With regards to the arrow of time i think its the same problem as if you were traveling in a box at a constant speed, without seeing outside the box its impossible to know your moving.
This applys to time in the same way, unless you could in essence "stand out of time" you can never know if we'r actually going forward or backward through time.
Perhaps some method of partical mesurement will be developed in the future to track these currents of time.
This is one of the "biggies" in regard to the universe and the rules by which we percive it, this would seem to suggest that time travel is possible on an atomic level.
What I propse is quite simple; that time is a 4th dimension of matter that gives all events in the cosmos the ability to happen, since nothing can occur in an infinitely non-existent amount of time. Time depends on cosmic events to sustain it's outward progression, and therefore is indefinately sustained by those events.
This is an intresting proposal, this would indeed lead me to belive time travel at least at atomic level possible and that currents of time circulate the universe.
In these time currents time will past either faster(forward) or slower(reverse) when you enter these currents time will not change from your perception, and you wouldent notice a difference once you were out of that current.
The only way to mesure the time difference would be to have the ability to "stand out of time" which we currently dont have.
This leads to the possiblity that we travel through these currents quite a lot, as the current passed over us we wouldent be able to tell, to our perception nothing would have changed yet to someone standing "out of time" we would be either moving very fast or doing everything backwards.
I dont have the knoledge to take these principles to an atomic level and test them, indeed the yard stick its to be able to alter an atom so that it can travel through the time currents unaffect and mesure what current we are on be it forward or reversed mabey then we could get to the real question of how old is the universe?