Britannica Sources used in this answer

How can a many-worlds multiverse coexist with an eternally inflating multiverse?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Discover the difference between the observable universe and the whole universe — Multiverse Learn about the distinction between the observable universe and the whole universe.

A many-worlds multiverse and an eternally inflating multiverse can coexist because they arise from different physical frameworks and operate at different levels of reality, allowing them to be combined or nested within one another.1

The many-worlds interpretation of quantum mechanics suggests that the universe branches into noninteracting worlds whenever a quantum measurement occurs, with each possible outcome realized in a separate branch. In contrast, the eternally inflating multiverse is a model based on cosmology where exponential expansion creates an infinite number of distinct, post-inflationary "bubble" universes within a common space-time background.12

These models are not mutually exclusive. Cosmologists have proposed that they may coexist in various ways: for example, an Everett-type (many-worlds) multiverse could consist of multiple branches, where each individual branch is itself an entire, eternally inflating multiverse. Alternatively, these processes might function as independent mechanisms that together populate the broader landscape of reality.1