Close your eyes and drift across the solar system, visiting the silent worlds that orbit our planets. From the volcanic fires of Io to the icy oceans of Europa, each moon is a world unto itself. Ganymede, the largest moon, surpasses the planet Mercury in size, while Titan boasts a thick atmosphere and surface lakes of methane and ethane [citation:7]. Enceladus blasts water into space, hinting at a subsurface ocean [citation:9]. Earth's Moon, our silent guardian, keeps our axis stable and creates the ocean's tides. Let these gentle facts about our cosmic neighbors carry you into deep, restful sleep.