Out of fiction and fantasy has grown the concept that besides what we perceive, there may be entire universes that somehow match or connect at times with ours - what would be the point of imagining them if connection were impossible. An early and much repeated concept is that in our universe there are times when an important decision is made - WHAT IF at that point a parallel universe was created where everything was the same but the other decision or event was made - John Kennedy was not hit by bullets in Dallas, Hitler died in 1933, Johnson chose to run and Nixon never had a chance to infect us with paranoia - and so on.
There are more or less scientific versions of this also - not exact parallels of people and occurrence but universes where antimatter predominates, etc.
There are more or less scientific versions of this also - not exact parallels of people and occurrence but universes where antimatter predominates, etc.
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The universe is defined to be everything there is, so a parallel universe is strictly a science fiction story. A big part of science is conjecture, which means making up "What if" scenarios. Often those scenarios get discussed a lot for a long time, and people begin to assume they are true just because they keep hearing them. You have to be careful to keep everybody talking about reality, unless of course they are selling stories.
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In the same way that two parallel lines will never intersect, the term parallel is being used here to indicate any universe that does not intersect with our own.
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a universe where we are opposite