More universes

[David90]

Here we go again: Is there a multiplicity of universes ? In series or in parallel or both ? All at different stages of development ? How many is a multiplicity ? If there was an infinite number of universes, all things would be possible ? Is there a universe where I am manager of Arsenal and we've just been relegated to league 2 ? Is this my definition of Heaven ?

[jake-the-peg]

There are two distinct ideas about multiple universes but in both cases it is strongly speculative.

Firstl we speculate about this because certain apparently unrelated fundamental constants seem delicately balanced to permit the existance of stars or even matter itself.

Things like the strength of gravity, the charge of the electron and a number of others.

The idea is that there are many Universes with different values but we see these as delicately balanced because we require that to exist.

The Anthropic principal.

But really we have very little idea of how these constants come to have the values that they do. It might be that although they seem to be unrelated, that in reality they are not.

Secondly in Quantum mechanics there is what is called the Many worlds interpretation.

QM gives us powerful methods to predict and model what happens in certain circumstances, what the probabilities of certain outcomes are. It doesn't how ever tell you about what is "happening" inside the box.

Ideas about that are called interpretations one is the many worlds one.

The idea is much as you describe but there is no way to test whether or not it is true - so it's not really what I would call Science.

It's the sort of game that mathematicians and theorists play when they think there are no experimentalists about!