The linked story mentions that Galileo noted that the dot we now call "Neptune" had, in fact, moved.

His recognition of that is pretty close to saying it was a planet. Lights that did not move = stars. Lights that did move = planets. The only problem was that he couldn't resolve it to a sphere, like the other planets.

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"Barbarism is the natural state of mankind. Civilization is unnatural. It is a whim of circumstance. And barbarism must always ultimately triumph" -- Conan