Rama

Rama is a mysterious extraterrestrial vessel that is the subject and setting of the science fiction novel Rendezvous with Rama by Arthur C. Clarke, and the later sequel trilogy by Clarke and Gentry Lee: Rama II, Garden of Rama, and Rama Revealed. It exists in a fictional future timeline of our own world. Rama is essentially a dark, featureless metallic cylinder, but is distinguished by its size: 50 km long and 20 km in diameter. Although it qualifies as a vessel, carrying an advanced propulsion system capable of interstellar travel, it is better described as a mobile "worldlet." The cylinder is mostly hollow; Rama's rotation around its long axis creates the illusion of gravity on the inner surface of the shell, in the style of an O'Neill cylinder, however the Coriolis effect produces odd effects when objects are not in contact with the hull. Rama is, for all intents and purposes, an artificial world, with a usable landscape, capable of supporting life. Rama was first encountered by... full article at wikipedia