Avengers Endgame question (spoiler)

[JeenLeen]

I just watched Avengers Endgame this week, and a couple questions about the ending fight. Spoilers, obviously.

Spoiler: spoiling since opening post

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Where did Thanos' army come from? It seems like one ship -- and not a huge one -- came through the portal. Or was it his main ship with the entire army on it, but it just shrank (as things due while time traveling in MCU) and got to full size a bit later?

Also, the heroes all make a big deal about how they can't (or shouldn't) change the past. For reasons that may or may not make sense or be true.
BUT, with the fight with Thanos, don't we learn that the heroes concerns aren't true?
If Thanos-from-the-past teleports to the future and dies, he's no longer in the past to collect the stones and cause the future he comes to. Paradoxes like that, and breaking causality, seemed to be the heroes' main concern. But... guess it doesn't matter at all?

It still makes sense in the narrative of the movie, as the heroes didn't know changing the past wouldn't change the present, so they acted with reasonable precaution. But I would think them learning that would have some impact. And maybe it does/will in movies after Endgame.

Also, a short side question: the new Spider-Man movies, like Homecoming, don't seem to be on Disney+. Is that right? I thought I saw it streaming somewhere, but wanted to watch Endgame first.

[Dire_Flumph]

Spoiler: Endgame spoilers

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Yes, the inference was that the army on the field came from the ship, which shrunk to time travel through the quantum realm. Was the ship big enough? I would think so, especially if its primary job was a transport. I don't normally care for watching 3D movies, but this is one where I'm glad I did. It gave a much better idea of the enormous scale of the battlefield, especially the scene where the ship is firing at the ground.

And yes, all sorts of time oopsies happened in the movie. The upcoming Loki series on Disney+ may go into those, but at the end Cap was implied to have spent quite a bit of offscreen time fixing the time anomalies with the stones (and I'm guessing, probably also with the help of the Ancient One). For now it's really up to you to decide what he did while in possession of the stones before putting them all back (At the very least he seems to have created a pocket alternate timeline where he married Peggy, I refuse to believe that no one noticed her husband looked one hell of a lot like a supposedly dead Steve Rogers.)

This is all up to what's plausible to you, but given the power of the various stones, I'm more than willing to accept that Steve was able to iron out the timestream over the course of a few years.

Also, since Spider-Man: Homecoming and Far From Home are Sony movies, that will probably complicate them showing up on Disney+

[Grey_Wolf_c]

the heroes all make a big deal about how they can't (or shouldn't) change the past.

Spoiler: Time Travel

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There is only so many ways you can do time travel. Ignoring the timey-wimey Doctor Who approach ("whatever works for today's episode"), you can either do stable time loop (you can't change the past, and travelling to the past already happened in your timeline, so even if you didn't notice, your future you were already in your past doing stuff - see Harry Potter book 3 for a great example), single alterable timeline (Back to the Future), or you can do parallel timelines (you can't change your past, because it's in the past. You can only change other timelines, that sort of look like yours to start with, diverge the moment you mess with them, but those changes don't change your "home" timeline*).

As far as I can tell, the MCU decided to go with the latter approach, and thus is not that they "shouldn't", it is that the physically can't. Which gives fertile land to all manner of what-ifs, including the parallel timeline where Captain America marries Peggy, prevent Hydra from taking root in SHIELD, and once Peggy dies of old age, borrows some time travel particles from Pym and travels back to his original timeline to pass on his shield and die there. And a different one where an unreformed Loki escaped after the NY battle.

Grey Wolf

[Saintheart]

Spoiler: Time Travel

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There is only so many ways you can do time travel. Ignoring the timey-wimey Doctor Who approach ("whatever works for today's episode"), you can either do stable time loop (you can't change the past, and travelling to the past already happened in your timeline, so even if you didn't notice, your future you were already in your past doing stuff - see Harry Potter book 3 for a great example), single alterable timeline (Back to the Future), or you can do parallel timelines (you can't change your past, because it's in the past. You can only change other timelines, that sort of look like yours to start with, diverge the moment you mess with them, but those changes don't change your "home" timeline*).

As far as I can tell, the MCU decided to go with the latter approach, and thus is not that they "shouldn't", it is that the physically can't. Which gives fertile land to all manner of what-ifs, including the parallel timeline where Captain America marries Peggy, prevent Hydra from taking root in SHIELD, and once Peggy dies of old age, borrows some time travel particles from Pym and travels back to his original timeline to pass on his shield and die there. And a different one where an unreformed Loki escaped after the NY battle.

Grey Wolf

Spoiler: Endspoilergame of spoilers

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I've got to say the Endgame time travel concept is really doing my head in, and that's mainly because I don't understand how the Bruce Banner on one hand says you can't change your own past, but when talking with the Ancient One says that the Infinity Stones can be returned right to the moment they were removed from the timestream and thus restore that timeline to how it was. And the reason that has to be done is so the Ancient One's timeline doesn't splinter into a universe darker than the DCU.

Like I said, I don't get it. If you cannot change your own past, then the moment you remove an Infinity Stone from where it was in its own timestream, you can't change that event, it's become part of your own past. You've irrevocably doomed the other timeline because that cannot now be changed by putting the st...

...

Oh, wait. Now I think I get it. If Bruce takes the Time Stone from the Ancient One's timestream, and Cap comes back to the same timestream ten seconds later, then Bruce isn't changing his own past, and Cap isn't changing his past either - they are just visiting one timestream among many. And they aren't changing the Ancient One's past, either, since the stone comes back a second or two after it was first removed from the timeline.

The time travellers in Endgame aren't actually travelling through time at all, they're just jumping universes or timestreams. When Thanos comes forward from 2014, he isn't actually going to his own future; he's travelling to a timestream where the Avengers have killed a parallel Thanos and then gone on to recover the Infinity Stones.

Of course, what then goes on to really bake my head is how the Infinity Stones work in all of this. If all that's happening is a jump to different timestreams, then aren't there 6 x n[timestreams] infinity stones jumping around, available to be taken? Or is it that they only exist in one timestream at a time?

[Grey_Wolf_c]

Spoiler: Endspoilergame of spoilers

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Of course, what then goes on to really bake my head is how the Infinity Stones work in all of this. If all that's happening is a jump to different timestreams, then aren't there 6 x n[timestreams] infinity stones jumping around, available to be taken? Or is it that they only exist in one timestream at a time?

Spoiler: Stuff!

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Yes, if the MCU runs in multithread timelines, there are 6n infinity stones that you can access with thread-jumping time travel. And The Ancient One's concern was that if someone from a different thread steals her time stone, then her thread goes off the rails. Banner was never endangering his own time thread, just ("just") someone else's. Now, the explanation from TAO suggests that this is not full quantum theory splitting timelines - this is just that there are potentially infinite parallel timelines, but each timeline doesn't itself split on every decision or anything like that.

Grey Wolf

[Brother Oni]

Further to Grey_Wolf_c's answer, this is also seen in the Spider-Man: Into the Spider-verse with Miles Morales being in a different universe stream (his father is a PDNY police officer, many of the product names are different, eg Koca-Soda).

Spoiler: Spidey-verse spoilers

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This is used to highlight differences when the other Spider-men/women/pigs turn up, for example the Times Square Koca-Soda sign in Miles' universe is a Porka-Cola sign in Spider-Ham's universe and the Coca-Cola sign in the 'original' universe.

[Keltest]

Something else to remember is that the next Doctor Strange movie is titled "Multiverse of Madness" as well, and, to the extent that anything is known about it, involves much parallel universe shenaniganry that he is trying to fix/control/stop/manipulate/change.

[Precure]

Bruce was mistaken, it's just parallel universes.

[JeenLeen]

Thanks y'all.
It still sounds like the heroes rather misunderstood what they were doing, but maybe the Ancient One's clarification goes along with y'all are proposing. I don't have the mental energy to think it through now, but I feel a lot better about the internal cohesion of the movie now.

Like, I don't mind time travel plot holes, but it bugs me when the protagonist(s) are worried about things with time travel and then they turn out not to matter, and nobody really comments about it.

Also, since Spider-Man: Homecoming and Far From Home are Sony movies, that will probably complicate them showing up on Disney+

I forgot that Marvel just got to use him for those movies, and didn't own the other Spider-Man movies. Maybe I had seen them on Netflix before, but they aren't there now.

[Forum Explorer]

Bruce was mistaken, it's just parallel universes.

Mistaken on some of the details maybe, but is correct on the general idea that you can't go back and murder Thanos as a baby.

[JeenLeen]

Mistaken on some of the details maybe, but is correct on the general idea that you can't go back and murder Thanos as a baby.

Am I correct that Bruce's reasoning was this sort of paradox-loop
1. If we kill baby-Thanos, then the timeline changes to a no-Thanos timeline
2. If there is no-Thanos, I would never go back in time to kill Thanos.
3. Therefore, I would not have killed baby-Thanos... so timeline resets and I can't change the past to that degree.
The reason they wanted to take, then return, the Stones quickly was so that they didn't change the past to such a degree that the future would significantly change such that they would never travel to get the Stones.


That seemed to be the reasoning, as I understood it watching it late at night and not devoting a lot of energy to fully understanding his reasoning.

[The Glyphstone]

Just fall back on the MST3K mantra in situations like this. Or really, any movie plot with time travel except Primer.

[Cheesegear]

Also, the heroes all make a big deal about how they can't (or shouldn't) change the past.

They had an entire scene about this and how they aren't changing the past.
Endgame is running on multi-verse theory, which means they're ruining other universe's timelines, not their own.

What they don't want to do, is ruin other Universes by removing their Stones (Stones are tied to the creation of the Universe and the fabric of reality...Or something), hence the need to put them back.
The Universe without Thanos in it now, will just have to cope.

Nobody went back on their own timeline...Except maybe Steve? It's not clear. There's just Word-of-Director that says Steve is the father of Peggy Carter's kids. But how did that happen if Steve was shunted into the future, unless he went back? But he's not supposed to go back...So he probably just didn't, and it's something the Director(s) probably wanted to do at some point, but given the non-time-travel rules that Endgame presented (more like dimension-hopping), they decided that Steve going back on his own timeline was too hard to do, and then just didn't worry about it.

[Kareeah_Indaga]

Nobody went back on their own timeline...Except maybe Steve? It's not clear. There's just Word-of-Director that says Steve is the father of Peggy Carter's kids. But how did that happen if Steve was shunted into the future, unless he went back? But he's not supposed to go back...So he probably just didn't, and it's something the Director(s) probably wanted to do at some point, but given the non-time-travel rules that Endgame presented (more like dimension-hopping), they decided that Steve going back on his own timeline was too hard to do, and then just didn't worry about it.

I’ve just been hand-waving it like so: if ‘our’ Steve is from Timeline A, then ‘our’ Steve went to Timeline A+1 to marry Timeline A+1’s Peggy and have kids. The Steve who married Peggy in Timeline A is the Steve from Timeline A-1, but it worked out exactly the same for both of them so it doesn’t matter that it isn’t the ‘same’ Steve from a storytelling perspective.

I use the same explanation for the Mind Stone; it knows about Thanos because it got ‘borrowed’ by a different timeline’s Avengers for their Endgame face off with Thanos and then got put back, so it knew how everything was going to go down before it happened.

[The Glyphstone]

They had an entire scene about this and how they aren't changing the past.
Endgame is running on multi-verse theory, which means they're ruining other universe's timelines, not their own.

What they don't want to do, is ruin other Universes by removing their Stones (Stones are tied to the creation of the Universe and the fabric of reality...Or something), hence the need to put them back.
The Universe without Thanos in it now, will just have to cope.

Nobody went back on their own timeline...Except maybe Steve? It's not clear. There's just Word-of-Director that says Steve is the father of Peggy Carter's kids. But how did that happen if Steve was shunted into the future, unless he went back? But he's not supposed to go back...So he probably just didn't, and it's something the Director(s) probably wanted to do at some point, but given the non-time-travel rules that Endgame presented (more like dimension-hopping), they decided that Steve going back on his own timeline was too hard to do, and then just didn't worry about it.

Doesn't that mean Steve made out with his granddaughter in Civil War?

[Kareeah_Indaga]

Doesn't that mean Steve made out with his granddaughter in Civil War?

You mean Sharon? She was Peggy’s niece, so no.

[Dire_Flumph]

Doesn't that mean Steve made out with his granddaughter in Civil War?

Peggy was said to be her great-aunt.

It's still icky if Steve was her great-uncle (even if not by blood). It why I just prefer to assume that Steve married a Peggy from a time-stone assisted alternate pocket timeline.

[Rakaydos]

"5D chess with multiverse time travel"
https://www.youtube.com/watch?v=LOotGsWbaeA

This game, I think, explains Avenger's time travel quite nicely.

Until there is a time move, there is only the one board.
If you move back in time, though, it doesnt affect your own past moves- instead, it creates a parallel timeline where the time traveler has appeared from nowhere. Once alternate timelines exist, pieces can also move "sideways through time" into the different known timelines.

When Bruce explained that they couldnt kill baby thanos, he was saying that it would create a timeline without Thanos, but it wouldnt affect THEIR timeline.

When the ancient one explained that the stones had to be returned, it was because that timeline was in check from Duramou(sp?), and she could not allow her world to be destroyed for the CHANCE of saving another.

It's not that every board has to turn out perfectly the same after all the time-fixes. It's just a matter of not causing more problems than you solve.

[Cheesegear]

I’ve just been hand-waving it like so: if ‘our’ Steve is from Timeline A, then ‘our’ Steve went to Timeline A+1 to marry Timeline A+1’s Peggy and have kids. The Steve who married Peggy in Timeline A is the Steve from Timeline A-1, but it worked out exactly the same for both of them so it doesn’t matter that it isn’t the ‘same’ Steve from a storytelling perspective.

Two different dimesnions' Steves, go to each others' dimensions to be with that dimension's Peggy.
Then, when time comes, they each go back to their own dimension, with their own dimensions' versions of Peggy Carter who they never got with.

That's the stupidest logic I've ever read. Unfortunately, the math checks out.
Universe A, has children fathered by Universe B's Steve.
Universe A's Steve, gets to live his life with Universe B's Peggy.
I'm so angry that that makes sense.