Newtonian vs Einsteinian Gravity
There are two competing theories of gravity in the world of physics incompatible with one another. Redeeming Einstein by reserving for him the realm of the very large on galactic scales or near black holes in the similar manner how quantum mechanics dominates realm of the subatomic may too turn out as only a wishful thinking and a forced unnatural compromise. By the boolean logic one must check true, the other one false.The whole concept of a curved motion as "natural" motion started with the moon since it appears smaller then bigger then smaller again. Therefore some people presumed it must travel like a wave, and upon further Ptolemeic consideration an extra epicycle was thrown in