Galileo did not have the scientific high ground in his assertion that heliocentrism is correct. Here is my analysis as an astrophysicists (not as a historian, so might get some things wrong):
- The orbital data that was available cannot distinguish between heliocentrism and geocentrism. This is exacerbated by Galileo’s insistence that the planetary orbits are circular instead of elliptical.
- If indeed the Earth moves, then parallax from distance stars should be observable. This measurement was only made a couple of centuries after Galileo’s death. Back then, it was thought that stars are much closer than they were (Galileo computed the distance to Mizar to be 300 AU, while modern measurements give a number that is ~17000 times further). If the stars were that close, parallax should be readily observable. Galileo had no answer to this missing parallax problem.
So, imagine yourself as a scientist in Galileo’s time. You were given two theories, where
- The current observation cannot distinguish between them.
- One of the theories have an observational hole in them.
And ask whether Galileo’s insistence that heliocentrism is definitely the correct theory is scientific or not.