Dear PF Forum, I have a confusion about gravity. And frankly I don't know if this question belongs to this sub forum (cosmology, general physic?). Gravity attracts object - Newton Gravity curves space time - Einstein. Why we revolve around a massive object? Because that massive object curves space and we try to travel straight? So we revolve that massive object because that object curve space around it and we think that the curve is straight line? But what if we don't travel. What if we just sit still and there's a massive object coming toward us. Would we still revolve that object once we are in its gravitational field? I think we are ALWAYS in its gravitational field no matter how far that object but its force (if we can call graviti, force) would be very weak. A: So from our point of view. Whoaa, there's a big object coming toward us, but why would we revolve around it. We just sit still right? B: From that massive object point of view Hey, there's a little thing coming toward me, well once it is in my gravitational field, it will revolve around me. So no matter how the small object always revolves the bigger object right? And as I read somewhere the bigger object also revolves that small object but in a less curve. ================================= So my conclusion is this. In space time A: Do we always move in time? I think so, we are getting older aren't we? B: Do we ALWAYS MOVE in space? Does everything in this universe always move in space? C: If B is true, is that why every object always revolves other object either bigger or smaller, because everything ALWAYS MOVE in space? Thank you very much.