Another possibility. There may be no past or future. There may be only the “Now”. What we call the past is just today’s matter in a different position. The same is true with what we call the future.

All matter is moving through space. Each atom takes it’s own path as it moves through this universe. Yesterday’s atoms are here now. They have not really change, just their placement in relation to a fixed point in this universe.

If this is true, then Time Travel may not be possible. However, if we could discover the path that matter takes, we could get a view of the past, or even recreate it- if we had the technology.