No, my point was if something on earth reaches at such speed, will time slow down in reality? Reference of Superman and this episode belongs to fiction.

Yeah, actually i thought that may be i was the only one unclear about this thing, but now i see that we all are !.. I think waiting for upcoming episodes is the answer 😅

I appreciate that you guys help me understand how this misconception is made to make entertainment, even though it's bad because this TV source has my respect for showing the things that are scientifically possible and not just showing myths and misconceptions around. And now it's completely loosing it !

@Taladris, I think we don't have to wait, because it's not like they changed past but never came back to future. They return to exactly same time when they went. I guess it's flaw in this plot. Still waiting for creditable answer (No offense here)

Yes,like they say when travelling back to time, don't interfere unless necessary. Eventually coming back will always lead to new timeline due to such kind of interference & here was the question about existence of Zoom and it's massive effect on time.