Samurai Jack - Samurai Jack Theory

Was it ever explained that Aku himself created the portals in time?

Cause otherwise, Past Jack is now sent into an Aku-less future, while Current Jack has assumed Past Jack's life, because he still has his memories of the future (since there was no implication his memory was wiped), maybe the portal is for Past Jack in the now Aku-less but probably just as dangerous future.

just my crackpot theory.