Science Forums 2

[Roberto]

Our present understanding of gravity suggests that it is only a manifestation of spacetime curvature. Mass curves the space around it. The mechanism is unclear, but it happens.

According to General Relativity, a body subject only to gravitation, simply describes a path in the space that corresponds to the shortest distance between two points of spacetime. When there is no body in the neighborhoods, it describes a straight line at constant velocity. When a body happens to be next, the curvature of spacetime makes the shortest path between to points to be distorted and the moving body will simply follow this distortion.

Pretty simple, isn't it? This is equivalent to say that all bodies subject only to gravity travel in geodesics in the spacetime. Matter curves spacetime and distort these geodesics from a straight line to other curves, depending on the distribution of matter.