At radius 1: Acceleration Due to Gravity (ADG) is 16 times as strong as at radius 4. The object at radius 1 has 4 times so much KE and 4 times so little time to change the course (into a continues circular orbit) hence ADG must be 4*4 times so strong, = ADG 16 at radius 1,- to keep the object in circular motion. - So far so good..... BUT the point is:that the speed of the object at radius 1 is only double (*2) - even though that gravity ADG is *16 – WHY. It seems that there is a high price to pay for keeping the object in orbit, and that price is lower orbit speed. – Right ? - Or what's going on here ? Additional question According to GR gravity is caused to curvature of space, not to a force.. Or an object is not following an orbit because of a force or because of energy, but because of a property of space. According to Newtonian gravity , Gravity is a force. = F How is this possible? Are we ridding both a bull and a horse at the same time? Is gravity a force, - or is gravity not a force? And if gravity is a force, how can a force pop up from space ? - I mean without energy ?