This is an animation depicting the interior of a type of large-scale space colony called an O'Neill Cylinder, made popular by American Physicist Gerard K. O'Neill in his book The High Frontier: Human Colonies in Space (1976). The interpretation in this view differs from O'Neill's original idea, in which the inner surface had transparent strips running its length, and mirrors outside those sections to bounce sunlight inside. Instead, here the surface is fully landscaped, with a light source provided by a central, axial light strip powered by nuclear fusion (or other future technology). The cylinder here measures 9.2km (5.6 miles) in diameter and 36km (20 miles) long. Rotation about the long axis, at a rate of 210 m/s at the surface (2.3 minutes per rotation), provides artificial 1g of artificial gravity by means of centripetal force.