Could there be time travel for non-physical entities?
Imagine the existence of independent, intelligent non-physical entities. Freely moving, unattached consciousness, not hindered or tied done by any limitations of a physical existence.
Future time machines might allow non-physical consciousness, detached spirits or souls to travel back to the past and re-live history without any risk of changing anything. It could be like watching a film. You can zap back and forward and even have the feeling that you sort of participate in it, but without having the slightest possibility to ever alter the story.
It is likely that time passes differently in a pure non-physical, spiritual world. Compared to our physical universe, time might stand still. What we experience as past, present and future in our physical existence might occur simultaneously in the spiritual or non-physical world.
How could technology get involved with this possible non-physical existence? High tech devices might be developed to temporarily disconnect body and soul. While the body of a person stays suspended, the soul can detach itself and go traveling about, communicate with other non-physical entities or re-attach itself to other bodies. Such a device could be the possible basis for a time machine.
The idea of disconnecting body and soul is not something new. Many people claim to have had out of body experiences, sometimes provoked and other times spontaneous. Future technology however might allow for controlled disconnection, precise travel itineraries and secure return trips and re-attachments of the soul to the original body. Such technology might help in finding other spirits and could facilitate communication.
If the above form of time travel is going to be invented then the consequences must be with us already. Testing and playing with such a time travel technology might have been responsible for any number of mysterious events and phenomenon recorded in our own history.