1. 彗星   atmosphere   meteorite   comet   asteroid   Hint Half-n-half Clue   2. 地球   meteorite   gravity   Earth   galaxy   Half-n-half Clue   3. 星   outer space   Earth   star   astronomer   Half-n-half Clue   4. 星系   moon   galaxy   meteorite   satellite   Half-n-half Clue   5. 太阳   Sun   solar system   light years   satellite   Half-n-half Clue   6. 望远镜   light years   telescope   universe   Sun   Half-n-half Clue   7. 宇航员   astronomer   planet   astronaut   atmosphere   Half-n-half Clue