So I was wondering - when someone travels in time to another-then, would they also transport all of their micro-organisms along for the ride? Would their last meal from the other-then still be digesting in their gut, to be deposited in some bathroom within this-then? Would they have disturbed some delicate mass-energy balance equation by bringing along a snack from the other-then to this-then, and by eating it in this-then and convert it into heat-energy cause some backlash yinyang/ karma balancing process to kick-in? Would an entering time-traveller have to displace, say one-Tardis-full unit of 3D space/time/air/mass from its current location to somewhere-else/ somewhen-else? Would the same amount of mass/ energy need to be replaced upon exiting? Could this time-traveling mass-energy mis-matches be the origins of the "dark-energy/ dark-matter" that we are currently detecting in the this-then? Is the overall effect cumulative/ recursive?