In the present article we put up for discussion the idea of there existing several versions/phases of
the vacuum, in the spirit in which we have long worked on this idea, namely the Multiple Point
Citicality Principle, which also says that these different vacuum phases have the same energy
density. We mention that we indeed predicted the Higgs mass to be (135 ± 10) GeV, which
when measured turned out to be 125 GeV, using the assumption of this Multiple Point Criticality
Principle. We consider the possibility that there is one type of vacuum in the galaxy clusters (the
usual vacuum) and another type of vacuum in the voids. The hope that there could indeed be
such a low tension 𝑆 of the domain wall between these two phases, that it would not totally upset
cosmology is based on our dark matter model. In this model dark matter consists of pearls or
bubbles of a new vacuum phase, with ordinary matter inside it under very high pressure. The order
of magnitude of 𝑆 1/3 ∼ 𝑀𝑒𝑉 𝑜𝑟 100 𝑀𝑒𝑉 could make such domain walls astronomically viable.
We successfully estimate the order of magnitude of the variations in the fine structure constant in
different places astronomically, but the similar variations in proton mass over electron mass should
have been much bigger than seen experimentally in our model. The Universe’s surprisingly early
galaxies seen by JWST (James Webb telescope) may agree well with our model. Replacing the
usual cosmological constant by domain walls in the standard cosmological model would lead to a
cubic root of the tension being 𝑆 1/3 ∼ 30 𝑀𝑒𝑉.