744)
66. The theory that there was an initial explosion that resulted in the formation and expansion of the universe is
called the ______________ ____________________ ____________________.
67. Astronomers theorized that the big bang took place ______________________________ years ago.
68. Our solar system was formed about _______________________________ years ago.
69. Theoretically, our solar system was formed when a _______________________ collapsed.
70-71. There are 2 main theories about what will happen to the universe. Explain each.
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