Time travel — moving between various focuses as expected — has been a mainstream point for sci-fi for quite a long time.
Establishments going from "Specialist Who" to "Star Trek" to "Back to the Future" have seen people get in a vehicle or something to that affect and show up previously or future, prepared to take on new undertakings.
Each accompany their own time travel hypotheses.
What is time?
While a great many people consider time a consistent, physicist Albert Einstein demonstrated that time is a hallucination; it is relative — it can shift for various eyewitnesses relying upon your speed through space.
To Einstein, time is the "fourth measurement."
Time gives another organize — heading — albeit routinely, it just pushes ahead.
I will continue later...