SC100 Class 3 Homework Assignment 1. What did the builders of Stonehenge accomplish? a. They demonstrated that some natural events are predictable. b. They figured out reasons why the Solar System works as it does. c. They established contact with ancient astronauts. d. They maintained written records of natural events. e. They accomplished all of the above.

SC100 Unit 3a Homework Assignment 2. Closely spaced groups of stars that maintain their relative positions in the sky are called a. constellations. b. galaxies. c. meteors. d. comets. e. quarks.

SC100 Unit 3a Homework Assignment 3. The Greek astronomers' explanation for the celestial spheres did not encompass the phenomenon of a. geocentricism. b. planetary motion. c. uniform motion. d. retrograde motion. e. a & c

SC100 Unit 3a Homework Assignment 4 The Ptolemaic theory of the universe includes a. an unmoving Earth at the center. b. an unmoving Sun at the center. c. elliptical orbits. d. stationary planets. e. no explanation about the Sun's movement

SC100 Unit 3a Homework Assignment 5. Copernicus hypothesized that a. the Sun was the center of the universe. b. the Earth was the center of the universe. c. the planetary bodies had circular orbits. d. a & c e. b & c