Question for Alec (hecd2) re: Gary Hoge's Geocentric assertions

Hi Alec,

I have cooperated with you and answered a lot of questions. I admit freely that I am not a cosmologist (no supries, eh), but I have studied a lot of these issues.

Now, you have yet to respond to the questions I have asked. Will you do me the favor of offering your opinion on these questions:

  1. If a fixed earth coordinate transformation is made, and a solution for the force field at and near the earth were calculated using Einstein’s general relativity, would or would not the rotating distant cosmic masses produce forces at and near the earth analogous to those which describe the orbit of geosynchronous orbits of satellites using Newtonian mechanics and a rotating earth. Please consider Einstein’s equivalency principle.

  2. Would the fact that one can describe geosynchronous orbits of satellites using Newtonian mechanics in and of itself disprove Geocentrism?

  3. Would the fact that one can describe geosynchronous orbits of satellites using Newtonian mechanics automatically mean that analogous forces would not exist in the fixed earth case?

  4. If one were to claim that the fact that one could calculate the orbits of geosynchromous satellites using Newtonian mechanics led to the disproof of Geocentrism, would one not need to state that it also disproved Einstein’s genral relativity, or at least the (strong) equivalence principle?

Thank You

[quote=trth_skr]Hi Alec,

I have cooperated with you and answered a lot of questions. I admit freely that I am not a cosmologist (no supries, eh), but I have studied a lot of these issues.

Now, you have yet to respond to the questions I have asked. Will you do me the favor of offering your opinion on these questions:

  1. If a fixed earth coordinate transformation is made, and a solution for the force field at and near the earth were calculated using Einstein’s general relativity, would or would not the rotating distant cosmic masses produce forces at and near the earth analogous to those which describe the orbit of geosynchronous orbits of satellites using Newtonian mechanics and a rotating earth. Please consider Einstein’s equivalency principle.

  2. Would the fact that one can describe geosynchronous orbits of satellites using Newtonian mechanics in and of itself disprove Geocentrism?

  3. Would the fact that one can describe geosynchronous orbits of satellites using Newtonian mechanics automatically mean that analogous forces would not exist in the fixed earth case?

  4. If one were to claim that the fact that one could calculate the orbits of geosynchromous satellites using Newtonian mechanics led to the disproof of Geocentrism, would one not need to state that it also disproved Einstein’s genral relativity, or at least the (strong) equivalence principle?

Thank You
[/quote]

trth_skr,

If I may, I’d like to step in and try answering some of your questions. Like you, I am no cosmologist (although I own a copy of Misner, Thorne, and Wheeler and have dug into it several times–but I lay no claim to understanding it thoroughly). I am an aerospace engineer with a fairly good grasp of mathematics and coordinate transformations.

  1. If a fixed earth coordinate transformation is made, there is no need to invoke general relativity. In the fixed-earth coordinate system there will be terms that allow for a geosynchronous satellite to follow a figure-eight orbit over a small region of the earth around its equator. Most physicists call them centripetal acceleration terms; followers of the geostationary theory will ascribe these terms to “the rotating distant cosmic masses.”

  2. The fact that one can use Newtonian mechanics does not in and of itself disprove Geocentricism. I stated in another thread that Geocentricism is simply a coordinate transformation and not a separate theory in and of itself. This coordinate transformation will introduce all sorts of wild and weird acceleration terms (I called them “fictitious forces,” I think) and as such is not as useful as the Copernican theory (modified to allow for the sun’s revolution about the galactic center and so on), whose equations are simpler. So Geocentricism is not wrong per se, it’s just not very useful. “The world really does revolve around engineers, because they get to pick the coordinate system.”

  3. I’m not sure what you mean by “analogous forces.” Please explain.

  4. I think this question is moot, since Geocentricism (at least the coordinate transformation version of it) is not disprovable. Even if it were, I don’t know enough about the relation between Geocentricism and general relativity to answer this question.

Now, if you would, please step over to the Non-Rigid Earth thread and answer my questions.

  • Liberian

[quote=Liberian]trth_skr,

If I may, I’d like to step in and try answering some of your questions. Like you, I am no cosmologist (although I own a copy of Misner, Thorne, and Wheeler and have dug into it several times–but I lay no claim to understanding it thoroughly). I am an aerospace engineer with a fairly good grasp of mathematics and coordinate transformations.

  1. If a fixed earth coordinate transformation is made, there is no need to invoke general relativity. In the fixed-earth coordinate system there will be terms that allow for a geosynchronous satellite to follow a figure-eight orbit over a small region of the earth around its equator. Most physicists call them centripetal acceleration terms; followers of the geostationary theory will ascribe these terms to “the rotating distant cosmic masses.”

  2. The fact that one can use Newtonian mechanics does not in and of itself disprove Geocentricism. I stated in another thread that Geocentricism is simply a coordinate transformation and not a separate theory in and of itself. This coordinate transformation will introduce all sorts of wild and weird acceleration terms (I called them “fictitious forces,” I think) and as such is not as useful as the Copernican theory (modified to allow for the sun’s revolution about the galactic center and so on), whose equations are simpler. So Geocentricism is not wrong per se, it’s just not very useful. “The world really does revolve around engineers, because they get to pick the coordinate system.”

  3. I’m not sure what you mean by “analogous forces.” Please explain.

  4. I think this question is moot, since Geocentricism (at least the coordinate transformation version of it) is not disprovable. Even if it were, I don’t know enough about the relation between Geocentricism and general relativity to answer this question.

Now, if you would, please step over to the Non-Rigid Earth thread and answer my questions.

  • Liberian
    [/quote]

Thanks for the straight-forward answers, Liberian.

  1. What do you mean by “followers of the geostationary theory will ascribe these terms” to “the rotating distant cosmic masses.” Are you referring to me, or physicists in “real” aerospace situations who practice geostastionary theory.

  2. If the true underlying reality is Geocentrism, than it is more than a coordinate transformation.

  3. By analogous forces, I mean, that the rotating cosmic masses will produce forces on the geostationary earth which have an effect analogous to the centrifigal forces and Corliolis forces we feel on a rotating earth. I.e, weather patterns etc. will appear on the fixed earth as they do on a fixed position on a rotating earth. The forces may end up being formualted differently, but all the force interactions calculated due to a rtotating earth in a Newtonian system will occur in the general relativity case for the fixed earth.

Did you catch this in the original thread?

Hans Thirring created a geocentric model and proved that the forces we experience at earth and attribute to earth rotation / translation (i.e., inertial forces- Coriolis, centrifigal, etc.) are attributed to the rotating cosmic masses in the fixed earth case.

Hans Thirring concludes his paper with:

“…[font=TimesNewRoman][size=2]By means of a concrete example it has been shown that in an Einsteinian gravitational field, caused by distant rotating masses, forces appear which are analogous to the centrifugal and Coriolis forces.”[/size][/font]

Interestingly, in the Newtonian case, these are “fictitous forces”. In the Geocentric case, they are real forces.

  1. All you really need to know is Einstein’s equivalency principle, which says that the physics of the universe are the same in any chosen frame. If geostationary satellites sit over a point on the equator when doing the calculation from a rotating earth reference frame, it must sit over the same point in a fixed earth reference frame.

I have stepped.
[font=TimesNewRoman][size=2][/size][/font]

[quote=trth_skr]Thanks for the straight-forward answers, Liberian.

  1. What do you mean by “followers of the geostationary theory will ascribe these terms” to “the rotating distant cosmic masses.” Are you referring to me, or physicists in “real” aerospace situations who practice geostastionary theory.
    [/quote]

I called the Coriolis and centripetal “forces” fictitious; you said (I think) they were caused by rotating distant cosmic masses. That is what I meant. Probably any engineer trying to solve practical problems will use the terms without worrying too much about their origin.

  1. If the true underlying reality is Geocentrism, than it is more than a coordinate transformation.

What, precisely, do you mean by “true underlying reality”? You subscribe to Einstein’s equivalence principle and theories of relativity. The laws of physics do not allow us to distinguish between one reference frame and another.

  1. By analogous forces, I mean, that the rotating cosmic masses will produce forces on the geostationary earth which have an effect analogous to the centrifigal forces and Corliolis forces we feel on a rotating earth. I.e, weather patterns etc. will appear on the fixed earth as they do on a fixed position on a rotating earth. The forces may end up being formualted differently, but all the force interactions calculated due to a rtotating earth in a Newtonian system will occur in the general relativity case for the fixed earth.

Did you catch this in the original thread?

Hans Thirring created a geocentric model and proved that the forces we experience at earth and attribute to earth rotation / translation (i.e., inertial forces- Coriolis, centrifigal, etc.) are attributed to the rotating cosmic masses in the fixed earth case.

Hans Thirring concludes his paper with:

“…[font=TimesNewRoman][size=2]By means of a concrete example it has been shown that in an Einsteinian gravitational field, caused by distant rotating masses, forces appear which are analogous to the centrifugal and Coriolis forces.”[/size][/font]

Interestingly, in the Newtonian case, these are “fictitous forces”. In the Geocentric case, they are real forces.

Okay, but does Hans Thirring say how the distant rotating masses cause the forces?

I also note that his paper dates from 1918. What was a valid scientific debate ninety years ago (regarding whether the universe as a whole rotates, in this case) may have been settled since then. I point to the constancy of the speed of light as an example of this; in the 1930’s there was considerable debate over whether the speed of light decreased with time, oscillated, or was constant. Measurements since World War II settled the question pretty thoroughly.

  1. All you really need to know is Einstein’s equivalency principle, which says that the physics of the universe are the same in any chosen frame. If geostationary satellites sit over a point on the equator when doing the calculation from a rotating earth reference frame, it must sit over the same point in a fixed earth reference frame.

Ah, I see.

I have stepped.

Thank you. So have I.

  • Liberian

If the universe is rotating while maintaining the earth stationary at the center, then this is the reality of the universe.

Newtonian theory does not explain “how” two masses attract each other. Nor does general relativity. It is just accepted.

Thirring solved the equations for Einstein’s general relativity for the forces occuring in a rotating shell and demonstrated that the rotation of distant masses does create a gravitational fied that equals the centrifgal field.

Rosser (from the initial link) gives a more descriptive picture:

“Relative to the stationary roundabout [the Earth], the distant stars would have a velocity rw [radius x angular velocity] and for sufficiently large values of r, the stars would be moving relative to O’ [the observer] with linear velocities exceeding 3 x 10^8 m/sec, the terrestrial value of the velocity of light. At first sight this appears to be a contradiction…that the velocities of all material bodies must be less than c [the speed of light]. However, the restriction u < c = 3 x 10^8 m/sec is restricted to the theory of Special Relativity. According to the General theory, it is possible to choose local reference frames in which, over a limited volume of space, there is no gravitational field, and relative to such a reference frame the velocity of light is equal to c. However, this is not true when gravitational fields are present. In addition to the lengths of rods and the rates of clocks the velocity of light is affected by a gravitational field. If gravitational fields are present the velocities of either material bodies or of light can assume any numerical value depending on the strength of the gravitational field. If one considers the rotating roundabout as being at rest, the centrifugal gravitational field assumes enormous values at large distances, and it is consistent with the theory of General Relativity for the velocities of distant bodies to exceed 3 x 10^8 m/sec under these conditions.” (An Introduction to the Theory of Relativity, W. G. V. Rosser, London, Butterworths, 1964, p. 460)

Thirring was not proposing that the universe rotates. He was testing the results of the theory of general relativity for the presence of the strong principle. Still the solution demonstrates and validates that if one were to transform a coordinate system to a fixed earth, then solve the einsteinian equations, analogous forces to the centrifigal and Corliolis would apprear at the center of the rotating universe.

Since Thirring many more sophisticated models of rotating universes have been created. Thirring is the classic solution.

He did no such thing. Have you actually read his paper, or any part of it other than the concluding paragraph that Robert quotes and you reproduce? If you have read (and understood) it, I must say that I am surprised by how misleading your statement above is. There are two errors of fact in your claim:
a) Thirring did not create a geocentric model and
b) He did not prove that the Coriolis and centrifugal forces are attributed to the rotating cosmic masses in the fixed earth case

What he actually did was to model the field inside a uniformly
rotating infinitesimally thin hollow sphere of uniform surface density, and then model the motion of a point test mass within the sphere.

His result shows that forces appear *like *the centrifugal and Coriolis forces we experience as a result of the earth’s rotation. However, in his model, the centrifugal force, in addition to its normal radial component, has an axial component. To quote Thirring himself in explaining this unphysical result (Thirring, The effect of Rotating Distant Masses in Einstein’s Theory of Gravitation, Physicalishe Zeitschrift 19, 33 – 39):

‘The fact that in nature we only have been able to observe a radial, but never an axial component of the centrifugal force can be brought into agreement with the results here by noting that the approximation of the heaven of fixed stars by means of an infinitesimally thin hollow sphere is certainly not physical…As Einstein has shown in his cosmological work, these boundary conditions [used by Thirring in deriving the fields] are approximately fulfilled for a co-ordinate system in which the fixed stars average at rest. Our solution therefore does not represent the field of a hollow sphere “isolated in the cosmos” but the field inside such a hollow sphere outside which, at yet greater distances, masses are present that are, on average, at rest relative to the chosen co-ordinate system’

In other words, he modelled the effect of a rotating shell against the background of the star field and the rotation of the shell was with respect to the stars.

He then went on to model the effect on a particle on a rotating massless body at the centre of a rotating sphere (rotating again with respect to the stars) and derived expressions for, as he says it: ‘the centrifugal and Coriolis forces composed of the effects of their own rotation and those of the rotating hollow sphere’ where he is referring to rotation with respect to the stars. He concludes: ‘…we should not forget that in the problem discussed here we are not dealing with two bodies (the point mass and the sphere), but the fact is that as a result of the boundary conditions γμυ = 0 the more distant masses have to be taken into account as a third factor in determining the field; those masses being at rest with respect to our initially chosen co-ordinate system.’

In other words in order to derive the expressions for the field inside the rotating shell, he had to set boundary conditions which in effect mean that the shell is rotating with respect to the stars which are taken to be at rest.

So now you know what it was that Thirring modelled and what he showed, and it’s far from what you claimed.

  1. All you really need to know is Einstein’s equivalency principle, which says that the physics of the universe are the same in any chosen frame. If geostationary satellites sit over a point on the equator when doing the calculation from a rotating earth reference frame, it must sit over the same point in a fixed earth reference frame.

Einstein’s equivalence principle says no such thing. What it says is that the result of a *non-gravitational *experiment conducted in a local inertial reference frame is invariant with respect to the velocity of the frame or its position in spacetime. But it only holds for non-gravitational experiments and in local inertial (ie free-falling) frames. If you call on propositions such as EEP, it would be a good idea to know what they actually say, don’t you think?

Alec
evolutionpages.com

[quote=trth_skr] Will you do me the favor of offering your opinion on these questions:

  1. If a fixed earth coordinate transformation is made, and a solution for the force field at and near the earth were calculated using Einstein’s general relativity, would or would not the rotating distant cosmic masses produce forces at and near the earth analogous to those which describe the orbit of geosynchronous orbits of satellites using Newtonian mechanics and a rotating earth. Please consider Einstein’s equivalency principle.

  2. Would the fact that one can describe geosynchronous orbits of satellites using Newtonian mechanics in and of itself disprove Geocentrism?

  3. Would the fact that one can describe geosynchronous orbits of satellites using Newtonian mechanics automatically mean that analogous forces would not exist in the fixed earth case?

  4. If one were to claim that the fact that one could calculate the orbits of geosynchromous satellites using Newtonian mechanics led to the disproof of Geocentrism, would one not need to state that it also disproved Einstein’s genral relativity, or at least the (strong) equivalence principle?
    [/quote]

Simple answers:

[list]
*]The distant masses in this co-ordinate transformation would produce analogous forces in the Friedmann-Robertson-Walker solution to the Einstein field equations – whether or not they produce identical forces depends on the chosen boundary conditions of the universe
*]No, the fact that one can describe geosynchronous orbits of satellites using Newtonian mechanics does not in and of itself disprove geocentrism, but in a universe model with absolute space, Newtonian considerations such as geosynchronous satellites, Foucault’s pendulum and many other observations would disprove geocentrism
*]In the Newtonian model of absolute space analogous forces do not exist in the fixed earth case
*]Newtonian mechanics depends on an absolute space; there is no absolute space in the FRW metric of GR, so in that metric talk of a centre of the universe, and the notion of geocentrism or anycentrism is meaningless.
[/list]Your questions get to the fundamental inconsistency that lies at the heart of Robert’s position. Robert wants to show that the earth is the centre of the universe. The ‘centre of the universe’ only has meaning in a universe model with an absolute space (I assume that is why you are both desperate for an aether to exist). The best description we have of a universe with an absolute space is the Newtonian model (plus special relativity). In a Newtonian (absolute space) universe, for many utterly compelling reasons, the earth cannot be the unmoving centre of the universe. These reasons have been rehearsed many times and I don’t plan to repeat them here.

So, Robert then calls on GR, Einstein’s equivalence principle and Mach’s principle to demonstrate that the Newtonian reasons that disqualify the earth from being the centre of the universe don’t apply and that he can then call on other biblical ideas (and other deeply flawed physical ideas such as the claim that the rotating universe ‘stabilises the earth at its centre’ in which he utterly confounds solid body dynamics with many-body kinematics) to demonstrate geocentrism. The fact is that Robert repudiates GR, and so his position is logically untenable. Furthermore, even if he entirely accepted GR, he’d be no better off, because in GR, according to Einstein’s equivalence principle (and this holds also for the very strong equivalence principle that is even stronger than the EEP), and according to Mach’s principle, there is no absolute space and so it is meaningless to talk of a centre of the universe. GR is fundamentally acentric.

to be continued

Continuation

Let’s have some definitions:
Mach’s principle states that inertia is not absolute but depends on matter in the universe. Matter/energy there determines inertia here. There is no such thing as absolute rotation in the universe independent of the distribution of matter, and no absolute space. The closest we can get to a definition of absolute rotation is rotation with respect to the average distribution of matter in the universe: the distant stars; or rotation with respect to a local inertial frame (which is very closely aligned to the star field, although this alignment can be slightly perturbed by the influence of large nearby masses). See below.

The Einstein equivalence principle states that in a local inertial reference frame the outcome of any non-gravitational experiment is independent of the velocity of the frame or its position in spacetime and that the laws of nature are those of special relativity. This does NOT mean that rotation is the same as being static nor does it deny the special status of inertial reference frames; in fact, EEP holds ONLY in inertial reference frames.

GR states that the effect of a force resisting gravity and the effect of a force accelerating a reference frame are identical and indistinguishable. In GR, spacetime geometry is determined by the distribution of matter/energy in the universe (there is no absolute space) and the spacetime geometry influences the flow of matter/energy.

Are there any special reference frames in GR? Well, let’s do a thought experiment. Let’s imagine we are in a spacecraft, with blacked out windows, that is rotating so that the centrifugal force creates an artificial gravity – we are pinned against the walls of the craft by this force. We then employ the steering motors of the spacecraft to manoeuvre the craft so that all forces that we can measure within the craft disappear. We open the window blinds and what do we see? The craft is not rotating with respect the stars. The craft is now at rest within what we call a local inertial frame of reference, one in which there are no measurable residual forces due to linear acceleration or angular momentum. According to Mach, matter/energy there determines inertia here, so the inertial frame aligns with the star field. The local inertial frame is the only special frame in GR (the axis of rotation of gyroscopes remain at rest within an inertial frame – that’s how gyroscopic or inertial navigational systems work.)

Now we have seen that talking about a centre of the universe in GR (or at least as far as the Friedmann- Roberston-Walker metric solution to the Einstein field equations goes) is meaningless, but is it meaningless to talk about absolute rotation? Well when astronomers and cosmologists talk about rotation in the universe they do so with respect to local inertial frames (which we have seen are very closely aligned to the distant stars), or with respect to the star field itself. So in GR, the formal conclusion is that it is meaningless to posit absolute rotation independent of matter in the universe, but that inertial frames are special (in that they uniquely represent conditions with no detectable residual forces), they align with the star field according to Mach’s principle, and if absolute rotation means anything at all, it means being in a non-inertial reference frame where forces are detectable. The Earth’s surface is just such a non-inertial frame: by this definition it rotates.

To be continued

Continuation

A further example of your inconsistency is reference to the ‘gyroscopic rotation of the universe stabilising the earth at its centre of mass’. Leaving aside the fact that this confuses solid body dynamics with many-body kinematics, if you really believed in the equivalence of the rotating and static star field co-ordinate systems you would acknowledge that the ‘stabilising forces’ would have to exist in both co-ordinate systems – but where in the reference frame at rest with respect to the distant stars are we to find forces that prevent the earth from wandering off through the universe due to the influence of locally acting forces such as gravitational attraction to large masses. Indeed the measurement of the CMB anisotropy indicates a relative motion between the solar system and the primordial radiation of the early universe of 365 km/sec: in other words the earth is moving with respect to the spacetime manifold of the primordial universe as described by the Friedmann-Robertson-Walker metric at a speed of 365 km/sec. (Incidentally, the CMB also aligns with, ie does not rotate with respect to the star field and local inertial frames, so we can say that the star field frame and the local compass of inertia is at rest with respect to the spacetime manifold of the primordial universe as described by the FRW metric)

To summarise, in order for the ‘centre of the universe’ to have meaning, we need an absolute space. In such a space, Newtonian mechanics (plus special relativity) applies, and there are many compelling reasons in that system which show that the earth cannot be the unmoving centre. In order to refute these reasons, Robert calls on GR, but in GR talk of a centre is meaningless (Robert also vehemently denies GR so he really shouldn’t use it, but that’s another matter). In an absolute space model the earth cannot be at the centre and in a GR model there is no centre. Robert is caught in a fundamental logical inconsistency. He uses Einstein and Mach like a drunk uses a lamppost – for support rather than for illumination.

There is only so much time that can sensibly be devoted to correcting erroneous and ill-conceived notions and I have now exceeded that time.

Alec
evolutionpages.com

[quote=hecd2]He did no such thing. Have you actually read his paper, or any part of it other than the concluding paragraph that Robert quotes and you reproduce? If you have read (and understood) it, I must say that I am surprised by how misleading your statement above is. There are two errors of fact in your claim:
a) Thirring did not create a geocentric model and
b) He did not prove that the Coriolis and centrifugal forces are attributed to the rotating cosmic masses in the fixed earth case
[/quote]

Yes I have the paper.

I also said this:

Thirring was not proposing that the universe rotates. He was testing the results of the theory of general relativity for the presence of the strong principle. Still the solution demonstrates and validates that if one were to transform a coordinate system to a fixed earth, then solve the einsteinian equations, analogous forces to the centrifigal and Corliolis would apprear at the center of the rotating universe.”

I noticed that you did not mention the Rosser quote.This is more direct.

The interpretation of the Thirring results is correct, as evidenced by an authority even greater than you, Max Born.

Max Born. physicist and personal friend of Albert Einstein. He said in his famous book,“Einstein’s Theory of Relativity”,Dover Publications,1962, pgs 344 & 345:

"…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."

I did catch the bit about absolute space, and if you read the link I started this with, I do say:

“What is needed ultimately is to get back to an aether based theory of the universe and try to explain physical mechnisms for things like grtavity. Many in quantam mechanics are reintroducing aether (under different names- space foam, quintessence, etc.).”

If you read the paper, he specifically discusses the Corliolis force.

[quote=hecd2]What he actually did was to model the field inside a uniformly rotating infinitesimally thin hollow sphere of uniform surface density, and then model the motion of a point test mass within the sphere.

His result shows that forces appear *like *the centrifugal and Coriolis forces …
‘The fact that in nature we only have been able to observe a radial, …"
[/quote]

I agree that the Thirring model is limited. But Born’s interpretation supports what I am saying, and I went on to say:

“Since Thirring many more sophisticated models of rotating universes have been created. Thirring is the classic solution.”

Thus the Rosser quote, which you totally ignored.

I will look further into EEP.

Thank you for the straight forward answers. I don’t mind the criticism, either. I learn a lot from it.

I do think you are a little over zealous in trying to defend your position. This is a Catholic discussion forum, not a peer reviewed journal.

[quote=hecd2]Simple answers:
The distant masses in this co-ordinate transformation would produce analogous forces in the Friedmann-Robertson-Walker solution to the Einstein field equations – whether or not they produce identical forces depends on the chosen boundary conditions of the universe
[/quote]

[quote=hecd2]No, the fact that one can describe geosynchronous orbits of satellites using Newtonian mechanics does not in and of itself disprove geocentrism, but in a universe model with absolute space, Newtonian considerations such as geosynchronous satellites, Foucault’s pendulum and many other observations would disprove geocentrism
[/quote]

Foucalt’s pendulum does not distinguish between a rotating earth and a rotating universe. Einstein himself (invoking Thirring) explained this:

[left]Einstein wrote to Ernst Mach on June 25, 1913:[/left]

“If one accelerates a heavy shell of matter S, then a mass enclosed by the shell experiences an accelerative force. If one rotates the shell relative to the fixed stars about an axis going through its center, a Coriolis force arises in the interior of the shell, that is, the plane of a Foucault pendulum is dragged around.”

[quote=hecd2]In the Newtonian model of absolute space analogous forces do not exist in the fixed earth case
[/quote]

What about the Thirring paper and the Born quote?

Does not the relativistic case for rotating / translating earth collapse to a Newtonian like (flat space) solution. Basically, Special relativity with much less than light speed velocities?

Alternately the fixed earth case invokes the strong principle an is very non-Newtoinian like.

I understand that GR has no absolute space, but cannot one can compare reference frames?

[quote=hecd2]Newtonian mechanics depends on an absolute space; there is no absolute space in the FRW metric of GR, so in that metric talk of a centre of the universe, and the notion of geocentrism or anycentrism is meaningless.
[/quote]

see above.

[quote=hecd2]…

So, Robert then calls on GR, Einstein’s equivalence principle and Mach’s principle to demonstrate that the Newtonian reasons that disqualify the earth from being the centre of the universe don’t apply …
[/quote]

I will not speak for Robert, but I was using GR to demonstrate that having a Newtonian solution for geosynchronous satellites does not mean that there is not a GR solution for geosynchronous satellites in the fixed earth case. Thus saying that the forces to describe geosynchronous satellites in the fixed earth case are possible.

I never stated that this proves Geocentricity (and I will say that neither has Robert). It certainly does add some support to the possibility of Geocentricity.

Oh really?!

Your logic would imply that Max Born is also a greater authority than you, too.

So tell us, what scientific authority DO YOU claim to have in which you guarantee to be interpreting the work of Max Born correctly over the interpretation of Alec?

His explanation over zealous or was your explanation inadequate?

Tell me, what physical properties does the earth possess that would cause the entire universe to rotate around it rather than another planet with like qualities?

[quote=SocaliCatholic]His explanation over zealous or was your explanation inadequate?
[/quote]

The over zealousness is not related to the science, but rather the attitude.

[quote=SocaliCatholic]Tell me, what physical properties does the earth possess that would cause the entire universe to rotate around it rather than another planet with like qualities?
[/quote]

The fact that God placed the earth in the center of the universe, and not the other planets.

Geocentricism? In the 21st century? :eek:

I go away for a few days and see what happens……the board goes wacky

[quote=Liberian]* What, precisely, do you mean by “true underlying reality”? You subscribe to Einstein’s equivalence principle and theories of relativity. The laws of physics do not allow us to distinguish between one reference frame and another.*
[/quote]

[quote=trth_skr] If the universe is rotating while maintaining the earth stationary at the center, then this is the reality of the universe.
[/quote]

trth_skr,

Now we are getting into a question of the philosophy of science. Given two theories that both predict exactly the same results, which theory do you believe? Generally scientists will tend to believe the simpler theory.

As an example, back in the mid-twentieth century a theory was proposed that emeralds are a color called “grue,” which was green until midnight of January 1, 2000, GMT, at which point it changes to blue. Any observation of the color of an emerald before January 1, 2000 would confirm both the theory that emeralds are green and the theory that emeralds are grue. So why didn’t anybody take the theory of “grue emeralds” seriously? Because it was more complicated.

In the same way, we have the theory that the universe as a whole is non-rotating and the earth rotates as part of it, and we have the theory that the earth does not rotate and the universe rotates around it. The only difference between the two theories is a coordinate transformation. The equations of motion from the geocentric theory include a bunch of acceleration terms that the equations of motion from the other theory do not. Which theory is preferable as a scientific theory? I maintain that it is the other theory.

Science does not deal in “underlying reality.” Science deals with observations. If you are going to talk about the “underlying reality,” you are leaving the realm of science and getting into philosophy.

  • Liberian

[quote=Liberian]Now we are getting into a question of the philosophy of science. Given two theories that both predict exactly the same results, which theory do you believe? Generally scientists will tend to believe the simpler theory.
[/quote]

generally, perhaps. but not so generally that “simplicity” is a singularly helpful signpost or even a rough synonym for “truth”.

parsimony is only one of many properties that are used by theoreticians to differentiate between theories; the very idea of “simplicity” itself isn’t as straightforward as you seem to be suggesting. for example, simplicity to william of ockham was initially stated as a proscription against multiplying the number of entities in an explanation; simplicity in the mathematical formalism of a theory means something else entirely. and so on.

[quote=Liberian]As an example, back in the mid-twentieth century a theory was proposed that emeralds are a color called “grue,” which was green until midnight of January 1, 2000, GMT, at which point it changes to blue. Any observation of the color of an emerald before January 1, 2000 would confirm both the theory that emeralds are green and the theory that emeralds are grue. So why didn’t anybody take the theory of “grue emeralds” seriously? Because it was more complicated.
[/quote]

this is the “new riddle of induction” proposed by a philosopher named Nelson Goodman in his book Fact, Fiction, and Forecast; it is not a “theory” so much as the statement of an age-old problem that has its focal point in the tension between deductive and inductive reasoning. theoretical simplicity doesn’t really enter the picture.

[quote=Liberian]Science does not deal in “underlying reality.” Science deals with observations. If you are going to talk about the “underlying reality,” you are leaving the realm of science and getting into philosophy.
[/quote]

this is itself a philosophical statement, and an enormously controversial one - it is known as (positivistic) “instrumentalism”, the theoy that all that matters about scientific theorizing is that it accurately predict experimental results. by that measure, of course, ptolemy’s epiyclical theory is just as, if not more, “true” than copernican or keplerian mechanics.

by far what most scientists believe themselves to be doing, however, when they create models, is painting a picture of how the actually is, in and of itself, quite apart from our observations or descriptions of it.

ironically, you yourself seem to reject instrumentalism when you apply the criterion of parsimony; preferring the simpler theory is typically understood as a way of preferring the theory that is more likely to be ***true. ***

which means that only one of the two propositions “the universe revolves around a stationary earth” and “the earth revolves around a star that is itself revolving around a mobile galactic center” can be true.

basically, it’s impossible to avoid doing philosophy when doing science, since anything you do beyond reading numbers off of a measuring device, or describing tracks in a cloud-chamber, or taking radio-wave photographs of quasars, is to say what those measurements and words and pictures mean; it is to interpret them. and that’s doing philosophy.

trth_skr,

Now we are getting into a question of the philosophy of science. Given two theories that both predict exactly the same results, which theory do you believe? Generally scientists will tend to believe the simpler theory.

As an example, back in the mid-twentieth century a theory was proposed that emeralds are a color called “grue,” which was green until midnight of January 1, 2000, GMT, at which point it changes to blue. Any observation of the color of an emerald before January 1, 2000 would confirm both the theory that emeralds are green and the theory that emeralds are grue. So why didn’t anybody take the theory of “grue emeralds” seriously? Because it was more complicated.

In the same way, we have the theory that the universe as a whole is non-rotating and the earth rotates as part of it, and we have the theory that the earth does not rotate and the universe rotates around it. The only difference between the two theories is a coordinate transformation. The equations of motion from the geocentric theory include a bunch of acceleration terms that the equations of motion from the other theory do not. Which theory is preferable as a scientific theory? I maintain that it is the other theory.

Science does not deal in “underlying reality.” Science deals with observations. If you are going to talk about the “underlying reality,” you are leaving the realm of science and getting into philosophy.

  • Liberian

Liberian:

One of the main points IS that science is largely philosophy. What happens when you takle into account that God CHOSE to place the earth at the center of his creatoin? Of course sceintific dogma does not allow one to consider God as having an effect in his creation.

Look again at this quote from George Ellis:

“People need to be aware that there is a range of models that could explain the observations,…For instance, I can construct you a spherically symmetrical universe with Earth at its center, and you cannot disprove it based on observations.” Ellis has published a paper on this. “You can only exclude it on philosophical grounds. In my view there is absolutely nothing wrong in that. What I want to bring into the open is the fact that we are using philosophical criteria in choosing our models. A lot of cosmology tries to hide that.”.

W. Wayt Gibbs, “Profile: George F. R. Ellis,” Scientific American, October 1995, Vol. 273, No.4, p. 55.

www.veritas-catholic.blogspot.com

[quote=john doran]generally, perhaps. but not so generally that “simplicity” is a singularly helpful signpost or even a rough synonym for “truth”.


basically, it’s impossible to avoid doing philosophy when doing science, since anything you do beyond reading numbers off of a measuring device, or describing tracks in a cloud-chamber, or taking radio-wave photographs of quasars, is to say what those measurements and words and pictures mean; it is to interpret them. and that’s doing philosophy.
[/quote]

Excellent exposiotion on the philosophy of science.

I have not read the book, but there is a book dealing with the simplicity issue called:

Mario Bunge, The Myth of Simplicity, (Englewood Cliffs, New Jersey: Prentice Hall, 1963)

www.veritas-catholic.blogspot.com

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