I’m not sure what to say to this one. I know they are predicted to exist as part of some current theories of physics. But I believe these theories are a bit controversial. Part of the problem is that it is going to be very hard to do the experiment to show whether or not they exist!
First of all, I am not a physicist, and most of those I do talk to, don’t seem to like the idea, though they concede it is consistent with experiments.
I think I do, because I’ve tried to understand quantum mechanics, and the only way it makes sense for me is if there are parallel universes (I am talking about the “many worlds” interpretation of quantum mechanics – I think there are other ways in which there can be multiple, not parallel, universes in physics). The other alternative is that there is something “random” at work in everything that happens (which chooses the way the universe turns out), and I don’t like that idea so much. I don’t think there’s any way to distinguish the two ideas experimentally.
Hi again! I’m not sure about parallel universes – they sort of drop out of some mathematical theories of the universe. They don’t seem very useful to me, but that is probably me. Sometimes there are things which are true, which just show up how our thinking is limited – for example quantum mechanics says that things can be both particles (like atoms) or waves (like light) at the same time. This doesn’t seem to make sense, but it is experimentally clearly true, its just that we can’t have a mental picture of a ‘wavicle’ I wonder if the same is true of parallel universes – its just we can’t quite imagine it…