The Chronovisor. What is it?

[Schmoe1]

When you look at time dilation, like when someone is very near a black hole, time for them will move very slowly, while someone far away from the black hole will experience "regular" time.  The person near the black hole would come back about the same age, while the person far away will have aged decades at least, depending on distance.  

I guess that's a form of time travel, but I don't believe in time travel to the past.  That would mean time itself is a traversable object and not linear.  Time is a man made unit of measurement.

I'm no physicist, but those are my opinions based on things I've read.