According to general theory of relativity gravity is not as a force but as a consequence of the curvature of space

time. But what 3D structure of gravity that is not clear.

Until the mid-nineteenth century the age-old idea of a cyclic or oscillating universe belonged to philosophical and

religious discourse, with little connection to the physical and astronomical sciences. It was only with the emergence of

thermodynamics, and even more so with the general theory of relativity, that it became possible to discuss the

hypothesis within a scientific context. - Helge Kragh