Moon

A planetoid located about 256,000 miles away, the moon is the only known natural satellite of the Earth.

In February 1950, Lex Luthor fuses “a couple of handfuls of dust from the dark side of the moon” with several other “strange materials” in order to produce the first known sample of synthetic Kryptonite (Act No. 141: “Luthor’s Secret Weapon”).

In September-October 1950, when Superman believes he is dying of kryptonite poisoning, he engraves a gigantic message on the surface of the moon in hopes of bequeathing mankind a farewell “guiding principle.”“Do good unto others,” reads the message in mile-high letters, “and every man can be a Superman! [signed Superman (Clark Kent)].” A short while later, however, after having learned that he is not dying after all, Superman returns to the moon and erases the name “Clark Kent” from his message just as the moon is about to appear from behind a cloud and expose his secret identity to the entire world (S No. 66/2: “The Last Days of Superman!”). In another telling, when Superman believes he is dying of exposure to Virus-X, he uses his heat vision to inscribe this message -- later Krypto and Supergirl use their vision to erase it (S No. 156, Oct 1962: "The Last Days of Superman!").

In January-February 1953, when Professor Wilson divides the formula for his “four-dimensional projector” into seven parts and hides them in seven inaccessible places, one of the hiding places he chooses is the moon’s largest crater (WF No. 62: “The Seven Secrets of Superman”).