Are parallel universes and multiple dimensions the same thing?
Both of them are hypotheticals which have never been observed. In science fiction they are bandied around carelessly, so you would have to ask the writer. In current science, as I understand it, they are different things from different parts of modern physics. Parts which have not yet been reconciled – in part because both have no experimental proof whatsoever. Multiple dimensions comes from String Theory, which is trying to explain what particles “are”. String theory seems to want to add six or seven new dimensions to the four we know (3 space and 1 time). These dimensions are very small indeed so that a string can wrap wound the whole universe in them, but in principle we can detect them. Parallel universes come from quantum mechanics, as a way of explaining what seems to be the randomness of quantum effects. The idea here is that every time e “quantum decision” is made, the universe forks and the two possible outcomes happen in the different branches, In this case, each fork represe
