Space Time Curvature

General relativity generalizes special relativity and refines newton s law of universal gravitation providing a unified description of gravity as a geometric property of space and time or four dimensional spacetime.
Space time curvature. Space is space and time is time and there is no curvature. In particular the curvature of spacetime is directly related to the energy and momentum of whatever matter and radiation are present. The space time curvature is a key concept in albert einstein s theory of relativity. This does not mean that four dimensional notation is not useful.
In the absence of gravity those paths look like the straight lines we re all used to. In the absence of an external force objects travel along the straightest possible paths geodesics through spacetime. That my friends is the gravitational force. If space time exists everywhere including the mass itself in this case a mass can t curve space time because all space time to be curved is inside it.
In 1 1 dimensional minkowski spacetime having one temporal and one spatial dimension the points at some constant spacetime interval away from the origin using the minkowski metric form curves given by the two equations. What it means though is that a falling object follows a path called a geodesic. We still try it. What exactly is meant by the concept of space time curvature is not so easy to explain.
Faster things curve less. But in the presence of mass they can look very curved. Now of course it involves time as well as space so it s more complex than the rubber sheet thing. That s the curvature of space time.
The answer in quantum field theory is simple.