True but general relativity allows non-inertial reference frames, in the same manner as special relativity allows using any inertial reference frame.

Here is a quote from Einstein that I've used before:

Einstein was making the point that there was no preferred reference frame. I doubt very much that he was in support of a Ptolemaic geocentric universe: that the earth IS the preferred reference frame, it is the center of a three dimensional universe, that all worlds and stars move about the earth, etc.

You could just as well make the same argument about Mars. That's it! Let's start the Arescentric universe model. Better yet - I'm the center of the universe. All bow before me, for all move about me, the immovable Van Rijn! Silly, sure, but I believe it is a logical extension of your argument.

It does say "the sun moves and the earth is at rest". That seems fairly clear.
Just for the record, I am not a geocentrist, so I don't think you should call my argument silly (or even a "logical extension" of it ). Other than quotes, my only "argument" in this thread was "True but general relativity allows non-inertial reference frames, in the same manner as special relativity allows using any inertial reference frame." Are you disagreeing with that?

[quote="A Thousand Pardons"]Apologies if I've wound anyone up (it really wasn't my intention, but I get the impression that I acheived it all the same. )

Also, please bear with me, as I said elsewhere I'm somewhat rusty w.r.t. GR, and I suffered the misfortune of having my copy of Schutz get stolen from a squat. (It's a long story. )

The reason for asking about the guy buzzing around in his rocket was hopefully to determine if this counted as an inertial frame in GR. (I don't think it is, but as I said, it is a long time since I did anything much with it.) Naively I tend to to think that if the inertial reference frame in which a body is at rest, is not constant (e.g. the infinite series of infinitesimal boosts required to accelerate an object in the kludged form of SR) then an object cannot be at rest. As I said, this is perhaps naive, but it seems to fit in with the intuitive notion of what static would imply. (Given the primary source for claims of a geocentric universe, it seems unlikely that their concept of geostasis is going to be particularly sophisticated.) Now the forces acting upon the earth are not only gravitational in nature. In my original argument I referred only to a gravitational interaction, however in the follow-up posts talking about potentially tiny net forces, my intention was to bring in the full panoply of interactions, ranging from electromagnetic to momentum exchange with the solar wind (hence my query about conservation of momentum), etc. Does this mean that there is no single inertial frame in which the earth is at rest?

I await to be shot down in flames.

general relativity allows non-inertial reference frames

I know. Newtonian mechanics allows non-inertial reference frames as well (hence the classical derivation of the Coriolis effect), though it gets the transformations wrong. You can even work within a non-inertial frame (using classical mechanics) within which the earth is at rest. If you also fix it so that the moon is stationary you end off with a simple derivation of the locations of the various earth moon Lagrange points.

How does GR account for the sudden change in angular velocity of the entire universe about the earth when an earthquake or something affects the earth's speed of rotation? The physics may work but doesn't it reuqire action at a distacne or an arbitrary change in angular velocity across the entire unvierse with no cause that just happen to coincide with events on earth?

Come to think of it, wouldn't a slowing earth mean that conservation of angular momentum is broken if you instead posit the whole universe slowing down about you?

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There are 10 types of people in the world. Those who understand ternary, those who don't, and those waiting for a bus.
If logic doesn't work, then surely it does.

That's a different use of the word "allow", but I'm sure you know that too.
Exactly. That's the difference, that it's "wrong"

I still sense that I'm winding you up, so I'll shut up on this topic until my new copy of Schutz arrives through my door. (It'll also prevent me from digging a deeper hole than I already have. )

I have that book. I haven't had a chance to read through it all yet though, only the first few chapters. What I read was really good though.

I have that book as well, somewhere around here I think. What is it you are looking for?

PS: Your spidey sense needs refurbishment.

It's not only my spidey sense that needs refurbishment, I need to give myself a 24 hour refresher with a decent text. Currently I'm holding two models in my mind. One has the principle of equivalence trading accelerations for uniform gravitational fields. On the other hand my mental picture of QFT (which is considerably fresher in my mind) is giving me forces mediated by the exchange of virtual particles, with momentum conservation at the vertices of the Feynam diagrams. (I also have a third image of two astronauts in orbit playing catch with a heavy ball, which isn't helping.)

The only way I'm going to get this straight in my head (which is what I need to do before I start running off down a potentially blind alley) is to revisit some of the mathematics.

I would imagine that that would be in a local inertial reference frame, possibly even local non-inertial reference frame, but it wouldn't have much applicability to the topic at hand, though, which would be more-ior-less global non-inertial reference frames.

In the same sentence, it also says as another part of the argument about reference frames, "the sun is at rest and the earth moves." Which appears to me to be an argument, in english (not math), for the concept that there is no preferred reference frame. Note that nowhere does it say "the earth is at rest and the sun moves about it" as the geocentrists believe.

However, if you want to discuss GR and reference frames, that's fine, but what you have not made clear is how it is applicable to the geocentric universe discussion.

I realize what they are saying.
If the earth is at rest, it'd only take less than 24 hours to find that the sun had moved about it. So, no, it does not say that, but I don't see how you can escape the implication.
In this thread, I was trying to answer a question that Fortis had asked in another thread, about general relativity. As I say above, I don't see how you can avoid the implication, so that it is applicable.

Exactly the same implication for any other point in the universe. And this is meaningful to the geocentric universe argument how ... ?

You mean any other point in the universe would go around the earth in 24 hours? I thought that was pretty much what "geocentrism" meant?

PS: No, now that I think about it, you must be saying that we can assume that Mars is not rotating also, correct? Still, you are accepting that it implies "the earth is at rest and the sun moves about it" then?

Does no one else think my questions were pertinent?

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There are 10 types of people in the world. Those who understand ternary, those who don't, and those waiting for a bus.
If logic doesn't work, then surely it does.

Are you thinking that it is not true that general relativity allows non-inertial reference frames? That general relativity somehow violates basic laws of physics? Is that it?