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Re: [Phys-l] Galileo was wrong



See below

Joseph J. Bellina, Jr. Ph.D.
Emeritus Professor of Physics
Co-Director
Northern Indiana Math Science and Engineering Collaborative
574-276-8294
inquirybellina@comcast.net


On Sep 20, 2010, at 6:41 PM, John Denker wrote:

On 09/20/2010 01:52 PM, Joseph Bellina wrote:
The problem for Galileo is that he had good arguments against the
Aristotlean geocentric model that was supported by the church, but he
did not have evidence that in fact the earth went around the sun, and
the Jesuit astronomers knew that. Foucault pendulum was 1851 or so,
long after this.

Huh????

Galileo may have been before Foucault, but he was after
Copernicus and after Kepler.

In addition to all the evidence from Copernicus and all
the evidence from Kepler, he had his own observations of
the phases of Venus ... and his own experimental and
theoretical mastery of the laws of motion.

There is no evidence from Copernicus, merely the conjecture that if one took a sun centered point of view, things might be simpler. Indeed when he waved his hands about it, it was, the major epicycle was removed. But when he looked in detail, the piece he objected to most, the equant had to be retained to fit the earth centered model to the data. That was not corrected until Kepler conjectured that the paths were not circles.

He observations of the phases of Venus suggested that Venus was orbiting the sun, but of course in a Tychonian model that is what you expect. The earth at the center, the sun orbiting the earth and all the other planets orbiting the surn. It was a good argument against the Aristotleans as was the evidence of changes on the moon as he wrote in the Message from the Stars.

Mastery of laws of motion are all conjectures, mere mathematics, not evidence of physical reality. The church was more than willing to say that we could think of things as earth centered for the convenience of mathematics, and of course an improved calendar system, but what evidence was there that the earth actually moved. Such evidence came centuries later, and some can still be disputed.

If Galileo had lacked convincing arguments, he would
have been ignored. They took strong action against him
precisely because they knew he had tons of evidence.
They knew his books understated what he actually knew.

They knew he did not. G was a crusty only Italian who rubbed the pope's nose in the dirt, but didn't have the data to support his position.

Stillman Drake is always an interesting and authoritative read.

Yes indeed.

I think you will find Drake in agreement with my account.

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