  One of the most fundamental questions of modern physics is the nature of
spacetime. There are various propositions on the table, as the grand unified
theory, quantum gravity, supersymmetry, string and superstring theories, and M
theory. However, none of these propositions is able to consistently explain
what matter is and how matter interacts by describing at the same time
electromagnetism, relativity, gravitation, quantum physics and observed
elementary particles. Here it is proposed that spacetime is an isotropic
Newtonian 3D lattice, and that its topological defects, namely diverse
dislocations and disclination loops, are the fundamental building blocks of
ordinary matter. We find, for an isotropic lattice obeying Newton laws and with
specific assumptions on its elastic properties, that the macroscopic behaviour
of this lattice and of its topological defects displays all known physics,
unifying electromagnetism, relativity, gravitation and quantum physics, and
resolving some longstanding questions of modern cosmology. Moreover, studying
various possible microscopic structures of the Newton's lattice, for example
assuming lattice axial symmetry, represented by a colored cubic 3D lattice, we
show that one can possibly identify a lattice structure whose topological
defect loops coincide with the complex zoology of elementary particles, opening
a promising field of research.
