New submitter oag2 writes "Discover Magazine has a new slideshow of NASA's pie-in-the-sky (or, rather, toroid-in-the-sky) mock-ups of what space colonies would look like, complete with verdant mountains, flowing rivers, cocktail parties, and a guy on a floating bicycle. Though the designs are retro-futuristic, the artist who made them was prescient in other ways. From the accompanying article: "In the context of the 70s, when we had some sense of momentum from Apollo as far as expanding the human presence in space, it seemed like the kind of thing we could have just picked up and moved with," Davis says. "And it's still possible. It's just a matter of where we decide to spend our money." But Guidice remembers a more telling prophecy from O'Neill. "One of the most memorable things I ever heard him say was, 'If we don't do it right now,' meaning in the next 20 years, and that was 20 years ago, 'then we'll never do it, because we'll be overpopulated and the strain on the natural resources will be the number one priority. We will not have any sort of inclination to see this through."'" The O'Neill referenced above is Gerard K. O'Neill, physicist and founder of the Space Studies Institute. He wrote a book in 1976 called The High Frontier which featured these mock-up paintings, and explained in great detail how the space habitats would function. It's a fascinating book, and well worth reading if the pictures pique your curiosity.