BDO of the Day: Rama
Today’s former Big Dumb Object (BDO), the McKendree cylinder, has been postponed until tomorrow in favor of Rama. Rama also requires an explanation of a smaller object, the O'Neill colony or cylinder, so I’ll start there:
In 1974, Gerald O'Neill published a design for a space habitat that could be built with materials from the Moon or asteroids and would contain an Earth-like biosphere. The cylinders would be 16 miles long and 4 miles in diameter (200 square miles of surface area each), large enough to spin for gravity without ill effects for most people. Two cylinders would be paired for attitude control, pointing at the sun. The surface area would be divided equally between stripes of land and of window running lengthwise (3 of each in his original design), meaning that there would only be 100 square miles of land inside. The windows would admit indirect sunlight via mirrors and also allow heat to radiate by looking directly on space. His design incorporates steel structure and cables, though he thought better metals might be available.
Rendezvous With Rama (1973) by Arthur C. Clarke features a single cylinder about double the size of an O'Neill cylinder (and disproportionately fatter), which spins for gravity. Rama, however, is an interstellar craft with a drive system and no windows, though the layout of its artificial lighting strips is similar to O'Neill’s plan. Despite the similarities, Clarke is believed to have come up with the idea independently.
Although small in scale by BDO standards at only 31 miles long and 10 across (not quite a thousand square miles of land—smaller than Rhode Island), Rama is a classic BDO in that the humans exploring it are struck dumb by its proportions and lack of apparent purpose. Rama seems uninhabited despite its city-like structures; the promising discoveries the explorers make don’t help them much. All is eventually made clear in the three sequels, but they weren’t written by Clarke himself and their focus on contemporary issues may date them compared to the first book. YMMV.
Sadly, that Rendezvous With Rama movie I was hoping for never happened.
Update (4/25/2018)
Isaac Arthur devoted an entire video this week to O'Neill cylinders.