Scratch

Scratchthatguys wrote:

3. Alternate timelines. In this version of time travel, there are multiple coexisting alternate histories, so that when the traveler goes back in time, she ends up in a new timeline where historical events can differ from the timeline she came from, but her original timeline does not cease to exist (this means the grandfather paradox can be avoided since even if the time traveler's grandfather is killed at a young age in the new timeline, he still survived to have children in the original timeline, so there is still a causal explanation for the traveler's existence). Time travel may actually create a new timeline that diverges from the original timeline at the moment the time traveler appears in the past, or the traveler may arrive in an already existing parallel universe (though unless the parallel universe's history was identical to the time traveler's history up until the point where the time traveler appeared, it is questionable whether the latter version qualifies as 'time travel').

        James P. Hogan's The Proteus Operation fully explains parallel universe time travel in chapter 20 where it has Einstein explaining that all the outcomes already exist and all time travel does is change which already existing branch you will experience.

        Though Star Trek has a long tradition of using the 2.1 mechanic, as seen in "City on the Edge of Forever", "Tomorrow is Yesterday", "Time and Again", "Future's End", "Before and After", "Endgame" and as late as Enterprise's Temporal Cold War, "Parallels" had an example of what Data called "quantum realities." His exact words on the matter were "But there is a theory in quantum physics that all possibilities that can happen do happen in alternate quantum realities," suggesting the writers were thinking of the many-worlds interpretation of quantum mechanics.

        Michael Crichton's novel Timeline takes the approach that all time travel really is travel to an already existing parallel universe where time passes at a slower rate than our own but actions in any of these parallel universes may have already occurred in our past. It is unclear from the novel if any sizable change in events of these parallel universe can be made.

        In the Homeline setting of GURPS Infinite Worlds there are echos — parallel universes at an early part of Homeline's history but changes to their history do not affect Homeline's history. However tampering with their history can cause them to shift quanta making access harder if not impossible.

        A type of story which could be placed in this category is one where the alternative version of the past lies not in some other dimension, but simply at a distant location in space or a future period of time that replicates conditions in the traveler's past. For example, in a Futurama episode called The Late Philip J. Fry, the professor designed a forward-only time travel device. Trapped in the future, he and two colleagues travel forward all the way to the end of the universe, at which point they witness a new Big Bang which gives rise to a new universe whose history mirrors their own history. Then they continue to go forward until they reach the exact time of their initial departure. Although this journey is not exactly a backward time travel, the final result is the same.

        In the Japanese manga, Dragon Ball, the character Trunks travels back in time to warn the characters of their deaths soon to come. This does not change his time line, only creates a new one in which they do not die. Soon two of the characters destroy the lab where the monster Cell is being created, stopping him from absorbing the androids, creating a third time line. Later it is revealed that Trunks is killed by Cell in the future, then travels to three years before any of the events occurs, which creates a fourth time line. No matter what any character does in the past, their own original time line is unchanged.

Quoted from an article on time travel.

i love Timeline!!!!!!!!!!!!!!!