All You Zombies
en.wikipedia.org
en.wikipedia.org
I had no idea it was based on a Heinlein story.
https://ipfs.eternum.io/ipfs/QmSiaEmhLvFdzzvkBmJKtRDmZRNDpDt...
That's a fun one.
Maybe next time I'll be the individual reading this comment.
Probably not, but it's a fun idea
Thank you for participating.
There are many distinct models of time travel, some self-consistent and some not. You are describing one you like, but this does not tell us much about how time travel works in the actual universe, if it occurs at all.
Of course, this isn't as romantic or digestible as time-travel as envisioned in most fiction (BttF).
You would be breaking conservation of mass/energy, though. Either you restate 'conservation' such that it applies across all universes instead of just within one (and you are moving energy/mass , in which case the number of timelines has to be fixed (which leaves open the possibility of paradoxes), or you're still violating conservation by creating entire universes every time you fork the timeline.
There are ways to get it all to work out, but they are all pretty weird and unintuitive. The first is that paradoxes are simply not permitted (or more accurately, can't be observed) and that the universe hides attempts to create them the same way it hides information that would violate the uncertainty principle.
The other main way you can resolve it is by asserting that while there are an infinity of parallel universes, and more are being spawned all the time, just as many are merging, keeping the number of universes at the same infinite number. Time travel is then permitted to spawn a new universe as long as the books remain balanced. Of course, the easiest way to balance things is for any changes to not matter enough to prevent timelines from merging again.
https://en.wikipedia.org/wiki/Time_Enough_for_Love
which is popular among poly people but is one of the very Heinlein books I didn't read when I was a kid, maybe because being the story of a 2000-year old man it's crazy long. (It doesn't help that Heinlein had serious health problems after he wrote "The Moon is a Harsh Mistress" and that everything he wrote after that had quality problems)
Let's not forget "The Door into Summer".
(Actually though I tell people who like Heinlein that Joe Haldeman set out to out-Heinlein Heinlein and was successful with "The Forever War" and "Worlds")
Just like "The Forever War" is a reply to "Starship Troopers", "Worlds" is a reply to "The Moon is a Harsh Mistress". I would put "Worlds" in a category like Pohl's "Gateway" (but not the sequels to Gateway) in that it reads more like literature than genre fiction.
The copy of Worlds that I have has a false copyright date (I think 1954) and I was thinking "... they didn't have lasers in 1954" and "... they sure didn't have O'Neill colonies in 1954". I think the fake date was no accident but part of the homage.
Personally I think you should beam yourself into the past and tell your former self to read Worlds... It's that good.
Side note: am I the only one who loved "Gateway", when the Heechee and their ships and artifacts were mysterious and almost unknowable -- the whole "we think ships of size 5 or 1 are dangerous. Also these colors are probably good, and we think these are bad" -- but was disappointed when the Heechee finally made their appearance and lost some of their mystery?