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Dr. Barr:

Are you basically saying you accept general relativity, but not its strong principle?

How do you explain this statement from Einstein with no relativity of rotation? Is our argument over semantics?:

"The struggle, so violent in the early days of science, between the views of Ptolemy and Copernicus would then be quite meaningless. Either CS could be used with equal justification. The two sentences, 'the sun is at rest and the earth moves,' or 'the sun moves and the earth is at rest,' would simply mean two different conventions concerning two different CS." -- Einstein and Infeld, The Evolution of Physics, p.212 (p.248 in original 1938 ed.)

CS obviously = coordinate systems

How about:

Max Born in his famous book,"Einstein's Theory of Relativity",Dover Publications,1962, pgs 344 & 345 says:

"...Thus we may return to Ptolemy's point of view of a 'motionless earth'...One has to show that the transformed metric can be regarded as produced according to Einstein's field equations, by distant rotating masses. This has been done by Thirring. He calculated a field due to a rotating, hollow, thick-walled sphere and proved that inside the cavity it behaved as though there were centrifugal and other inertial forces usually attributed to absolute space.

Thus from Einstein's point of view, Ptolemy and Corpenicus are equally right."




Mark Wyatt

Samuel Barr says:"All experts in General Relativity would agree that in GR acceleration is an absolute concept."

Another way of putting the same point is to say that, in Newtonian mechanics and special relativity, rotation is “absolute” because the transformations between inertial frames (Galilean or Lorentzian) preserve rotational states. Thus the “absoluteness” of rotation arises precisely from singling out one type of frame, by one type of transformation, instead of allowing arbitrary transformations and arbitrary frames. Einstein held that this epistemological insight had a natural mathematical representation in the principle of general covariance, or the principle that the laws of nature are to be invariant under arbitrary coordinate transformations. More precisely, what this means is that coordinate transformations are no longer required (as in the affine spaces of Newtonian mechanics and special relativity) to take straight lines to straight lines, but only to preserve the smoothness of curves (i.e. their differentiability). The general theory of relativity was intended to be a generally covariant account of spacetime, and its general covariance was intended to express the general relativity of motion. And the theory came into being because Einstein perceived a deep connection between this project and that of finding a relativistic theory of gravitation.

http://plato.stanford.edu/entries/spacetime-iframes/

Mark Wyatt

Samuel M Barr says:

"you are absolutely wrong, Mark! All experts in General Relativity would agree that in GR acceleration is an absolute concept. The concept of an "inertial frame" is a crucial one in GR. An inertial frame is a non-accelerating frame. One can tell by local measurements whether one is in an inertial frame or not. This is non-controversial. Anyone who knows GR understands this. It is true that Einstein was led to GR by Machian ideas, and according to Mach's ideas acceleration is relative. But it is generally agreed by that the theory Einstein actually came up with is NOT Machian. Though he was inspired by Mach's ideas, Einstein's theory does not actually realize Mach's principle of the relativity of acceleration. "

An inertial frame is a non-accelerating one in general relativity (or any other theory), yes. BUT YOU CAN MAKE ANY FRAME IN THE UNIVERSE A REFERENCE FRAME. and the rest of the universe will accelerate around it and account for the forces which makes the frame you chose a fixed frame. This is the general principle of relativity.

General relativity describes the system (in this case the universe) relative to the rest of the universe from the perspective of the reference frame. Thus relativity.


Mark Wyatt

The simplest explanation is the neo-Tychonic model: Earth stable at center, universe rotates, holding earth stable at center (expalined in the book). Sun revolves with the universe (though has a small difference in velocity), planets orbit the sun with elliptical orbits (earth is not a planet in this case). The stars revolution is centered on the sun.

This is an exact geocemetric inversion of heliocentrism.

Other more complex explanations are based on aether, aether flow, and abberation.

Mark Wyatt

I never got to finish that previous conversation.Here it is:

Sir, I am afriad you don't understand GR correctly. While Einstein was indeed influenced by Mach's ideas, GR is not really a Machian theory, though it predicts some effects that are reminiscent of Machian ideas (like dragging of inertial frames). One can find some books that say that GR is Machian, but the general consensus is that it is not. In GR, uniform motion is relative, but accelerated motion is absolute --- just as in Newtonian physics. The question of whether something is rotating or not is an ABSOLUTE question with one and only one correct answer. Yes, one can go to a frame in which a rotating object looks like it is not rotating --- however, such a frame is not an inertial frame; more specificly, it is a rotating frame. And one can tell that it is so by looking at the "fictitious forces" that appear in that frame. It is absurd to say that the whole universe could be rotating about an axis that goes through the earth. Distant stars could only be kept in circular orbits about such an axis by some centripital force directed toward that axis. Here the people like Sungenis will babble about dragging of inertial frames. They say that the distant matter going around will drag the stars around the axis. Not so. Not least of the problems with this idea is that one cannot write down a global rotating coordinate system, since the time coordinate lines would become superluminal at some finite (and not so large) distance. To put it another way, if all the stars go around the earth every 24 hours, then stars more than a light-year away would be going faster than light. But all this is nonsense anyway. Anyone who has a solid grasp of GR knows that in it accelerated motion is an ABSOLUTE concept. Finally, let me say that I actually do research in areas that require GR. I have refereed papers for journals such as Classical and Quantum Gravity. As I said, I teach GR at the graduate level --- do you?



17 posted on 10/11/2005 6:58:42 AM PDT by smpb (smb)

---

I agree, there is some controversy as to whether GR is Machian. I should have stated that it contained Einstein's interpertation of Mach.

Still in GR there are no fictitous forces in rotation. They become real forces as described by Thirring, Barbour and Berlotti, Bondi, etc. Einstein invented GR specifically so he could relativize rotation (a shortcoming of SR). When you reduce to the approximation of a Post-Newtonian formulation, then you are more SR-like, but as a general principle, rotation is relative in GR.

As to the point at which velocities of the stars become superluminal, this is the Schwartzchild radius, and Bondi has demonstrated that a shell of matter at this radius represents the effect of the rest of the universe. This lends support to Thirring, Barbour Berlotti, etc.

This also lends support to the ideas that aether theory can reproduce many relativistic effects (i.e, frame dragging). It tends to reduce GR to a more local action as it is usually described. Aether theories, especially with graviton type gravity tend to be more local in action also, while Mach's principle is more universal. Never the less, the matter at the farther reaches of the universe do have an effect at the earth, it is just a matter of how to represent it.

Mark

RobbyS says: "The Church condemned him because of its attachment to Aristotle, not Christ. But Galileo's personal arrogance play ed a huge role."

That is a theory. That is not what the Church itself said:

Whereas you, Galileo, son of the late Vincenzo Galilei, Florentine, aged seventy years, were in the year 1615 denounced to this Holy Office for holding as true the false doctrine taught by some that the Sun is the centre of the world and immovable and that the Earth moves, and also with a diurnal motion; for having disciples... ...and for replying to the objections from the Holy Scriptures, which from time to time were urged against it, by glossing the said Scriptures according to your own meaning: and whereas there was thereupon produced the copy of a document in the form of a letter, purporting to be written by you to one formerly your disciple, and in this divers propositions are set forth, following the position of Copernicus, which are contrary to the true sense and authority of Holy Scriptures:

The Sacred Tribunal being therefore of intention to proceed against the disorder and mischief thence resulting, which went on increasing to the prejudice of the Sacred Faith, by command of His Highness and of the Most Eminent Lords Cardinals of this supreme and universal Inquisition, the two propositions of the stability of the Sun and the motion of the Earth were by the theological Qualifiers qualified as follows:

The proposition that the Sun is the centre of the world and does not move from its place is absurd and false philosophically and formally heretical, because it is expressly contrary to the Holy Scripture.

The proposition that the Earth is not the centre of the world and immovable but that it moves, and also with a diurnal motion, is equally absurd and false philosophically and theologically considered at least erroneous in faith.

...We say, pronounce, sentence and declare that you, the said Galileo, by reason of the matters adduced in trial, and by you confessed as above, have rendered yourself in the judgement of the Holy Office vehemently suspect of heresy, namely, of having believed and held the doctrine – which is false and contrary to the sacred and divine Scriptures – that the Sun is the centre of the world and does not move from east to west and that the Earth moves and is not the centre of the world;...


Mark

Dr. Barr:

I remember you stating in a previous post (last year) that rotation is absolute in general relativity. This is factually untrue. It is absolute in special relativity. Einstein invented general relativity to solve this issue (relativity of rotation).

We can all make errors.

Mark

Are you the author of "Modern Science, Ancient Religion"?

I disagree on Dr. Bennett. His chapter 12 is a pretty significant piece of work.

Mark

Relative motion. What the scientists believe to be the true reality is not important. As long as the calculations are done right, they will hit the target. Both models heliocentric, geocentric) properly done will give the right answer.

This is explained in the book.

Many of those targets (near earth) were hit using trajectories calculated from geocentric reference frames.

Mark

Perhaps, so, but it is the Church who ultimately condemned him. If you read Geocentrism 101, Part III and the supplement on my blog (where the article is) I go through a lot of detail on that.

Mark

If you had read the book, I think you would at least be open to it. I have studied this for a few years before the book came out, but it is clear that we have not demonstrated movement of the earth.

Robert Sungenis shows pretty clearly that as science ran into observations that would indicate earth at center, they modified the science rather than accepting geocentrism. He also shows pretty clearly that no one has questioned [the basic premise of] heliocentrism since Copernicus. True there were some key observations (i.e., parallax in the early 19th century), but there are geocentric explanations for parallax.

Over all heliocentrism (or its modern variant acentrism with barycentric solar system) is just accepted as fact, and science is tailored to say it is the case, rather than (as it is presented to the public) science is searching for the truth.

Think about it-how could earth end up in the center? There is only one way I can think of: God willed it so.

Science cannot tolerate such a conclusion.

Mark

I cut this from the blog, but it is a slightly outdated version. Nothing significant, just the current version reads a little easier.

MArk

I have added a commentary:

http://veritas-catholic.blogspot.com/2006/01/commentary-on-fatima-soliloquy.html

Mark Wyatt
www.veritas-catholic.blogspot.com

What think ye?

Theo:Of course there is! Is called parallax. The stars "shift" position against the background as the Earth moves around the Sun. Of course, this only can be measured on the closest stars. The farther off a star is, the more difficult it gets to measure its parallax."

Parallax can be explained in geocentric theory, also. Sorry.
See Part I of Geocentricity 101.

Mark Wyatt
www.veritas-catholic.blogspot.com

Teofilo: "...your quaint attempt to restore an updated view of Ptolemy..."

Actually, the view is closer to a modern Tychonian view than a Ptolemaic one. In the modern Tychonic, the earth is stationary in the center of the universe. The sun and universe revolve around the the earth. The planets (earth not being one) orbit the sun with approximately LKeplerian type orbits (plus all other pertubations, etc.).

In the Ptolemaic view, all the planets directly orbited the earth with epicycles.

Mark Wyatt
www.veritas-catholic.blogspot.com