The Three Sillies illustrated by Arthur Rackham, as found on Project Gutenberg.
Every once in a while, I come across the claim by some well-intentioned Catholic that Sacred Tradition demands that we adopt a geocentric model. I'm not really sure what drives this kind of misconception; it may be an honest mistake about what the point of Church Teaching is, or it may be the same kind of thrill with being one of the few "in the know" that has led me to compare cryptozoology with pagan mystery religions. Periodically these claims are disposed of by Catholic apologists, and it is not my intention to deal with the whole issue here.
Instead, I would like to deal with a more subtle argument that is occasionally tossed out by geocentrists. Many of them have enough education to know that Einstein's General Theory of Relativity allows us to correctly describe the mechanics of the universe using essentially any coordinate system, including coordinate systems in which the Earth is non-rotating, stationary, and at the center. Nature is satisfied with such a coordinate system. If that coordinate system is as good as any other, surely preference should be given to the one used by the Church Fathers?
Of course, this misses the fact that Relativity specifically denies that the idea of a center is physically meaningful, and it is only physically meaningful distinctions that are in dispute. No one will deny that the Earth is the center of the baseball universe, for example. But is it true that just because it is possible to make correct physical descriptions in any coordinate system, no coordinate system can be said to be "better" than another?
The answers to a surprising number of basic questions can be found in folk tales. The one of relevance here is an English folk tale called, "The Three Sillies". Please read the whole story, but the passage that most pertains to this case is as follows.
And the inn was so full that he had to share a room with another traveler. Now his room-fellow proved quite a pleasant fellow, and they forgathered, and each slept well in his bed.Although the stranger managed to eventually get his pants on each morning, the reader (or listener) is supposed to understand immediately that this is the wrong way to put on pants.
But next morning, when they were dressing, what does the stranger do but carefully hang his breeches on the knobs of the tallboy!
"What are you doing?" asks young squire.
"I'm putting on my breeches," says the stranger; and with that he goes to the other end of the room, takes a little run, and tried to jump into the breeches.
But he didn't succeed, so he took another run and another try, and another and another and another, until he got quite hot and flustered, as the old woman had got over her cow that wouldn't go up the ladder. And all the time young squire was laughing fit to split, for never in his life did he see anything so comical.
Then the stranger stopped a while and mopped his face with his handkerchief, for he was all in a sweat. "It's very well laughing," says he, "but breeches are the most awkwardest things to get into that ever were. It takes me the best part of an hour every morning before I get them on. How do you manage yours?"
Then young squire showed him, as well as he could for laughing, how to put on his breeches, and the stranger was ever so grateful and said he never should have thought of that way.
"So that," quoth young squire to himself, "is a second bigger silly."
What the geocentrists would have us do is just as silly. Most mechanics does not really require Relativity; usually Newton's Laws are sufficient, and they can be taught to students with no more math than algebra and trigonometry.
An example would be the trajectory of a satellite in a circular polar orbit. For this, we can choose a coordinate system in which the Earth is stationary, but we still need to allow the Earth to rotate under the satellite. Everything is easy to explain; the satellite is in uniform circular motion, and its centripetal force is supplied by gravity as specified by Newton's Law of Universal Gravitation.
If we maintain that the Earth does not rotate, though, the eastward rotation of the Earth will have to be explained as a westward force on the satellite, a force that varies with latitude and is hard to justify in simple terms. The real justification comes from a relativistic phenomenon called frame-dragging, in which the motion of a massive body "drags" the inertial reference frame with it. In sane coordinate systems, this is hard to measure except near a massive, exotic object like a black hole or neutron star. A very sensitive experiment, Gravity Probe B, was required to see this effect from the rotation of the Earth. To calculate the relativistic forces from first principles requires coupled partial differential equations of tensors -- higher math than most people will ever see, let alone master.
The final answers for what will be observed are, of course, identical, just as the final result of putting on their pants was identical for the young man and the stranger. Just as trying to jump into the pants is the wrong way to put on pants, though, the geocentric approach is the wrong way to do physics. To top it off, the people with the attachment to the geocentric model always prove to have never even attempted to solve physics problems in what they insist is the uniquely correct way.