1. 地球   Earth   astronaut   solar system   orbit   Hint Half-n-half Clue   2. 太陽   solar system   atmosphere   comet   Sun   Half-n-half Clue   3. 望遠鏡   Sun   telescope   universe   asteroid   Half-n-half Clue   4. 銀河系   atmosphere   meteor   astronomer   galaxy   Half-n-half Clue   5. 光年   galaxy   Sun   comet   light years   Half-n-half Clue   6. 重力   telescope   gravity   planet   meteorite   Half-n-half Clue   7. 流星   asteroid   Sun   meteor   meteorite   Half-n-half Clue