The future doesnt actually exist, it exists potentially and there is an infinite number of events that can happen at any given moment. I suppose imaging the future is pretty similar to imaging other possible worlds. In both cases we use our imagination and yes they do affect us in the present, and our choices. Even the act of daydreaming about a possible world is taking up actual time in this world that could be spent on something else. There must be a connection between the actual world and possible worlds because everything is all one at the end of the day, all things that exist are part of the whole. The shamons who claim to experience other possible worlds do so mentally / spiritually since their bodies are still here in this world while they are tripping! I guess the extent to which possible worlds change the actual world is dependent on their influences over the choices we make, it is our choices afterall that inform our actions which result in changes in this actual world.