Something in 6 months in the past...

[tmntsplinterfan1997]

Since Fugitoid sends the Turtles, April and Casey back 6 months before Annihilation Earth occurs, there's something about time travel as the Turtles and their friends collect the black hole generator pieces.

Do you think the past versions of the Turtles, April and Casey are still on Earth with Splinter and the Mighty Mutanimals?

[Cure]

Of course they are.

[tmntsplinterfan1997]

Yeah. That's one thing I don't get.

[Powder]

Time is linear; the past, future, & present all occur simultaneously.

[victory_angel]

Think of it as copying and pasting something to another story line. So the Turtles themselves are living their lives on earth blissfully unaware of the horrors that will occur within the next few months.

And in the mean time there is copy of themselves from the future looking for the device that causes said horrors so they can prevent those horrors from occurring.

[TigerClaw]

Think of it as copying and pasting something to another story line. So the Turtles themselves are living their lives on earth blissfully unaware of the horrors that will occur within the next few months.

And in the mean time there is copy of themselves from the future looking for the device that causes said horrors so they can prevent those horrors from occurring.
The big question is, what will happen when they succeed? will time just reset and the Turtles will be back where they started? Will they have memories of what they did, or they will not remember anything that has happened due to the new timeline that has been created.

Time travel can be very tricky to explain.

[cookie jar]

Since Fugitoid sends the Turtles, April and Casey back 6 months before Annihilation Earth occurs, there's something about time travel as the Turtles and their friends collect the black hole generator pieces.

Do you think the past versions of the Turtles, April and Casey are still on Earth with Splinter and the Mighty Mutanimals?

Yes the past versions are still on Earth.
Read what Peter DiCicco one of the writers said about this
As for the time travel, yes the versions of the Turtles, April and Casey from six months in the past are still on Earth. The theory can get a bit complicated, but we’re basically going by Back to the Future rules of time travel.It would be easier to illustrate in a graph, but think about it like this. Let’s say, for example, Fugitoid picked up the Turtles & co. on today’s date, October 30, 2015, and took them back in time six months to April 30, 2015. The original versions of Leo, Raph, Donnie, Mikey, April, and Casey that existed on April 30th, May 1st, etc. are still there. They didn’t magically disappear because Fugitoid picked up the Oct. 30 Turtles, not the April 30 Turtles. But the Oct 30 Turtles now exist on April 30 as well. So if they decide to go back to Earth now, they will risk running into their past selves.
As it is on the show on Earth now, those Turtles, April and Casey, as well as Splinter, Kirby, the Mighty Mutanimals, Shredder, and the pizza guy are all living the events we already witnessed, unaware anything is different, while our Turtles go across the universe with Fugitoid and try to stop the Triceratons.

http://peterdicicco.tumblr.com/post/132220966732/hey-just-got-around-to-seeing-the-season