As learned Europeans began accepting the Copernican view of the earth revolving around the sun and rotating on its axis, was there a transition period in which some bought into the rotation part but still considered Earth to be the center of the planetary motions?
Yes, the Tychonic system had a rotating but central Earth.
That is awesome. Even more awesomier, because my son had some Mario/Nintendo kind of music playing on his computer while I was looking at it.
That link shows the sun at the center. The Brahe system is this
Sorry, you have to click the “Tyconic” button in the lower right of the screen. Guess it defaults to Copernican.
Wow, an answer from one of Copernicus’s buds! Thanks!
Galileo’s bud (actually a fictitious nemesis).
That link is brilliant!
Tycho’s system came after Copernicus’, though. It was a hybrid intended to capture the scientific virtues of the Copernican system, while maintaining the philosophic appeal of having the Earth central. The system prior to Copernicus was the Ptolemaic system. And I think that the Ptolemaic system did, in fact, accept a rotating Earth (because otherwise, one would be forced to conclude that the stars move ludicrously fast).
Am I mistaken in believing that the Tychoian system is more or less the way we actually see things moving around in space? I ask this because, obviously our telescopes and whatnot are on the earth, and so it does appear that the planets get way closer and the way farther away as you observe them over time. It must take some effort (or it did back before computers) to plot observations relative to the sun when all we have are observations relative to something else. (Example: If you go with trace Jupiter on Tycho-view, it makes a kind of circular spiral.)
Very nice. Watching the paths traced by the planets in the Tychonic model made a light go on with regards to how Ptolemaic epicycles were supposed to work, too.
Sorry, misspoke. I stand corrected.
If I understand correctly, Ptolemy had the earth stationary with the outermost sphere explaining the daily rotation. Copernicus eliminated that sphere and the sun’s epicycle, but kept all the other epicycles and mechanisms to explain the non-circular and non-planar orbits. I had not heard of the Tychonic system, but I guess it just eliminated the outer sphere.
IIRC, the Copernican system still had errors because like Ptolemy he insisted on circular orbits. The big advantage with Copernicus was that it greatly reduced the number of epicycles needed from something like 19 to 11.
All of the systems are more or less how we see things, depending on how accurately we see them. The development of the telescope is what led to the Copernican and Tychoian models. Even special relativity was confirmed by making highly accurate observations of Mercury.
Copernicus actually needed more epicycles then Ptolemy, for the reason you say, he assumed all motions had to be made of circles instead of ellipses. And it actually wasn’t as good at fitting observations as Ptolemey’s system.
[rambling]The main reason Copernicus proposed and others supported his system, at least early on, was because he subscribed to a philosophical principal that all celestial motions should be made of constant circular motions, and Ptolemey needed a third type of motion in his system that wasn’t a uniform circle.
I always find it interesting that the idea that Copernicus was motivated by modern scientific concerns of trying to find the simplest possible model to fit observations is so persistent, even though his model was neither simplifier or empirically superior. In reality, his actual motivation was to perserve an idea that today is recognized as false, but there seems to be a really strong desire amongst pop-sci writers to have him be an early scientist in the modern sense, motivated by the kind of things that motivate modern scientists.[/rambling]
Both models predate the telescope, though the telescope would eventually help support them.
I am sorry to rain on your parade, but this is FALSE. The Earth did not rotate (or move in any way) in the Tychonic system, and the fact that it appears to rotate in that animation is merely evidence of the carelessness (or ignorance) of the animator.*
The whole point of the Tychonic system was to keep the Earth stationary (in accord with intuition, the Bible, and Tycho’s inability to find any evidence for the stellar parallax that a moving Earth, orbiting or rotating, should cause**) whilst retaining the mathematical and predictive advantages of the Copernican system. For Tycho, day and night, and the apparent diurnal rotation of the stars, were accounted for in the traditional way, by having both the Sun and the sphere of “fixed stars” in orbit around the stationary Earth. However, it differs from the traditional Aristotelian/Ptolemaic system in that it has the orbits of the other planets centered on the moving Sun rather than on the stationary Earth.
The correct answer to EdwardLost’s OP is “No”. There were no transitional systems of that type. Tycho’s system is a transitional one, but of a different type to that envisaged in the OP.
In fact, if anything, people would have found the idea of a rotating Earth more difficult to accept than the idea of an Earth rotating around the Sun. It was assumed (incorrectly, but not unreasonably) that if the Earth was rotating, we would be able to feel the motion, that there wold be a strong, continuous wind blowing from east to west, that objects dropped from a height would fall towards the west, etc. Much of Galileo’s Dialogue of the Two Great World Systems (the book that got him in trouble) is devoted to refuting this very intuitive argument against heliocentrism, and Galileo had to revolutionize the science of mechanics (and, in effect, invent the concept of inertial motion) in order to make his case!
Furthermore, it was Biblical passages that appeared to imply that the Earth is not rotating, but that the Sun is rotating around it, that became the pretext (not, I think, the real reason) for Galileo’s trial and condemnation by the Catholic authorities. These passages (certainly what was recognized as the most important one, in the Book of Joshua) do not specifically imply that the Earth is at the center of the universe, or even that it is stationary, just that the alternation of day and night is caused but the Sun orbiting the Earth.
It is also worth noting that Jesuit astronomers in Galileo’s time already recognized the predictive advantages of the Copernican system, but they avoided the ‘heretical’ implications of a rotating Earth by adopting the Tychonic system. They could not have done that if Tycho had taught that the Earth is rotating.
¬¬¬¬¬¬¬¬
*The animation also shows the asteroid belts, and Uranus and Neptune, all, of course, unknown in Tycho’s time. It also fails to rotate the outer sphere of “fixed stars” as it should (showing the stars as a fixed background rather than a moving encircling sphere), and it leaves out all the epicycles, eccentric points, etc. that Copernicus used, and that Tycho would still need, to make the system a useful, predictive mathematical model. However, in this last respect it is true to Tycho’s own practice. He was aware that, for doing mathematical astronomy, it was easier to use the straight Copernican model. Tycho’s aim was simply to show that, by holding the Earth instead of the Sun as the stationary central point, you could justify using Copernicus’ math without having to buy into the counterintuitive (and, as he thought, empirically refuted) notion of a moving Earth.
**In fact this stellar parallax does exist, it is just a much smaller effect than anyone in Tycho’s time expected it to be, because the stars are very much further away than anyone in those times ever imagined. Thus, although Tycho’s measurements were hugely more accurate than any ever made before, they were still not accurate enough to reveal the very small effect. For him, knowing that his measurements were the best ever, this failure amounted to excellent evidence that the Earth is not moving.
ETA: Actually, on second thoughts, I do not think a rotating but unmoving Earth would have been expected to produce a stellar parallax effect. However, the rest of what I said stands. Tycho has plenty of other reasons for thinking that the Earth does not rotate.
Nitpick: it was the general theory of relativity, which provided the mechanics to describe space distorted by the presence of mass-energy, i.e. gravitation, that was confirmed by observations of the anomalous precession of Mercury. Special relativity, which should properly be regarded as an approximation that applies only in inertial reference frames and with locally flat space-time topography, was confirmed (and in face was developed to explain) the invariance of light regardless of the direction of motion against a presumed fixed medium (the luminiferous aether).
Stranger
Nah, the animator is just using a loose nomenclature. Your right the system originally proposed by Tycho had a fully stationary Earth, but it also had several other inaccuracies. The geo-heliocentric models that most astronomers adopted at the time were credited to Tycho and called Tychonic systems, but they were really first proposed by Nicholas Bar (“Ursus”), who also had an Earth with a daily rotation. For whatever reason, though (probably because of the prominence of Tycho’s observatory) its pretty rare to see the term Ursic system, and while the geo-heliocentric system that was popular during Gallileo and Keplar’s time had daily rotation and was closer to Ursus’s system, they usually get lumped in as “Tychonic”.
So to reiterate, there were indeed popular systems that accepted rotation but not revolution.