To refute the theory of gravity before it was established as a law, one would need to provide evidence that consistently contradicted the predictions made by gravitational theory. Here are a few types of evidence that could have been used:
-
Contradictory Observations: Empirical data showing that objects, when released in a gravitational field, do not fall towards the Earth (or gravitating bodies) at the expected rates (for example, demonstrating that heavier objects fall slower than lighter ones, contradicting Galileo's findings).
-
Non-Uniform Motion: Observations of celestial bodies moving in ways that cannot be explained by gravitational attraction, such as planets moving in orbits that deviate significantly from the elliptical paths predicted by Kepler's laws.
-
Unexpected Forces: Discovery of a new force or phenomenon that consistently counteracts gravitational attraction in predictable and repeatable ways (for example, if experiments showed that some objects inherently repel each other regardless of mass).
-
Inconsistencies in Tides and Orbital Mechanics: Evidence that tides or orbits could not be accounted for by gravitational interactions, leading to significant discrepancies in predictions based on gravitational theory.
-
Impacts from Relativity: If observations had shown that light was not affected by gravity (against predictions of General Relativity), or if massless particles exhibited behavior that contradicted gravitational influence.
-
Experimental Reproducibility: Repeated laboratory experiments that demonstrated gravitational effects (like mass attraction) could not be replicated under controlled conditions, suggesting that gravity was not a universal phenomenon.
-
Theoretical Models: Development of competing theories that could explain gravitational phenomena more accurately, such as a comprehensive model that could predict planetary motion without invoking gravity.
Ultimately, rigorous testing, observation, and the inability of observations to align with the gravitational model would have been necessary to refute it before it was universally accepted as a law. In science, theories are constantly subjected to scrutiny, and solid evidence against a prevailing theory can lead to its revision or rejection.