Cosmological Puzzle: Why is the Universe Three-Dimensional?

The physicists have developed an out-of-the-box theory that 13.8 billion years ago the universe was filled with knots, which were formed from flexible strands of energy called flux tubes that link elementary particles together, according to a study published in the European Physical Journal.

This natural tendency for things to tangle may help explain the three-dimensional nature of the universe and how it formed.

In this study the hypothesis of the scientists suggests that at the early stages of the development of the universe, most of the matter of the world was in a state of quark-gluon plasma. 

During the phase transition of the quark-gluon plasma, protons and neutrons formed in the plasma, forming nuclei of chemical elements. The three-dimensionality of the Universe can be explained by the fact that the nodes of power tubes that connected quarks and antiquarks could only be stable in three-dimensional space. 

The flux tube system, penetrating the world with a higher number of spatial dimensions, could not exist for any period of time.

"We've taken the well-known phenomenon of the flux tube and kicked it up to a higher energy level," said Kephart, professor of physics at Vanderbilt.

According to online publication Phys.org, “Kephart and his collaborators realized that a higher energy version of the quark-gluon plasma would have been an ideal environment for flux tube formation in the very early universe.”

The large numbers of pairs of quarks and antiquarks being spontaneously created and annihilated would create myriads of flux tubes.

Hence, by this theory the entire universe could have filled up with a tight network of flux tubes. When the scientists calculated how much energy such a network might contain, “they were pleasantly surprised to discover that it was enough to power an early period of cosmic inflation,” the publication reported.

"Not only does our flux tube network provide the energy needed to drive inflation, it also explains why it stopped so abruptly," said Kephart. "As the universe began expanding, the flux-tube network began decaying and eventually broke apart, eliminating the energy source that was powering the expansion."

The net result is that this inflation would have been restricted to three dimensions only and any additional dimensions, if they exist, would remain minuscule in size, far too small for humans to perceive.

The next step for the physicists is to work out their theory until it makes predictions about the nature of the universe that can be tested.