Why does the world around us have exactly three spatial dimensions and only one of time? A trio of physicists from the University of Belgrade in Serbia has offered a mathematical explanation, infohub.kz reports.
In a study published as a preprint on the arXiv portal, the scientists relied on a simplified model of quantum gravity. They modeled the geometry of the microcosm from virtual four-dimensional geometric figures — 4-simplices — to test what structure of space-time would form as a result of their random connection, without accounting for complex physical forces.
Simplices are multidimensional analogues of triangles: four-dimensional elements consist of three-dimensional tetrahedra, flat faces, one-dimensional edges and vertices. The researchers assigned random lengths to the edges, using the Planck length as the lower limit. For the calculations, they created three configurations of 100,000 elements: a four-dimensional ball with a boundary, a closed sphere without a boundary, and an unconnected set of scattered fragments. In total, the algorithms performed more than 20 billion computational evaluations.
The results showed that when the edges of the fragments are set as spatial distances with real numbers, the geometric blocks spontaneously assemble into a space with three dimensions of space and one dimension of time in roughly 85% of cases. About 6% of attempts produced a static Euclidean Universe without time, and 8% produced a world with two spatial and two temporal axes. The authors emphasize that the shape of the Universe did not affect the outcome: the separation of space and time turned out to be a local geometric property.
The Serbian scientists' modeling showed that the fundamental elements of space-time self-organize into the four-dimensional Universe we are familiar with in 85% of mathematical simulations, ScienceAlert writes.