100 years ago tomorrow, Einstein presented his field equations to the Prussian Academy of Sciences:

…So Einstein went back to the blackboard. And on Nov. 25, 1915, he set down the equation that rules the universe. As compact and mysterious as a Viking rune, it describes space-time as a kind of sagging mattress where matter and energy, like a heavy sleeper, distort the geometry of the cosmos to produce the effect we call gravity, obliging light beams as well as marbles and falling apples to follow curved paths through space.

This is the general theory of relativity. Its a standard trope in science writing to say that some theory or experiment transformed our understanding of space and time. General relativity really did.