> The explanation of why gravity is only positive is a complex one, but physicists believe it's almost axiomatic Isn't that a consequence of relativity, the sp

> The explanation of why gravity is only positive is a complex one, but physicists believe it's almost axiomatic Isn't that a consequence of relativity, the speed of light being constant by definition? I'm not sure that makes any sense, though, what is the physical unit of gravity N? Jf you mean classical mechanics, than there has to be a negative counterforce by the three axioms of newtonian mechanics and it's just a question of frame of reference. BTW: Stress on ax-iomatic, as in axis?!