#multiverse bump

Some stories involving time travel seem to work on this set of rules, but none seem to delve into the specifics.

It's similar to the typical multiverse time travel that is more explored, but to differentiate, I'll call that "multiverse creation time travel." That would be the system where traveling to the past creates a new timeline to resolve paradoxes; Changes made to the past go into a new timeline while the time traveller's home timeline and history remains the same.

Multiverse bump theory is a less common take on this setup, where instead of time travel creating branching timelines, time travel takes you into other already-existing timelines. When someone tries going to the past, the history of their own timeline rejects them for being paradoxical, bumping them over to the next closest timeline.

TMK a few works of fiction use this setup quietly, but none explain or highlight it AFAIK. When a character goes to the past over and over, and the world changes in ways that are more and more different from the original timeline with differences further into the past than anything the time traveller touched, this setup is in play.

I think one interesting mechanic a story could play with is one where any timeline you've been to becomes locked-in as part of your history, along with the history of anyone who touched your history.

So let's say Alvin from timeline A goes 100 years in the past to change it, but gets bumped to timeline B. Timeline B is similar enough to timeline A that they think they changed their past.

Alvin then either goes back home, or to the "present" in timeline B. One way or the other, Alvin starts to figure out that it didn't work as planned, either because nothing has changed, or because of how the new future doesn't have a place for them, because they don't exist, or because there's a new version of themselves.