Einstein's statement that general relativity is more correct than Newtonian mechanics when it comes to gravity is based on his groundbreaking theory of general relativity, which he published in 1915. There are a few key reasons why Einstein made this claim:
Consistency with the Theory of Special Relativity: Einstein's theory of special relativity, published in 1905, revolutionized our understanding of space and time. It introduced the idea that the laws of physics should be the same for all observers in inertial reference frames. Newtonian mechanics, on the other hand, does not account for the effects of relativity. General relativity, however, is consistent with special relativity and provides a more comprehensive framework that encompasses the effects of gravity.
Modification of Spacetime Geometry: According to general relativity, gravity is not simply a force acting between objects as Newtonian mechanics suggests. Instead, Einstein proposed that gravity arises due to the curvature of spacetime caused by the presence of mass and energy. In this view, massive objects like planets and stars cause spacetime to curve, and other objects move along the resulting curved paths. This concept of spacetime curvature provides a more accurate description of the behavior of gravity than the concept of a gravitational force in Newtonian mechanics.
Predictions and Experimental Confirmation: General relativity makes several predictions that differ from those of Newtonian mechanics, particularly in extreme conditions involving strong gravitational fields or high velocities. For example, general relativity predicts the bending of light by gravity, the precession of Mercury's orbit, the gravitational time dilation (time dilation due to differences in gravitational potential), and the existence of black holes. These predictions have been observed and confirmed through numerous experiments and observations, providing strong evidence in favor of general relativity's accuracy.
Overall, Einstein's claim that general relativity is more correct than Newtonian mechanics on gravity stems from the theory's consistency with special relativity, its explanation of gravity as spacetime curvature, and its successful predictions and experimental confirmations that go beyond what Newtonian mechanics can account for.