One of the prevailing Avengers: Endgame fan theories out there says that the remaining Avengers will travel through time to beat Thanos and undo the snap. The heroes will supposedly move through time and universes to gather their own Infinity Stones, which they could use to wield tremendous power like Thanos did in Infinity War.
Doctor Strange is the primary candidate for messing with time, but he died in Infinity War, giving the Time Stone to Thanos just minutes before he did. However, Strange did see more than 14 million versions of the future battle against Thanos including the only outcome where the Avengers manage to beat him. In other words, he’s still going to play a significant role in the events that are about to happen in Endgame. Many expect Strange to have used the Time Stone on Titan to make sure certain events unfold in a particular way, the snap and his own death included. Now, a new fan theory argues that Marvel has hidden a time loop in plain sight in Infinity War, but we may have been too busy with other things to realize it.
Reddit user dat__dan713 argues that the battle on Titan is in a time loop, and that Star-Lord’s readings are a hint that everyone on the planet may be temporarily stuck inside the loop.
As the Endgame trailer shows us, everyone did die in Infinity War, so the time loop isn’t meant to allow them to defeat Thanos on Titan. That’s not how victory will be attained. Let’s not forget that many people blame Star-Lord for allowing Thanos to win on Titan, but that only happened because Strange never interfered. The magician could have stopped Quill from reacting impulsively to the news that Gamora died, but Strange didn’t do anything. This is the only way they can ultimately win, the doctor would tell Stark later in the film.
However, you don’t get to travel to the future to see over 14 million variations of future events without needing some time to do it. And that’s where the time loop may have helped. Strange needs time to see everything unfold, so he may require a temporary time loop to ensure he’s in control of everything.
If you recall in Dr. Strange’s solo film, when Strange originally fought Dormammu he used the Time Stone to create a time loop allowing him to move through alternate timelines, trapping Dormammu in a loop. The spell itself showed two rings on his upper and lower forearm (the lower one being smaller and tighter, and the upper being wider) it featured an open Eye of Agamoto with the stone glowing. Similarly, when Dr. Strange was viewing alternate futures in Infinity War it showed similar runes and bands, the only difference being it was on each arm and there was glowing green energy surrounding him. Which I gather to imply a heavier workload on strange and the stone.
The Redditor argues that Thanos pulling Titan’s moon over Tony Stark during the battle is what causes the axis tilt that Star-Lord measured:
A scene from Infinity War featured Star-Lord taking measurements on Titan, in which he said the planet was 8° off its axis and its gravitational pull is all out of whack. Before and during the time these measurements were taking place, strange was busy reviewing futures.
The theory says that the moon crashing into the planet is what could have caused those strange readings, and it all happens so fast that nobody other than Strange could be aware of it:
[W]hat I’m getting at is that Dr Strange began his spell before star lord started measuring, and as he was doing so Strange creates a time loop of sorts that has clearly already taken effect, where the repercussions of the moon’s impact are already seen before it actually happens. Now I’m not implying to know or grasp the big picture of this theory I’m only describing the idea that popped into my head after rewatching [Infinity War], and I assume others could add this to work in concert with some other Strange/Time Stone Endgame theories.
I do have a problem with this theory. Regardless of the order of events, an action in the future wouldn’t mess with the next version of the loop. The whole point of time lops is to be able to relive the same event without worrying about the consequences.
In Doctor Strange, whenever Strange dies the time loop resets, along with everything else. Only Strange and Dormammu are aware of what’s happening. Similarly, in Infinity War, the moon crashing into Titan shouldn’t interfere with Star-Lord’s readings in a separate iteration of the loop.
I do think that Strange has spent a ton of time investigating all those future events though, and possibly interfering with other versions of the past and future. He may not have needed to use a loop for everyone else, but only for himself to make sure whatever happens in alternate futures, he’d be brought back on Titan where he’d be able to keep reviewing alternate futures. That way, Strange wouldn’t care about dying while messing with the future or past, and he’d always be able to return to the same place on Titan right before Thanos arrives.