Is contemplating the universe, stars, and moon permissible in Islamic law, and is there a fear that one who does so might become a worshipper of planets?

Allah commanded His servants to ponder the universe in order to recognize His greatness and His Oneness, as He says: "Have they not looked into the realm of the heavens and the earth and whatever God has created?" This pondering should be a means of increasing faith and knowing the Creator; otherwise, mere empty observation is not praiseworthy. Indeed, Allah condemned those whose knowledge was limited to outward appearances and who were heedless of their meanings. As for the fear of worshipping planets, it is a baseless whisper (waswasa), and one should firmly affirm that you worship Allah alone, the Creator of the planets.