The 22nd century

 

A slowing of environmental destruction, rapid growth of transhumanism, and major developments in space travel all mark the 22nd century. Practically all the world's energy comes from either fusion or renewable sources now.
Artificial intelligence – having begun to merge with human intelligence in the previous century – now surpasses it, reaching whole new levels of cognitive and intellectual capability. Though lacking the raw emotions and subtle traits of organic human minds, the sheer depth and power of AI begins to profoundly transform the course of history. High-level decisions by governments and corporations now come directly from these sentient machines. There are vast swathes of virtual employees everywhere, and heavily automated systems in every industry. All of this makes for vastly improved speed, efficiency and productivity.
Science advances so rapidly that it would exceed the comprehension of 20th century observers. The most significant developments are in quantum physics, but wholly new fields also emerge that were completely untapped in the previous century. Femto-scale engineering is among the many practical applications resulting from all this.
Developments in space during this time include numerous permanent, manned settlements on the Moon and Mars; regular manned trips to the gas giants; huge mining operations in the asteroid fields; and the first probes to Alpha Centauri. Space tourism booms during this period, with trips to the Moon's surface and elsewhere becoming relatively commonplace.