The brightness of stars as they appear from Earth is measured by _______ magnitude. A. apparent B. relative C. light D. absolute 2. The idea that the universe is expanding was discovered in the late 1920s by A. Hertzsprung. B. Hubble. C. Doppler. D. Russell. 3. Which one of the following groups is in the proper order from smallest to largest? A. Mars, Jupiter, Pluto B. Saturn, Mercury, Earth C. Pluto, Jupiter, Moon D. Venus, Neptune, Saturn 4. An icy object moving through space in a highly eccentric orbit is called a A. meteorite. B. comet. C. meteor. D. meteoroid. 5. What type of telescope detects energy that's outside the visible spectrum? A. Refracting telescope B. Radio telescope C. Spectroscope D. Reflecting telescope 6. The fact that the position of the constellations seems to change throughout the year is evidence that A. the sun is rotating. B. Earth is rotating. C. Earth is revolving. D. the sun is revolving. 7. According to the three laws of planetary motion, planetary orbits are in the shape of a/an A. arc. B. ellipse. C. circle. D. rectangle. 8. What scientist first proposed that the sun is the center of the solar system? A. Kepler B. Brahe C. Ptolemy D. Copernicus 9. Which one of the following planets does not have rings surrounding it? A. Uranus B. Mars C. Jupiter D. Saturn 10. Which one of the following planets would you expect to have a rocky crust and a dense core? A. Venus B. Neptune C. Saturn D. Jupiter 11. Compared to Earth, Jupiter A. is much smaller. B. rotates more quickly. C. has a lower internal pressure. D. has no moon. 12. Regarding movement of planets, the three laws of planetary motion include all except which of the following? A. The farther a planet is from the sun, the longer it takes to orbit the sun. B. The distance between each planet and the sun is constant. C. When a planet is closer to the sun it moves faster than when it is farther away. D. Orbits are elliptical. 13. What two characteristics of a star are plotted on the Hertzsprung-Russell diagram? A. Rotation and age B. Brightness and age C. Brightness and temperature D. Rotation and temperature 14. An icy piece of rock or rock fragment moving through space is known as a A. meteor. B. meteorite. C. meteoroid. D. comet. 15. We see only one side of the moon from Earth because A. the other side of the moon isn't illuminated when it faces Earth. B. Earth's gravity holds the moon in place so it can't rotate. C. the moon rotates on its axis at the same rate at which it orbits Earth. D. tilt of Earth on its axis causes it to face the same side of the moon. 16. As the moon moves around Earth, a person on Earth doesn't always see the fully lit side of the moon. This phenomenon causes A. eclipses of the moon. B. phases of the moon. C. an increase in perigee. D. an increase in apogee. 17. The use of convex lenses to form an image is the method by which _______ telescopes work. A. refracting B. mirror C. reflecting D. optical 18. The asteroid belt is located betwee.