A galaxy is held together by a stellar dust b

17. A galaxy is held together by
a. stellar dust.
b. gravitational attraction.
c. electronic attractions.
d. pulsating stars.
18. The diameter of the Milky Way is about
19. Approximately how old is the universe?
20. Stars twinkle and planets do not twinkle because

c. stars appear as point sources of light, and planets are disk sources.
d. All of the above are correct.
21. How much of the celestial meridian can you see from any given point on the surface of Earth?
a. One-fourth
b. One-half
c. Three-fourths
d. All of it
22. Which of the following coordinate system of lines depends on where you are on the surface of
Earth?
23. The angle that you see Polaris, the North Star, above the horizon is about the same as your
approximate location on
24. If you were at the north celestial pole looking down on Earth, how would it appear to be moving?
(Use a globe if you wish.)
25. Your answer to question 24 means that Earth turns
a. from the west toward the east.

b. from the east toward the west.
c. at the same rate it is moving in its orbit.
d. not at all.
26. Your answer to question 25 means that the Moon, Sun, and stars that are not circumpolar appear to
rise in the
27. How many degrees of arc above the horizon is a star located halfway between directly over your
head and the horizon?
28. In which part of a newborn star does the nuclear fusion take place?
29. Which of the following stars would have the longer life spans?
a. The less massive
b. Between the more massive and the less massive
c. The more massive
d. All have the same life span.