Apparently there is an aspect of Quantum Theory called retro-causality which suggests that something could be done in the future that would affect what occurred in the past; something you could do now that would change what happened then.

It all has to do with sub-atomic particle ‘entanglements’; apparently, simply observing one of an entangled pair changes the nature of the other one which alters what was a micro-second ago. Extrapolating from this brings into focus an idea sci-fi writers have been exploiting for decades: time travel. While some theoretical physicists are pretty sure time travel can’t happen I have to wonder: as I was passing a local elementary school recently, a question on the school’s electronic poster board asked: Do you have a student in Kindergarten next year? Any definitive answer to that question would suggest there are, indeed, people living in the future.