1. universe   pianeta   terra   sole   universo   Hint Half-n-half Clue   2. light years   orbita   atmosfera   anni chiari   terra   Half-n-half Clue   3. astronomer   orbita   Spazio cosmico   stella   astronomo   Half-n-half Clue   4. meteor   meteora   terra   sistema solare   asteroid   Half-n-half Clue   5. atmosphere   cometa   satellite   Spazio cosmico   atmosfera   Half-n-half Clue   6. comet   universo   asteroid   atmosfera   cometa   Half-n-half Clue   7. Earth   Spazio cosmico   luna   astronomo   terra   Half-n-half Clue