The concept of a multiverse refers to the hypothetical idea that there may be multiple universes, each potentially with its own set of physical laws and properties. It's important to note that the multiverse is still a topic of theoretical speculation and does not currently have direct empirical evidence supporting its existence.
The notion of an "outside observer" who can simultaneously observe all universes in a multiverse is a complex one. The idea of an external observer implies a vantage point beyond the boundaries of the multiverse, which may not be a meaningful concept within the framework of the multiverse hypothesis.
If we consider the multiverse as a collection of separate universes, it is generally assumed that interactions between these universes would be limited or nonexistent. Each universe would likely have its own physical laws and space-time structure, making it difficult to envision a direct observational connection between them.
However, various models of the multiverse propose different mechanisms for how these universes could exist and interact. For example, in the context of inflationary cosmology, it is suggested that multiple "bubbles" or regions of space can form within a larger inflationary spacetime. In this scenario, the idea of an observer who could observe all the bubbles would be challenging, as the bubbles may be causally disconnected from each other.
Additionally, if the multiverse exists, it is uncertain whether any form of observation or interaction beyond individual universes is even possible. The laws of physics within each universe would govern what can be observed and experienced within that particular universe.
It's important to emphasize that the notion of a multiverse is still a subject of ongoing scientific inquiry, and various theoretical frameworks exist. While these frameworks provide potential explanations for the existence of multiple universes, the specific nature of an "outside observer" or the possibility of observing all universes at once remains speculative and open to further exploration and debate.