NoOneSpecial writes...

This may surprise you, but I have question about how time travel works

First let me preface this by saying that I agree with your preferred method of doing time travel as closed loops. Nothing changes the past because it was part of the past. Avalon Part 2 has always been a favorite episode of mine because I always loved how cleanly you explained the two Archmages working in a loop together. But I also understand that DC comics as a whole doesn't work the same way. Some of DC's most iconic stories revolve around time travel, so we have to get messy and roll with it.

1. When Mantis (who is now the MVP of S4) set the Time Sphere back one day to get the Phantom Projector, he created a closed loop of time travel. He didn't alter the past in anyway that prevents his future self from doing the same thing when he arrives later. Basically, Zod's team can't find the PZ projector because it's already been taken into the past by Mantis. So closed loops are possible on Earth-16, but they aren't necessarily guaranteed and require some skill to pull off?

2. Now we get messy. In 2020, Child kills Teekl and de-corporealizes Klarion. Klarion then travels back to 2010 and hijacks the school bus. He then bounces around time for a while until he arrives back in 2020. After Child's defeat, the bus is sent back. So, this would also be a closed loop? The problem here though is that the timeline was altered several times after Team Year Zero. E.g Bart arrives in 2015 and alters history by preventing the Reach Apocalypse and so does Lor-Zod. But this means events would play out differently than the original timelines. Which means Child may not have killed Klarion in Bart's timeline. Not to mention someone else could alter history again and maybe prevent Klarion's death from ever happening in 2020. Yet from what we see, the school bus thing was always Klarion. I guess I want to understand how this could a closed loop of time travel like in Gargoyles, when history is also subject to change in Young Justice?

3. I like the Chronotron radiation rule. Basically, if someone is dosed in this radiation, they are immune, or in future Neutron’s case, semi-immune to changes in the timeline. So this may be a spoiler question since it involves a hypothetical scenario, but it is based off what we’ve seen already. Let's say someone time travels back to Team Year Zero and mucks up history, resulting in a new timeline. What would happen to Bart, Lod-Zod, the Legionnaires and I guess Mantis and M'comm, who have all been exposed to Chronotron radiation? If it makes them immune to changes in timelines, then it stands to reason they would be unaffected if someone else alters history even further back. We know that Bart's timeline is gone, but so far, he has stuck around, and the Legionnaires survived Lor-Zod's changes because of the radiation. So, does the radiation make you time-proof forever or do you just need to be in proximity to this radiation and have a strong enough dosage when the timeline is about to be alerted?

4. When speaking to the Legionaries, Superman asked why they don't use their time sphere to go back and try to save Superboy. I get that Superman may not know the rules of how it works, but this brings me to another hypothetical scenario. Let's say, after Lor-Zod's first failed attempt to kill Superboy at the UN, he decides to just go back in time earlier and try again rather than wait for another chance. So, if he went back, like say a week, knowing where Superboy was and killing him, that would change history. So, what would happen to the Lor-Zod who would show up the UN a week later? Since Past-Lor-Zod has Chronotron radiation, he is immune to changes in history. Would that include ones made by his own future self, going further back into the past? Similarly, let's say the Legionnaires did go back to save Superboy on Mars, they would run into their past selves, who like them are immune to changes in history due to Chronotron radiation. So, would the duplicates stick around or be erased from the timeline?

5. I'm a bit confused by Chameleon Boy expecting there to be changes after talking to Superman. He initially thinks they failed to reset the timeline, but then Saturn Girl brings up their exposure to Chronotron radiation making them immune to changes. I mean Bart resetting the timeline didn't make him disappear or send him back to his future so why was Chameleon Boy expecting something to happen? Am I missing something in this exchange or was it just a case of Chameleon Boy being optimistic?