The multiverse theory suggests that our universe is only one of an infinite number of parallel universes.
Multiverses, or parallel universes, were first proposed by Schrodinger back in 1952. The theory would explain why our universe has the perfect conditions for life – with infinite possibilities, life was bound to exist in one of them!
There are some differences in multiverse theories. Scientist Max Tegmark has grouped multiverse theories into four main types:
Type 1 – This type thinks that there are an infinte number of bubble-like multiverses within our existing universe, all with the same laws of nature as our own.
Type 2 – This type suggests that within our expanding universe, “bubbles” of space, sort of like how water droplets form bubbles on plastic rather than spreading out. Sometimes these split, creating extra multiverses with different laws of physics than our own.
Type 3 – This “many worlds” theory is probably the most famous type. It suggests that every possible universe exists. If you flipped a coin and it landed on heads in this universe, in another universe, it has landed on tails.
Type 4 – The most theoretical, this type claims that all universes that can be described by maths equations are equally real.
There are problems with the multiverse theory. Firstly, there’s no evidence, and secondly, there’s no way to test it. For scientists, if you can’t test something, that’s a deal breaker - if there is no way to prove it, it’s a philosophical debate not a scientific theory.
But if it were true, does your doppelgänger exist in a different multiverse? Absolutely. Because the multiverses are infinite, then statistically, in one of them you are as famous as the Kardashians, in one you breathe fire and in another you are the smartest person alive.