How does the concept of time travel in science fiction explore the 2 dimensions of time - past and future?

In Science Fiction, the concept of time travel explores the two dimensions of time - past and future - by allowing characters to journey backward or forward in time, altering events and potentially changing the course of history. This exploration raises questions about the consequences of altering the past and the possibilities of shaping the future, highlighting the complexities and paradoxes of time itself.