The Multiverse

Back when the Mundane universe was very young — less than a second old — in an incredibly brief amount of time, the universe underwent a period of rapid expansion, "inflating" to become many orders of magnitude larger than its previous size. Inflation of the Mundane universe is thought to have ended about 14 billion years ago. However, inflation does not end everywhere at the same time. As inflation ends in one region, it continues in others. Thus, while inflation ended in the Mundane universe, there were other, distant regions where inflation continued — and continues even today. Individual universes then "pinch off" of larger inflating, expanding universes, creating an infinite sea of eternal inflation, filled with numerous individual universes. Thus, the multiverse is created.   In this eternal inflation scenario, each universe would emerge with its own laws of physics, its own collection of particles, its own arrangement of forces and its own values of fundamental constants. This might explain why the Mundane universe has the properties it does — particularly the properties that are hard to explain with fundamental physics, such as dark matter or the cosmological constant. There are random cosmological constants in different universes, and it is simply a coincidence that the one within the Mundane universe takes the value that is observed.   With all the endless universes within the multiverse, there are those special universes that life exists. Certain aspects of the Mundane universe are special and important for supporting life, such as the longevity of stars, the abundance of carbon, the availability of light for photosynthesis and the stability of complex nuclei. All these features are typically not the case within a random universe and thus most of the universes within the multiverse do not have life. But there are those special few that harbor life.   Like the Mundane universe, all the universes within the multiverse are in constant motion. Because of this, there are times that various different universes come into contact with each other. Sometimes these universes merely graze against each other and other times these universes completely merge together only to then divide again. When universes come into contact with each other, they create Rifts between the universes that will transfer things between the two universes.