Time is nothing but the length of events that happen one after the other.

Time is born out of an event or an action of something. Where there is no event, there is no time.

With the creation of the universe, cosmic time and space are born. As soon as these cosmic events, which are happening successively one after the other, stop, time will also stop.

You are nothing but a short-lived character in this gigantic cosmic film, consisting of one frame after another.

In this movie, as a character in a mega serial drama, it is not possible for you to go to the past or the future of this movie.

So, 'Time travel' is an unrealistic fantasy. Surprisingly some people see science in this fantasy! Also there are many scientists among them !

They also continue to call various hypotheses about time as science. In reality, time is nothing but the length of events that happen one after the other.

Everything that is happening in the universe, including the multi-universe, is predetermined (Please see my article about 'Destiny'). Just like a film or a video.

As it's possible to watch a film or video by moving forward or backward, it may even be possible for a viewer outside the cosmos to watch the film or video of this cosmic-event-stream by moving forward or backward.

Because of that, neither you nor I, as a character in this video, can forward or backward the film or video as a viewer outside the film or video. So, 'Time Travelling' is an unrealistic idea.