Plenty of science fiction writers have presented their visions for the future, and in my opinion most of them have gotten it flat wrong. So here’s my list of predictions for the year 2100:
Governments have grown extremely oppressive (more so than they are now, if believable), driving the move of humans into space. Earth based governments try during the latter half of the 21st century to assert control over nearby territories, like the moon and earth orbit, but fail miserably due to the widespread usage of orbital bombardment by space settlers and simple lack of experience. Such government is therefore largely contained to earth, the space settlers not allowing earth flights beyond orbit. The usurping of such unjust governments on earth has begun to happen, and is expected to be complete no later than 2120.
Of the few hundred-thousand to million humans in space, most live in the asteroid belt with the de facto capital at Ceres. There’s a wild-west style vigilante anarchy in the belt and open space, a weak confederation style government on Mars and the Moon. Never before had there been such a time of such personal liberty for humans. Science and technology have begun to advance at a remarkable pace due to the achievement of Singularity, and a significant amount of humans now have indefinite, disease free lifespans due to nanobots. The nanobots, however, came about in the mid-21st century, thus of the people then were still alive and thriving by 2100. A new species of post-humans is beginning to take form, using cybernetic enhancements and genetic engineering to advance themselves to new levels. The terraforming of mars is taking place, and post humans are able to use their advanced cybernetics to venture beyond the pressurized colonies without space suits or additional oxygen years before baseline humans would be able to.
Faster than light travel is still science fiction, though research is being done. Anti-matter pulse powered city ships are making decade long interstellar voyages a reality, settlements being established around Alpha Centauriy and Brenard’s star among other locations, though there are less than a dozen ships in service. First contact with an alien intelligence probably occurs around this time, in which it is discovered that humanity’s mastery of spaceflight is highly unusual, most planets having missed the window of technology and willpower necessary. Inside the solar system, voyages between worlds and asteroids take anywhere from months between the outer and inner planets, to about a week or two between the moon and mars or venus thanks to fusion powered plasma-ion engines. The majority of trade occurs in the belt, due to easily controlled environments, plentiful resources and low gravity wells. Cloud city style cities have sprung up in high venusian atmosphere, and are exporting mass quantities of oxygen derived from Venus’s mostly CO2 atmosphere.
This is my rather idealistic take on the future, take it as you will.