Galileo vs the Vatican

www.theautomaticearth.com ^ | December 18, 2022 | Janet Daley

[Vaduz]

We have lived through a period of what would once have been the unthinkable suspension of basic freedoms: interventions by the state into personal life.

History repeating self by lesson not learned who you vote for means a lot but many never learn why.

Propaganda does work on to many

[Lonesome in Massachussets]

Galileo managed to get Copernicus placed on the Index almost 80 years after his death. The Roman church was more or less indifferent to Copernicus. (He was a Roman Catholic canon, an ecclesiastic lawyer, a rank equivalent to a monsignor.) Martin Luther was openly hostile to Heliocentrism in general and Copernicus in particular. In Starry Messenger, published in 1610, Galileo reported on his telescopic observations of the heavens. He made two crucial observations. First that Venus had phases, like the moon, and that the sequence of her phases was inconsistent with Venus orbiting the earth in a path inside the path of the sun. His observations demonstrated that Venus went into conjunction with the sun alternately between the earth and sun (inferior conjunction) and behind the sun (superior conjunction). This was inconsistent with Ptolemaic astronomy, but was consistent with Copernican and Keplerian models. His other critical observation was that the moon had mountains that cast shadows near the day-night terminator, and therefore has terrain like earth. It was therefore not a perfect sphere. He also famously observed that Jupiter had four galilean moons, visible with minimal optical aid, even a pair of 7 x 35 binoculars, or a small galilean telescope. He posited that the planets were, therefore, other worlds like earth. The publication of Starry Messenger caused no conflict with the church.

Although Kepler urged Galileo to validate his elliptical hypothesis, Galileo was a better experimenter and observer than analyst. In fact is it likely that Galileo could not calculate planetary positions using Copernican or Ptolemaic models. Owen Gingerich, in The Eye of Heaven: Ptolemy, Copernicus, Kepler shows convincingly that the Copernican model was no more accurate than the Ptolemaic model in predicting the position of planets or explaining their observed positions. Both were occasionally months off in predicting retrograde motion, and had roughly equal RMS errors in position. The advantage of the Ptolemaic model was that is was much simpler to use, requiring fewer calculations, and fewer parameters to model. The one advantage of the Copernican model was that it did not require the distance to the moon to change by a factor of two in the course of month, a phenomenon not observed, as the angular diameter of the moon only changes by few percent. A further perceived advantage of the Copernican model was that it resolved planetary motion into a combination of uniform circular motions, at the expense of simplicity. Ptolemy accounted for the effect of Kepler's second law by introduction of the much hated equant, which violated Aristotle's injunction that planetary motion must be resolved into uniform circular motions. This is an aesthetic consideration, not a scientific one. The Keplerian model was distinctly more accurate, but required solving a transcendental equation, at time when only a handful of mathematicians even knew how solve polynomial equations higher than quadratic.

Where Galileo got into trouble with the church is with the publication of Dialogue Concerning the Two Chief World Systems. Pope Urban VIII had been a friend of Galileo's and reviewed a draft of Dialogue. He asked a few questions about the treatment of tides. Galileo told him he would clarify those points in final draft. What Galileo did was put the Pope's questions in the mouth of the doltish character of Simplicio, and has the all-wise interlocutor Salviati dismissively swat them away. Unfortunately, the Pope's questions were reasonable, and Galileo's response was sophistry. Galileo also had a rural prelate provide the Imprimatur for the final draft, to avoid any Vatican interference. Kinda guy who could piss off the Pope.