Do alternate universes partake in the sci-fi category?

Question

Question explains all. It may be somewhat stupid as a question, but I really don't know.

Answer 1

Alternate universes has been explored from Kurt Gödel, the mathematician, to Everett and many others. They can be resumed in the different categories:

- Those who are purely mathematical such as Gödle.

- Those who are a way to explain a 'hole' in quantum mechanics (M and branes theory), and

- Those who are purely philosophical like: If there is free-will then there must be several alternative paths (universes).

But those are all speculations. We are far from finding anything plausible. So, it is mostly science-fiction, so far.

Note that science-fiction also introduce things like time travel and faster than light-speed travel. That is needed in order to write intersting storyboards but far from reality or even possibility.

Many ask why the speed of light can't be overcome. Well ... it is in the definition. The speed of light is the constant that relates time and space. Move in one and you'll move in the other. If you leave earth with a spaceship that has a constant acceleration of one gravity (convenient because it makes you feel like on earth) about half a century later you'll reach the speed of light. If you carry an inertia navigation instrument as those found on aircraft, you will notice that it shows that you eventually exceed the speed of light. But are you? Anybody on earth will see that your mass increases to the infinite and you stop accelerating. You will observe your destination as slowing down too. But ... are you really moving at all? In relation to your own frame of reference, you are not.

It makes the question of the speed of the light irrelevant, doesn't it? But it looks great in science-fiction!