Name______Period______
Chapter 26 Book Questions
Energy from the Sun (pages 828–829)
1. The sun gives off a large amount of energy in the form of ______radiation.
2. Circle the letter of each sentence that is true about nuclear fusion inthe sun.
A. Less massive nuclei combine into more massive nuclei.
B. The end product of fusion is hydrogen.
C. Fusion is a type of chemical reaction.
D. Hydrogen nuclei fuse into helium nuclei.
Forces in Balance (page 829)
3. For the sun to be stable, inward and outward forces within it must be in ______.
4. True or false? The sun remains stable because the inward pull of gravity balances the outward push of thermal pressure from nuclear fission. ______
Properties of Stars (pages 836–837)
5. Circle the letter of each property that astronomers use to classify stars.
A. brightness B. distance
C. color D. size
6. True or false? The brightness of a star as it appears from Earth is called its absolute brightness. ______
7. A star’s ______can be used to identify different elements in the star.
The Hertzprung-Russell Diagram (pages 838–839)
8. Circle the letter of each way that Hertzprung-Russell (H-R) diagrams might be used.
A. to study sizes of starsB. to study distant planets
C. to determine a star’s absolute brightnessD. to determine a star’s surface temperature or color
9. Circle the letter of each sentence that is true about supergiants.
A. They are found at the upper right of the H-R diagram.
B. They are much brighter than main sequence stars of the same temperature.
C. They are 100 to 1000 times the diameter of the sun.
D. They are smaller and fainter than giants.
10. How does the brightness of white dwarfs compare to the brightness of main sequence stars?
______
11. Provide labels for each of the letters shown on the H-R diagram to the right.
A. ______
B. ______
C. ______
D. ______
How Stars Form (pages 840–841)
12. A large cloud of dust and gas spread out over a large volume of space is called a(n)______.
13. Describe how a star is formed. ______
______
Adult Stars (page 841)
14. A star’s ______determines the star’s place on the main sequence and how long it will stay there.
15. Circle the letter of each true sentence about adult main-sequence stars.
A. High-mass stars become the bluest and brightest main-sequence stars.
B. Low-mass stars are usually short-lived.
C. Yellow stars like the sun are in the middle of the main sequence.
D. Red stars are the hottest and brightest of all visible stars.
The Death of a Star (pages 842–844)
16. The core of a star starts to shrink when the core begins to run out of______.
17. Name three possible end stages of a star.
A.______B.______C.______
18. Is the following sentence true or false? The final stages of a star’s life depend on its mass.______
19. Circle the letter of each sentence that is true about the death of low-mass and medium-mass stars.
A. The dying stars are called planetary nebulas.
B. They remain in the giant stage until their supplies of helium and hydrogen are gone and there are no other elements to fuse.
C. The energy coming from the stars’ interiors decreases and the stars eventually collapse.
D. The cores of the stars shrink and only their atmospheres remain.
20. List the names of the stages in the evolution of a low-mass star shown in the diagram below.
A. ______B. ______C. ______
D. ______E. ______F. ______
21. True or false? A high-mass star dies quickly because it consumes fuel rapidly. ______
Hubble’s Law (pages 852–853)
22. True or false? The apparent change in frequency and wavelength of a wave as it moves towards or away from an observer is known as the Doppler effect. ______
23. How can astronomers use the Doppler effect? ______
______
24. Circle the letter of each sentence that is true about spectrums of stars or galaxies.
A. As a star or galaxy circles the Earth, the lines in its spectrum shift toward the middle of the spectrum.
B. As a star moves toward Earth, the lines in its spectrum are shifted toward shorter wavelengths.
C. As a star or galaxy moves away from Earth, the lines in its spectrum are shifted toward longer wavelengths.
D. The greater the observed shift in spectrum, the greater the speed the star or galaxy is moving.
25. The shift in the light of a galaxy toward the red wavelengths is called a(n) ______.
26. Describe Hubble’s Law. ______
______
27.True or false? The most distant galaxies that can be seen from Earth are moving away at more than 90% of the speed of light. ______
28. Describe what the observed red shift in the spectra of galaxies shows.______
______
The Big Bang Theory (page 854)
29. Astronomers theorize that the universe came into being in an event called the ______.
30. Circle the letter of each sentence that is true according to the big bang theory.
A. The matter and energy in the universe was once concentrated in a very hot region smaller than a sentence period.
B. The universe began billions of years ago with an enormous explosion.
C. The universe came into existence in an instant.
D. The matter and energy in the universe has taken billions of years to form.
31. After the big bang, it is theorized that the universe ______.
32. How large was the universe when the sun and solar system formed?
33. Circle the letter of each sentence that gives evidence that supports the big bang theory.
A. The existence of cosmic microwave background radiation.
B. The red shift in the spectra of distant galaxies.
C. The fact that the sun is about 20 billion years old.
D. The pulling of atoms together into gas clouds by gravity.
34. Recent measurements of the microwave background radiation have led astronomers to estimate that the universe is ______.
Continued Expansion (page 855)
35. Matter that does not give off radiation is known as ______.
36. Circle the letter of each sentence that is true about dark matter.
A. Astronomers currently don’t know what it is or how it is distributed.
B. It cannot be seen directly.
C. It can be measured using the Doppler effect.
D. It can be detected by observing how its gravity affects visible matter.
37. Why is it significant that the galaxies contain as much as ten times more dark matter than visible matter? ______
______
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