Shortly after the Korean War, due to the consistent threat from North Korea, the South Korean government secretly launched several new departments within the Defense and Offense sections, particular in the science field. Two of these were; S.Y.S. ( 시간 여행 실험 / sigan yeohaeng silheom, lit. ‘Time Travel Experiment’), a project dedicated to traveling to both the past and the future; and Y.Y.S. ( 영혼 여행 실험 / yeonghon yeohaeng silheom, lit. ‘Soul Travel Experiment’), which revolved about the possibilities of switching people’s minds, e.g. taking the ‘soul’ of one man and putting it into another man’s body and vice versa. Fast forward to today - due to the lack of success in S.Y.S. and some controversial cases in Y.Y.S., the SK government decided to shut both departments down, then transfer and combine the data of the two into a new department: S.Y.J. ( 시간과 영혼의 조합 / sigangwa yeonghon-ui johab, lit. ‘Combination of Time & Soul’).
Work Explanation of S.Y.S.: After countless of almost effortless attempts, the team managed to build a unique facility that creates a strong magnetic field that combined with high electricity produces so-called ‘exotic matter’, which forms a ‘tunnel’ or ‘loop’. At first the recordings seemed promising, however when actually tested, the force proved to be too much for solid objects, such as living beings, and the S.Y.S. project was halted as a result.
Work Explanation of Y.Y.S.: initially, this project had more success than S.Y.S. - by mapping the functions of the human brain, reading the details, such as memories, and then transfer them, Y.Y.S. ultimately became able to ‘swap’ minds and put them into other bodies. ‘Uploading and downloading souls’, to simplify it. Sometimes however, essential data was lost during the transfers.
Work Explanation of S.Y.J.: when the S.Y.S. and Y.Y.S. were set to be scrapped by the SK government, a professor proposed the idea of combining the two. He backed it by his theory that what if the dataflow of Y.Y.S. would be able to sustain itself through the ‘tunnel’ of S.Y.S. The founding of S.Y.J. temporarily saved the two original projects. But S.Y.J. team is pressed to deliver results. Fast. And therefore the team takes a lot of risks. Although far from safe, one of the team members gets his ‘data’ read and then sent through the ‘tunnel’, where it is swapped with a commoner from around the 1970’s – think of the dataflow as a bungee jump rope or yo-yo, bouncing back and forth between the times in the tunnel.
Now, my problem is; what would lead the dataflow to connect with this particular commoner?
Swiping it off as pure coincidence is too lazy, and despite my lack of Ph.D.’s, I highly suspect there would need to be some kind of strong energy field or source for the tunnel to connect to. I have considered radioactivity, but this idea seems somehow overused and doesn’t really make sense – why would there be anything that radioactive near commoners? Another solution could be a lightening strike that temporarily ‘shuts down’ the commoner, allowing the transfer, though I would prefer if at least nothing physical happens to the original body of this person.
Oh, and I have to add; the time has to be around 1970, due to the theory that it is impossible for a person to exist twice at the same time, meaning that the swap has to take place before the birth of the scientist, before he exists. That’s why, in this story, something like what happened in the movie 11AM would not be doable – in that movie, not only are they able to send their whole bodies back in time, they also exist twice within the same time frame.
TL;DR: A scientist sends his mind back in time, to around 1970, where it is swapped with a commoner – his mind now ‘lives’ in the commoner’s body and vice versa. How is he able to do this? How and why does it connect with that particular commoner?
I’m really just open to hear about ideas, suggestions, opinions about this possibility. You can take the explanations above into consideration, or just let your thoughts flow freely. The only thing I don’t want to hear, is the impossibility of this actually happening. I know it’s not possible. Doesn’t stop me from using it in a story though. And forgive me; the names of the departments/projects are only temporarily.
Search history: time travel, time machine, worm hole, black hole, various time paradoxes, quantum mechanics, closed time-like curve, worldline, cosmic string, alcubierre drive… I have also asked this a couple of other places, so if you're interested in the response from there, let me know. Also, just ask if you need additional details.