In the ancient times, before mankind mastered the force of gravity, humans sometimes lived in gigantic, cylindrical space stations. These cylinders were several kilometres long and slowly rotated around their own axis, so that the centrifugal force on the inside was equal to the gravity on Terra.
It is likely that these 'ohnyl cylinders' were the conventional sub-light spacecraft used to colonise nearby star systems during the Dark Age of Technology. Generations of people would live and die onboard the ships, while they crossed the gulf between the stars. When the Warp Drive and the Geller Field was invented, such vessels were of course rendered obsolete.[Needs Citation]