The future - at least director Robert Zemeckis' idea of the future, as envisioned in 1989 - arrives, in our present space-time continuum, in 553 Earth days. That date, Oct. 21, 2015, is when "Back to the Future Part II" is set, and the movie imagines a world of flying vehicles, hoverboards, drone dog-walkers - and in the future a lot of stuff will float, apparently.