Question: is it possible that there are parallel universes?

Adam Paige answered on 20 Nov 2012:

I think the idea for this comes from Schroedinger’s cat, a fantastic theoretical model to explain quantum physics. In this thought experiment, you imagine a cat in a box with a vial of poison, a geiger counter (to measure radiation) and a radioactive rock. If the radioactive rock decays (which is a random process) the geiger counter will ping and break open the poison and the cat would die. If the radioactive rock does not decay the cat will be safe.

With the lid of the box closed you cannot tell what has happened inside the box. Both the cat being alive and the cat being dead is possible. Once you open the box the cat must be only alive or only dead. According to quantum physics, before you look in the box the cat must be BOTH alive AND dead at the same time. Both possibilities exist at the same time. But when you look inside the box this changes things so that only one possibility is true.

It makes no sense in terms of our understanding of cats, but it does make sense about quantum particles, and our universe really does seem to behave this way. The implication of the maths of quantum mechanics is that two things occur together. We only experience one of these when we look, but it makes sense from the maths that the other possibility also exists, but in an alternate reality. So we may find the cat alive (hurrah!), but another identical version of us in an identical version of the universe has just found the cat dead (ahhh!)

It is totally bonkers, but I love parallel world theory and have thought it possible. It also makes for great superhero comic stories!