Has any of Newtons theories been proven inaccurate or incorrect?
Not necessarily ‘incorrect or inaccurate’ but rather as ‘incomplete’. I refer you to my answer on Einstein, but with respect to Newton, as a quick and dirty example to illustrate my answer: Newton’s laws of motion work within the confines of the universe as he understood it, but with more and more discoveries being made, the simple laws develop caveats… for example, Newton’s laws are based on an immutable universe. We now believe that the universe is expanding. The laws are then re-evaluated to see if they are impacted by this new info, or simply re-defined (such as basic laws of gravity modified to include the caveat of dependance on astral body mass and atmosphere etc.). But being ‘theories’ they remain neither proved nor disproved… just refined to accomodate more data.
