I was thinking about time travel today while watching Smallville online. Clark Kent was given a ring which could be used for time travel. I was thinking if someone went back in time, for sure they would change things, which means the possibility exists that their new future self would not go back in time, such that when the person went back to their own time another version of them would be there. it confuses me greatly as to whether time travel is even possible, or if you go back you are going to a different reality and when you go back to your own time you are going to yet another different reality.
also I am troubled by the magical compass that was passed back and forth between Richard and Locke ... the compass seems to be in an eternal time loop and has no entry point into that time loop ... it also seems that the compass is new in 1954 but old in 2007, so maybe the compass doesn't travel in time at all, only it's position changes ... the compass ages normally ... if the compass we alive and had memory, it would have experience being given to Richard in 1954 then given to Locke in 2007 and that's it ... no before and no after ... a singular experience ... but the compass is not alive, therefore it observes nothing, so I guess we will never know.
I don't think object duplicate in time travel ... Miles may have seen himself as a baby through the window, but I am sure he did not come into contact with himself.