Work Step by Step
Bohr’s correspondence principle says that if a new theory (such as general relativity) is valid, it must give the same correct results as the old theory, i.e., it must correspond, in any area where the old theory (such as Newtonian gravity) has been verified. Strictly speaking, the correspondence principle was proposed for the overlap between quantum physics and classical physics, but we can extend its applicability, and broaden the definition. Einstein’s theory of gravitation overlaps, corresponds, and agrees with Newton’s theory for relatively weak gravitational fields. For strong fields, such as those near the sun, or near a black hole, Einstein’s theory gravity works perfectly (and diverges from Newton's theory). This is discussed on page 697.