The space-time from different matters point of view are different. At the same location, as Einstein assumed, it follows Special Relativity. The speed of matters can be any speed. But to make it easy, I compare three matters with three speed at the same location. One with no speed. From his stand point of view the radius is r_rest. The second matter is orbiting the gravity center. The second matter may not exist if there is Black Hole. The third matter moved from outside of the gravity field into the gravity field and has kinetic speed gainning from the gravity field. From their stand point of the view, the radius (Space) are not the same. Radius r_rest is the radius observed by the first matter without speed.