Are all universes in different dimensions

astrophysics Our universe: Expanding bubble in an extra dimension

The standard model of cosmology is a fine thing. It explains pretty well mathematically how our universe evolved. But there are a few catches. Because it says that the universe consists of 95 percent dark energy (referred to as lambda in the model) and dark matter (CDM - cold dark matter). There are many theoretical statements about what dark energy and matter are, but no practical evidence. And the movements of some galaxies, according to the latest research, do not exactly match the model either.

We need more dimensions

But what would the alternative be? For example, a model with an extra dimension in the form of a "dynamic object embedded in a higher-dimensional space". This is what researchers from Uppsala University write in an article that has now been published in Physical Review Letters. In a communication from the university they explain it this way: "Our universe rides on an expanding bubble in an additional dimension."

Ulf Danielsson is an astrophysicist at Uppsala University and one of the authors of the publication. He describes the model that could completely change our conception of the universe in a little more detail in his blog:

Our three dimensions of space correspond to the edge of the bubble, while the radius of the growing bubble is the additional dimension.

Ulf Danielsson, astrophysicist, Uppsala University

And in this bubble we see the dark energy, says Danielsson, but that is just an effect of the additional dimension. It is important, however, that the model is in accordance with string theory. All matter present in the universe corresponds to the ends of strings that extend into the additional dimension.

String theory describes the universe not with particles, but with strings. These one-dimensional objects manifest themselves through different vibrations, which, however, require significantly more spatial dimensions. Physicist Danielsson, for example, assumes nine spatial dimensions. Four of them (or 5 if you include time) are large, five are small and rolled up. But so far it's all just a theory, a model. The next step, according to Danielsson, is "to review all the math details and find ways to test the theory against observations."