Just when we thought that the universe was complicated enough as it is as a single entity, along comes the suggestion of a multiverse – the possibility of more than one Universe connected to our own. These universes could hold some of the mysteries of our immediate cosmos directly multiplying its complexity many, many times over.
The idea of alternative, or parallel universes has come under fire with cosmologists regarding the theory as loosely scientific with them querying: how can the idea of a multiverse be tested, exactly? Others suggest that to even consider the notion of, what they regard as, unobservable universes aggravates Occam’s razor – that among competing suggestions, it is the idea with the fewest assumptions that should reign triumphant. In short, you would need to assume a lot for a multiverse to be feasible.
Not everyone has blasted the idea though. Taking the concept as a cue to investigate its validity, some experts are scanning the cosmic microwave background radiation – the relic emission that crackled behind the contents of the universe when it was breathed into life – for disk-like structures that could point out collisions between our universe and others. Results brought to the table by ESA’s now defunct Planck space observatory has pointed to these cosmic bruises and points to the idea that our universe crashed into the others at least four times during its history.
However, until more evidence is found, the concept of us in our historical universe being repeated many times over in many other universes will have to wait.