Alternate reality

It can be considered an alternate reality whenever two versions of the same event occur with different outcomes, possibly explained by the fact that some events occur in different timelines or universes. The contradictory events can be considered as alternate timelines (if they are a result of time travel), or as alternate universes (when probabiliy and quantum mechanics make things unfold differently without any travel through time occurring.
 * In fan fiction and canon stories alike, an alternate reality can be used as a main story point, or it can simply be created after the fact to explain why events contradict each other.


 * For example, the fan series Star Trek: Pendragon is based on a main story point that they are an alternate reality where things happened very differently than they did in the history of Star Trek'' canon.


 * Other series that end up contradicting each other as a result of not being related to each other are usually explained as being alternate realities that differ in superficial ways not related to the story. Example: One ship has different registry numbers in two different fictions.