The Allais effect -- Changing our views on gravity and how it works.

In 1954 Maurice Allais, a French economist who would go on to win the Nobel prize, decided to observe and record the movements of a pendulum over a period of 30 days. Simultaneously, during one of his observations, a solar eclipse took place. Just as the moon passed between the sun and the earth, the pendulum began moving faster that expected. Now known as the "Allais effect", it contradicts Einstein's theory of General Relativity - The modern …

…short for MOdified Newtonian Dynamics) which suggests that at extremely low accelerations, gravity gets slightly stronger. An even stranger theory is that the force of gravity is different at different directions. Most physicists dislike that one. It uses the concept of 'frames of reference', in which movement, acceleration, and so on are not uniform in all directions. But it was a similarly radical idea which put the "relativity" into relativity theory in the first place...