[image: Alfred T. Kamajian / Le Scienze 418 2003]

If Inflation Is True, Then We Live in a Multiverse

Inflation is an inherently quantum phenomenon. It follows that it cannot end at any point in space at the same time. As a consequence, inflation is eternal; once it begins, there will always be at least one region of exponentially expanding space, from which new Universes similar to ours, or different, will originate. Therefore, we inhabit a Multiverse in continuous, unstoppable expansion, formed by a fractallike structure of non-communicating Universes

Soon physicists realized that the early versions of the inflationary model led to conclusions that contrasted with observational data. They predicted, for example, the existence of a massive number of magnetic monopoles or large inhomogeneities in the structure of the Universe, of which, instead, there was no trace.

So, thanks to the efforts of theoretical physicists such as Alan Guth, Paul Steinhardt, Andreas Albrecht, Andrei Linde, and Alexander Vilenkin, by the mid-1980s, the first inflation models were replaced by new models, which did not contradict the observations. Two of them…