첫 번째: 지구에서 달까지의 거리는 어떻게 구할 수 있을까? ········································7 두 번째: 지구에서 태양까지의 거리는 어떻게 구할 수 있을까? ····································21 세 번째: 금성의 공전궤도는 원인가? ········································································29 [보충 활동] 수성, 화성의 공전궤도 그리기 ·······························································45 네 번째: 지구의 공전궤도는 원인가? ········································································73 다섯 번째: 달의 궤도도 원 궤도인가? ····································································103 여섯 번째: 1년 뒤 행성의 위치를 예측할 수 있는가? ···············································117 일곱 번째: 갈릴레이가 관측했던 목성의 4개의 위성도 그 위치를 예측할 수 있을까? ···139 [보충 활동] 천체 관측: 달, 목성, 토성 관측하기 ·····················································193