Originally Posted by **jaiii** Hello. I keep reading about how the space time curved so choose or make deductions from the rotating mass.
It is therefore only the geometry of space time or traveled by some physical reality? |

I'm sorry, I really can't make much sense out of the question. I'll give it my best guess.

The geometry of space-time gives us what are called "geodesics." A geodesic is the shortest distance between any two points in space-time. (Assuming you are just letting gravity take its course.) A geodesic, then, is the closest analogue to a "straight line" in a given metric space. For example, in the Cartesian xy plane in two dimensions a geodesic is, in fact, a straight line. But if we take our usual rubber sheet with a mass at the center we can easily see that the path an object takes is "curved" around the mass. The path can even curve around and meet itself as in the case of an orbit. The geodesics in this case are not what we would consider "straight," but still represent what we would call a straight line in that geometry.

I am, of course, being rather specific. To get a better idea, see

this. It's a little Math intensive, but with this sort of Mathematics that can't be helped.

If that doesn't answer your question, please try to re-write it and I'll take another shot at it.

-Dan