Larry page, ceo of Google, has said that he gets excited about ideas that can change the world even though “it's easy to think they're crazy now.” Take the company's self-driving cars project. Within 10 years, he told a rapt audience at the 2012 Google Zeitgeist meeting, the technology could eliminate a leading cause of death for 16-year-olds. They would have the illusion of driving, he explained: “They just can't kill themselves or anybody else.” Or consider wearable computers such as Google's prototype Project Glass, which could add information to augment the reality you see: “Every time I use it, I feel like I'm living in the future,” Page said. Soon even your smartphone will know when not to interrupt you or when to warn you if you will be late to a meeting based on an item in your calendar, where you are at that moment and that appointment's physical location.

Page was just looking a few years ahead. How much more crazy—and world-changing—do things become when you look over larger spans of time? In this issue's cover story, you will find out. Riffing off Scientific American's popular monthly column, 50, 100 & 150 Years Ago, we speculate about the future using those same time blocks, ultimately going up to a century and a half ahead. Among other things, you will learn about an airborne successor to those self-driving cars, three scenarios about what a century of climate change could bring and, 150 years from now, the possibility of mental interfaces with computers. Turn to page 26 for the start of the section. A companion feature by Cameron M. Smith, called “Starship Humanity,” discusses our next steps for going beyond Earth as a species and how that could affect our evolution; the story starts on page 38.

In the category of science fiction that is here today, you can explore the feature article “Bionic Connections,” by D. Kacy Cullen and Douglas H. Smith, on page 52. The authors describe efforts to connect prosthetic arms and legs directly to the nervous system. The technology would let the brain sense the limbs and control them—creating artificial limbs that would feel and move like real ones. At this point in development, the interface involves laboratory-grown nerve fibers and electricity-conducting polymers. But the potential for more is clear. In upcoming years, who knows?