The Adventures of Superman (radio) home planet of Krypton is located on the far side of the sun, as opposed to a distant star system as it is in most stories. During the journey to Earth, baby Kal-el grows into an adult and emerges fully grown from his ship after it lands on Earth. He is never adopted by the Kents but immediately begins his superhero career. This was eventually retconned in later episodes to match the narrative of the comic books. This serial introduced the fictional mineral kryptonite, the radiation from which can weaken and even (in some continuities) kill Superman. Aside from giving
Mongo (fictional planet) the air, which caused acid rain, killed wildlife, and contaminated Mongo's water. The planet became uninhabitable. A small portion of Mongo's people emigrated to Arkaylia. After three generations on the artificial moon, Mongo's environment partially repaired itself. As a result, the people returned to the planet. Clean water, known as "source water", still remained scarce and came from underground. Centuries later, Ming seized power and began his rule. The 1977 Fantasy Games Unlimited role-playing game "Flash Gordon & the Warriors of Mongo" used the planet Mongo as its setting. The game was designed by science fiction writer Lin Carter and