Your statistics is why I believe time travel is impossible. An object would never appear in the same place, forward or backward. Earth, Solar System, Galaxy are so far from the point of departure, that said object could appear inside an asteroid or in deep space, etc. I doubt future minds/computers/AI can pinpoint an exact place and time. The calculations are almost infinite. The only time travel will be through the supernatural or beings from another dimension.
“You forgot the Milky Way galaxy traveling throughout the universe.”
Absolute fact, I did indeed forget that additional plane of movement. The combination of influences in total is just absolutely incredible. It’s a train wreck waiting to happen.
In addition, I am one of those who believe that our universe is just one of many. They might be as numerous as the galaxies we just can’t see the others yet. If so, what would be the pattern of movement be in all these?