Kennedy's assassination was the first big global news event I remember (sitting in front of the fire on a damp Saturday evening in November, hearing the BBC radio news report, aged 8, while my mother was ironing the weekly wash (here's a later TV bulletin on the same day)), but a couple of years before that Kennedy and Khrushchev had narrowly avoided a global nuclear war during the Cuba crisis and a future grimmer by far than any we've lived through.
The Apollo 11 moon landing killed every future with easy travel to other planets stone dead. As soon as Neil Armstrong set foot on the lunar dust, the political point of the enterprise had been made. Half a dozen missions followed, more or less because the hardware was in place, but that was it for manned space travel beyond Low Earth Orbit in the Twentieth Century. No wheel space station, no mission to Mars or beyond, none of the cool stuff in 2001: A Space Odyssey. Twenty years later, Germans were standing on top of the Berlin Wall, the beginning of the domino collapse of the Soviet Empire and the end of the Cold War and hundreds of fictional futures in which the US and Russia were locked in perpetual struggle. And on 9/11 in the real 2001, the future was changed again, and we're still dealing with the effects. Maybe the Arab Spring will be another game changer; as Zhou Enlai is supposed to have said when asked about the changes caused by the French Revolution, it's too soon to say.
Apollo 11, the fall of the Berlin Wall, and 9/11 were all enacted live, on television, which is how we get our history these days. That, and Twitter and other social platforms. 'I've seen things you people wouldn't believe,' Roy Batty says, at the beginning of his soliloquy in Bladerunner. So have we all, Roy, without leaving our homes. That's a game-changer, too.
And these days everything in the world is connected to everything else. You're a mouse click away from Armstrong's first footstep, or Times Square (as I type this, in London, it's raining, in Times Square). Less than two years after the fall of the Soviet Empire, a couple of hundred kilometres to the north of the Berlin Wall [EDIT, actually about five hundred kilometres southwest], in CERN, Switzerland, Tim Berners-Lee set up the first web site. The World Wide Web rendered thousands of fictional futures redundant, but created thousands more. And that's the thing, if you're a science fiction writer. Every future you create will be undermined by history sooner or later. Usually sooner. But science fiction isn't - or shouldn't be - in the prophesy game. It can be about realistic futures, but it isn't especially into realism. It can parody present trends or inflate them into widescreen phantasies; it can contrast human stories with the pitiless scale of the universe. Most of all, it can tell us in as many ways as possible that the future will be different, wilder and stranger than we can imagine.