Admitting the falsity in Relativity FE/Ferrari effect

I have been holding to this idea that the Earth is flat under a curved space-time manifold as defined by General Relativity. Basically, a satellite travels a straight geodesic through space-time and traverses the Earth in a straight line, and the Earth's surface is like a geodesic in this manifold, able to be classified as some flat hypersurface in space-time. This effect of curved space-time giving a flat earth that appears curved is the Ferrari Effect. So, in sum, it was that general relativity seemed to demonstrate Earth is flat.
Well, as open-minded as I try to be, I admit I am wrong about the Ferrari effect and the adequacy of this model. Here is my summary of what changed my mind on it:

So basically, a flat surface by definition has a curvature of 0 obviously, and there is a measure known as 'Gaussian curvature' which is simply a product of referencing a surface to a tangent plane (which is a 2D flat plane), and a surface with a positive curvature (curving like a sphere) will give the non-euclidean characteristics of converging parallel lines as geodesics and the 270 degree triangle. If we have test objects moving through space-time in their straightest path possible, they will converge and can triangulate to three paths being perpendicular to the other. This demonstrates that in curved space-time, Earth does indeed have positive curvature and thus cannot be flat (since a flat surface has a Gaussian curvature of 0).
We got the earth in the 4D space-time manifold, and it has curved space-time as a field around it. We have vector P and M, they represent the momentum geodesics of mass's, with both of them having the equivalent momentum. In an extrinsically curved surface with a Gaussian curvature of 0, we may have what appears to be a curved manifold, but it has no intrinsic curvature because the vectors or lines in such a 3D Cartesian coordinate system remain equivalent to how they would be in a 2D Euclidean plane, where the principal curvature doesn't deviate from a reference tangent plane. Now, a positive Gaussian curvature gives some unique properties, which are impossible under a flat euclidean space and plane, we know that positive curvature can converge parallel lines (as geodesics) and give a circle with a circumference of < 2* pi* r on the surface, as well as a triangle >180 degrees. That is why a spherical surface is considered non-euclidean. Now, we have a sphere with a Gaussian curvature of 1/r^2 consistently across it, with r as the radius of the sphere (knowing Gaussian curvature is the product of principle curvatures k1 and k2 such that K=k1k2). So, now we place a tangent plane on the Earth in curved space-time, and we realize that the surface matches a positive Gaussian curvature of a sphere, since the momentum vectors of the mass's meet despite being geodesics in curved space-time. By comparing this to the positive Gaussian curvature of a sphere or a 3D non-euclidean sphere in a Cartesian coordinate system, we realize the principle curvatures dictate a change in the z axis coordinate, giving the unique properties of positive curvature. So, even assuming general relativity, it debunks itself by showing the Ferrari effect is not a valid determination of a flat earth.

At this point, I am now under the persuasion that Earth is round (spheroid) under General Relativity and can't be flat. So, I don't hold to this principle anymore.

Another way of refuting such a concept is to dismantle General Relativity like Sandokhan tries to do, but as you can see, you don't need to, the Ferrari effect simply isn't adequate and so even under GR, this concept debunks itself. I just needed to learn more of these concepts and expand my understanding.

Some illustrations:

Surface with 0 Gaussian curvature but extrinsic curvature by a change in coordinates in 3D space (but a consistent 2D plane):


Intrinsic curvature, with lines as paths of momentum geodesics (I use momentum because it is representing the mass at particular velocity, which of course changes in curved space-time), they converge:


Now, you'll realize that only with positive Gaussian curvature is this possible, which is the sphere in this picture, and the middle cylinder has none.


Now, if you have one satellite at the equator, tracing geodesic lines, one following the prime meridian and another at a latitude line crossing 90 E, and they will trace out paths perpendicular to each other. This indicates not only positive Gaussian curvature, but also at 1/r^2 as indicated by Spherical geometry.

This means that given General Relativity, Earth is indeed curved and not flat.

I have been holding to this idea that the Earth is flat under a curved space-time manifold as defined by General Relativity. Basically, a satellite travels a straight geodesic through space-time and traverses the Earth in a straight line, and the Earth's surface is like a geodesic in this manifold, able to be classified as some flat hypersurface in space-time. This effect of curved space-time giving a flat earth that appears curved is the Ferrari Effect. So, in sum, it was that general relativity seemed to demonstrate Earth is flat.
Well, as open-minded as I try to be, I admit I am wrong about the Ferrari effect and the adequacy of this model. Here is my summary of what changed my mind on it:

I haven't followed the logic of what you are saying, (it's a bit above "my pay grade") but in my view GR has nothing to say about the shape of the earth or any other object.
One way of describing GR is that it extends the Newtonian laws of motion and gravitation to velocities significant compared to c and the mass "not too large". JackBlack can describe it much better than I.

GR does not significantly change the shape of any object with the masses of any solar system object.

Under GR, the space around earth is very slightly non-Euclidean, but by an immeasurably small amount.
In the non-Euclidean space caused by a spherical mass, a circle's circumference is not precisely 2 x π x r.
The nett effect is that under GR the earth's diameter is about 4 mm larger than it would otherwise be to contain the same volume.
Similarly under GR the sun's diameter is about 1 m larger than it would otherwise be.

These effects  are so small as to be unmeasurable except for some extremely precise astronomical measurements.

Yes, under GR, a satellite or any other object in "free fall" is travelling along a geodesic in spacetime, but the space component is so near Euclidean that satellites, projectiles and anything else in "free fall" simply traverse the paths we all accept under the Newtonian laws.

The very slight deviations have the effect of making the orbits if satellites precess very slightly, but no artificial satellite has been in orbit long enough for this to be observable.

My whole point is to stress that GR itself does not make the earth a Globe, other than the resultant gravitation always causing bodies as large as the earth to collapse to be almost spherical. The only significant deviation from a sphere is caused by rotation.

One little "addendum".
Here is a good introduction the effect of GR on the geometry of space near say the earth or the sun:

I haven't followed the logic of what you are saying, (it's a bit above "my pay grade") but in my view GR has nothing to say about the shape of the earth or any other object.

Actually, as of now, I see General Relativity as demonstrating the Earth is round (spheroid), this is because the surface of the Earth as triangulated by satellites orbiting trace paths showing a positive Gaussian curvature. Curved space-time has the path of a particular momentum and spatially, geodesics on the Earth's surface indicates a positive Gaussian curvature.

I used to think it showed a flat earth but I realized how flat and curved geometry is properly defined and GR is a spherical earth concept.

One way of describing GR is that it extends the Newtonian laws of motion and gravitation to velocities significant compared to c and the mass "not too large". JackBlack can describe it much better than I.

JackBlack had some noteworthy points on it, it wasn't anything to do with this criticism here exactly, it was a different approach, but the fact that the straightest possible path varies by the initial momentum of an object with space-time shows how using satellites like Davis does to show Earth must be flat with the Ferrari effect is simply incorrect.

GR does not significantly change the shape of any object with the masses of any solar system object.

GR and Newtonian Gravity actually give the Earth curvature in how they are described, the point center of mass is the basis of gravitational attraction, making a sphere the only efficient and stable geometry given Newton's Gravity or GR. If someone asked you, "Why is the Earth a spheroid?" I am quite sure you (or at least most others) would say 'Gravity', and as is known and you have pointed out before, GR and Newtonian Gravitation are quite similar.

Under GR, the space around earth is very slightly non-Euclidean, but by an immeasurably small amount.

Well, curved space-time is why the Earth is spatially round in General Relativity

Yes, under GR, a satellite or any other object in "free fall" is travelling along a geodesic in spacetime, but the space component is so near Euclidean that satellites, projectiles and anything else in "free fall" simply traverse the paths we all accept under the Newtonian laws.

Yes, but it does this due to the non-homogenous space-time region.

The very slight deviations have the effect of making the orbits if satellites precess very slightly, but no artificial satellite has been in orbit long enough for this to be observable.

Orbits in GR would indicate a Gaussian curvature of approximately 1/r^2, making it approximately a sphere (yes, 'oblate' if you wish due to rotation and the orbiting moon).

My whole point is to stress that GR itself does not make the earth a Globe, other than the resultant gravitation always causing bodies as large as the earth to collapse to be almost spherical. The only significant deviation from a sphere is caused by rotation.

GR is a theory of gravity, explaining it in a different way than Newtonian Gravitation, but it results in a Globe regardless, Non-euclidean.

But yeah, it seems I was wrong about Earth being flat in GR, it would actually be round.

GR is a theory of gravity, explaining it in a different way than Newtonian Gravitation, but it results in a Globe regardless, Non-euclidean.

I guess I "sort of" agree with what you are saying, but the point I have been trying to make all along is that the Newtonian Laws of Motion and Gravitation explain it all almost perfectly.

Well before Einstein came along astronomers had measured the precession of the perihelion of planetry orbits.
They found for the inner three planets the values shown here (not including the "Prediction GTR"):See more in Epstein, Relativity, The Precession of the Perihelion of Mercury
I think that the almost can be justified when there are so many asteroids, etc, that cannot be accounted for.
Then, of course, Einstein came along with his GR and explained the slight observed discrepancies.

What leaves me in awe is the precision that those old astronomers could achieve, not only with the measurements of precision of a few arcseconds per century, but with the precision of their calculations based on Newtonian mechanics of the effects of the other planets, etc - all with hand calculations!

There is nothing wrong with Newtonian mechanics for everyday calculations or even orbital calculation - after all, it is what used for all except the most advanced particle physics of cosmological calculations.

All the manned space missions right from the early Mercury and Gemini through to the lunar landings used simply Newtonian mechanics. In the earlier these were calculated by a team of "human computers", see These women were the "computers" that did the orbital calculations for the early space missions.

The Black Female Mathematicians Who Sent Astronauts to Space
space program, starting with the Mercury missions in the ‘50s and early ‘60s, through the Apollo moon missions in the late ’60s and early ‘70s, and ending with the space shuttle missions in the mid '80s. Among other things, she calculated the trajectories of America's first manned mission into orbit and the first Moon landing.

From: The Black Female Mathematicians Who Sent Astronauts to Space

You cannot do even Schwarzschild metric approximations to GR that way - you need pretty advanced computers and do it numerically.

Relativistic corrections are then added where they are needed.

My big beef is when people drag in GR quite unnecessarily and in many cases to big-note themselves or to confuse their readers.
GR is totally unnecessary in any debate on the shape of the earth - old Newton gives the same answers in almost all cases to a better accuracy that we can hope to measure.
The exception to this is in "time dilation" due to velocity and/or gravitational potential and this is simply due to the extraordinary precision that can be achieved in time measurement.

But yeah, it seems I was wrong about Earth being flat in GR, it would actually be round.

No problem! Looks like you're in good company:

Anyone who has never made a mistake has never tried anything new.

But I would disagree a little with the way you put that.
GR itself cannot cause the earth to be flat or a Globe any more than Newtonian mechanics can.
It is Gravitation that is the cause of all astronomical bodies over a few hundred kilometres in diameter being more or less spherical.
And "Newton's Law of Universal Gravitation" or "General Relativity" are just theories explaining how gravitation behaves.
"General Relativity" is no more the final answer as to the cause of gravitation than was "Newton's Law of Universal Gravitation".

Sorry, this got long again!

PS Another interesting topic is the ellipticity of planets, and how it fits with there size and rotational period.
     A bit in Flat Earth Debate / Re: Gravity does not always make spheres

I guess I "sort of" agree with what you are saying, but the point I have been trying to make all along is that the Newtonian Laws of Motion and Gravitation explain it all almost perfectly.

Well before Einstein came along astronomers had measured the precession of the perihelion of planetry orbits.
They found for the inner three planets the values shown here (not including the "Prediction GTR"):

See more in Epstein, Relativity, The Precession of the Perihelion of Mercury
I think that the almost can be justified when there are so many asteroids, etc, that cannot be accounted for.
Then, of course, Einstein came along with his GR and explained the slight observed discrepancies.

What leaves me in awe is the precision that those old astronomers could achieve, not only with the measurements of precision of a few arcseconds per century, but with the precision of their calculations based on Newtonian mechanics of the effects of the other planets, etc - all with hand calculations!

(By the way, I have a query with the 579.16 arcsecs/century figure for Mercury - I must chase it up.)

There is nothing wrong with Newtonian mechanics for everyday calculations or even orbital calculation - after all, it is what used for all except the most advanced particle physics of cosmological calculations.

You cannot do even Schwarzschild metric approximations to GR that way - you need pretty advanced computers and do it numerically.

Relativistic corrections are then added where they are needed.

Yes, and my point here was that General Relativity derives a round earth, as well as Newtonian Mechanics. Those would explain why the Earth would be a spheroid.

GR is totally unnecessary in any debate on the shape of the earth - old Newton gives the same answers in almost all cases to a better accuracy that we can hope to measure.

It may not be necessary, but I previously thought that it derived a flat earth, and so used it as a justification. So that was how it became relevant for me.

But I would disagree a little with the way you put that.
GR itself cannot cause the earth to be flat or a Globe any more than Newtonian mechanics can.
It is Gravitation that is the cause of all astronomical bodies over a few hundred kilometres in diameter being more or less spherical.
And "Newton's Law of Universal Gravitation" or "General Relativity" are just theories explaining how gravitation behaves.
"General Relativity" is no more the final answer as to the cause of gravitation than was "Newton's Law of Universal Gravitation".

Don't see how this disagrees, both GR and Newtonian Gravity even in their differing descriptions of gravity derive a round earth (with a stable finite point mass). So, It is quite relevant to debating spheroid vs flat earth (otherwise, I don't know what you meant by that point).

Quote from: rabinoz on November 16, 2017, 05:22:31 PM

And "Newton's Law of Universal Gravitation" or "General Relativity" are just theories explaining how gravitation behaves.
"General Relativity" is no more the final answer as to the cause of gravitation than was "Newton's Law of Universal Gravitation".

Don't see how this disagrees, both GR and Newtonian Gravity even in their differing descriptions of gravity derive a round earth (with a stable finite point mass). So, It is quite relevant to debating spheroid vs flat earth (otherwise, I don't know what you meant by that point).

Yes, the bottom line is, apart from the "Infinite Plane Flat Earth", if Gravitation is real the earth cannot be flat.
And that is why most flat earthers fight tooth and nail to ridicule and "debunk" gravitation.

I don't think there's any real conflict. For all practical purposes Newton and Einstein say the same thing and that is of course not accidental. Einstein fully accepted that Newton Graviation was completely accurate in the "zero velocity" and "zero mass" limit, so GR has that designed into it.
And this "zero velocity" and "zero mass" limit covers any velocity and mass most of us will meet.

The only objection I have is the introduction of GR into the explanation when it is not needed, when GR is simply too complex to allow anything but numerical solutions in most cases.

The following may go against what I have been saying, but:
There is an "experiment" in Western Australia about teaching General Relativity to young children GR before exposing to Newton's Gravitation.
See, Australasian Science, Why don't we teach Einstein's theories in school? By David Blair
Apparently, it was very successful, though to be practical Newton's Laws of Motion and Gravitation would have to be presented as a practical approximation valid in almost all situations.

I see it as similar to teaching electromagnetic theory from a purely quantum and relativistic theoretic point of view, where:

• Electrostatic forces are mediated by the exchange of virtual photons.
• Magnetic fields and magnets do not exists as separate entities, but are a result of the relativistic motion of charges in a conductor.
• etc, etc.

Though, maybe if some of this was better understood, gravitation mediated by virtual gravitons and gravitation waves being a result of gravitons may not seem so strange.

In other words Newton's Laws of Motion and Gravitation are approximations that are quite accurate within their range of validity.
But this is no different from so many "physical laws".
The gas laws only apply over limited ranges of pressure and temperature and Ohm's law only fails at very low voltages or very high current densities.

Then what do you mean by this?

but in my view GR has nothing to say about the shape of the earth or any other object.

Then what do you mean by this?

Quote from: rabinoz on November 16, 2017, 03:17:55 AM

but in my view GR has nothing to say about the shape of the earth or any other object.

I could have worded it better. Certainly i agree that the earth is almost spherical because of gravitation,
but it does not matter whether that gravitation is caused by Newton's mass attracts mass GR's curved spacetime.

That GR itself has nothing more to do with the shape of the earth, other being the current theory of gravitation.

I'm not trying to disparage GR in any way, just to discourage the unnecessary use of it where it is not needed.

And GR solved a an object moving near the surface of a spherical object like the earth simply reduces to Newton's Laws plus the Coriolis effect.
See "Newton's Law if Gravitation" in schwarzschild solution in general relativity - GFM.

This is just getting more and more complicated.
As you may have determined, there are multiple things that flat can mean, just like there are multiple things straight can mean.

Having a positive gaussian curvature just means the surface isn't flat in Euclidean space.

The orbital paths has no impact on the shape of Earth.
What shows Earth to be round (at least in regards to the satellites), is the distance from the satellites to various points on Earth's surface, in a single instant, matches that of a curved surface, not a flat surface.

Well, as open-minded as I try to be, I admit I am wrong about the Ferrari effect and the adequacy of this model.

 I just needed to learn more of these concepts and expand my understanding.

Just a small diversion from the math for a moment to just point out how great it is that you were willing to express these two thoughts.  Every debate, on every topic, in every forum would be vastly improved by more people being willing to own an error and express that more understanding changed perception rather than just digging in and trying to avoid being wrong.  Errors are part of the human condition, and denying they exist in one's self is delusional. 

I applaud your honesty, and I hope others can follow your example.   

As you may have determined, there are multiple things that flat can mean, just like there are multiple things straight can mean.

Yes, you can define it in multiple ways. However, this one stands out because it is a basic and common definition in differential geometry, giving a flat plane and sphere differing characteristics as referenced to tangent planes in 3D Euclidean space, principal curvatures classified show the differences in positive, negative, and no curvature.

Having a positive gaussian curvature just means the surface isn't flat in Euclidean space.

Yes, and space is very nearly euclidean in the Earth's vicinity, and we can extend a plane that is equivalent to inertial satellites traversing a circular orbit being non-inertial in respect to an independent observing reference frame.

The orbital paths has no impact on the shape of Earth.
What shows Earth to be round (at least in regards to the satellites), is the distance from the satellites to various points on Earth's surface, in a single instant, matches that of a curved surface, not a flat surface.

Actually, it does, if you extend a tangent plane across space representing the x, y, and z axis, we see that the spherical curvature of 1/r^2 is present on the Earth, as the principal curvature from the tangent planes indicate, the ability of three satellite geodesic path's to cross perpendicular to each other can only be represented by positive curvature. Parallel lines cannot meet in a flat plane (if they were to be distorted by positive curvature distortion, they would have to be corrected by a negative curvature to keep them constantly parallel), but they do on the surface of Earth in GR, as well as momentum geodesics of test mass's in orbit. Also, as I believe you have pointed out or at least implied in the past, the path of orbiting objects only applies to specific smaller masses under a particular initial velocity that works with the curved space-time metric, with time being the major factor in that particular mass and velocity being able to orbit. So, in a coordinate plane (representing the spatial coordinates of Earth and around it), Earth is very well near Euclidean and can only match a sphere.

And yes, you are right, but it ends up going back to this, a non-euclidean space like the Earth has positive curvature, not matching a flat plane but rather a sphere. Non-euclidean flat surfaces do not exist, a flat plane meets Euclid's axioms, unlike Earth in GR.

Yes, you can define it in multiple ways. However, this one stands out because it is a basic and common definition in differential geometry, giving a flat plane and sphere differing characteristics as referenced to tangent planes in 3D Euclidean space, principal curvatures classified show the differences in positive, negative, and no curvature.

While admittedly I do not understand it entirely, how does it do this?

As far as I knew, Gaussian curvature is the product of the 2 principle curvatures. How are they determined?

When I look it up on wikipedia, it appeals to Euclidean geometry to determine the principle curvature.

This only seems to apply to 3D Euclidean space.

4D becomes more complex as you have 3 principle curvatures, and in non-Euclidean space you have the issue of defining the principle curvature.

So I seriously doubt the applicability of it with orbits.

Actually, it does, if you extend a tangent plane across space representing the x, y, and z axis, we see that the spherical curvature of 1/r^2 is present on the Earth

Which has nothing to do with the satellites.

An orbit in spacetime is in a 4D space.

Parallel lines cannot meet in a flat plane

Only for Euclidean space (depending on how you define a parallel line).

And yes, you are right, but it ends up going back to this, a non-euclidean space like the Earth has positive curvature, not matching a flat plane but rather a sphere. Non-euclidean flat surfaces do not exist, a flat plane meets Euclid's axioms, unlike Earth in GR.

Earth's surface can be represented in non-Euclidean space, but this has nothing to do with orbits or GR.

While admittedly I do not understand it entirely, how does it do this?

Basically, a normal vector for each point on a surface can be derived, with a normal plane crossing through it at that point (and since it is a unit normal vector, the vector or line is perpendicular to the normal plane). This is basically a tangent plane that touches at a particular point or a surface intersecting with a normal plane. The surface crossing through this plane will determine the curves, the curves are what touches the plane. At different points on the surface, there may be differing curves with the plane and normal vector, but the maximum value of curvature at a point and minimum value of curvature are k1 and k2 (which are the principle curvatures), in which the Gaussian curvature is K=k1k2. On a sphere, it is consistently 1/r^2 (r as the radius of the sphere), and a flat plane has zero. While a surface can be extrinsically curved (like a cylinder having 0 Intrinsic Gaussian curvature but still curves in a 3D manifold), intrinsic curvature is what an observer can determine on the surface by, for example, triangulating a 270 degree triangle. I guess this is one limitation of this definition since in a 3D space, a surface with 0 Gaussian curvature is not able to be traversed in a straight line like a flat plane with no extrinsic curvature by excluding this to a 3D Cartesian coordinate system.

But regardless, this shows Earth is curved and so not flat in accordance with GR, by a common differential geometry definition.

And yes, this is for exclusively 3D Euclidean space.

I am no expert or experienced person in differential geometry, but from what I got out of it and it seems to show that I was wrong about the Ferrari effect and GR showing earth to be flat (there were other problems as well but this was the turning point for me).

Here are some illustrative examples:

4D becomes more complex as you have 3 principle curvatures, and in non-Euclidean space you have the issue of defining the principle curvature.

There is able to be a 2D plane cross section in a non-euclidean space to determine principal and therefore Gaussian curvature, so Euclidean spaces can be derived to have a surface of a sphere in euclidean space to have a surface with the same Gaussian curvature in non-euclidean spaces. Also, like I said, the spaces around earth are very nearly euclidean in GR, it is precisely time itself as part of space-time that has the paths of a satellite following particular geodesics, but in a spatial coordinate system, Earth is spherical.

An orbit in spacetime is in a 4D space.

3D space, there is no 4D space in GR, so I don't know what you mean here exactly unless you are considering t to be a distinct plane of principle curvature.

Only for Euclidean space (depending on how you define a parallel line).

Which flat surfaces don't seem to be workable in. Even in a non-euclidean space, a sphere with nearly identical volume in a Euclidean coordinate system will both have the same positive Gaussian curvature as determined by characteristics of positive curvature in reference to the tangent planes, and such non-euclidean spaces can be referenced to Euclidean tangent planes like inertial orbits are technically non-inertial in respect to an independent observing frame. This is especially so in something like GR.

Earth's surface can be represented in non-Euclidean space, but this has nothing to do with orbits or GR.

Indeed, but my point was that in Non-euclidean spaces, a flat surface is not an option. This is from what I understand by looking into these definitions of flat and curved in geometry, I was pointed to this after asking about it and it seems it does in fact show Earth is round in GR.

And yes, this is for exclusively 3D Euclidean space.

i.e. is irrelevant for GR with non-Euclidean space-time.

I am no expert or experienced person in differential geometry, but from what I got out of it and it seems to show that I was wrong about the Ferrari effect and GR showing earth to be flat (there were other problems as well but this was the turning point for me).

They are completely different issues.

3D space, there is no 4D space in GR, so I don't know what you mean here exactly unless you are considering t to be a distinct plane of principle curvature.

Space time is an example of a 4D space. Time is one of the dimensions.

Which flat surfaces don't seem to be workable in. Even in a non-euclidean space, a sphere with nearly identical volume in a Euclidean coordinate system will both have the same positive Gaussian curvature as determined by characteristics of positive curvature in reference to the tangent planes

And this just goes back into the issue of making a tangent plane in non-Euclidean spaces.

The Ferrari Effect is fact. As much so as it follows directly from Newton's Laws. To dismiss that, is to dismiss the basis of your physics.

The Ferrari Effect is fact. As much so as it follows directly from Newton's Laws. To dismiss that, is to dismiss the basis of your physics.

Not much luck in deriving a flat earth.

This is from what I understand by looking into these definitions of flat and curved in geometry, I was pointed to this after asking about it and it seems it does in fact show Earth is round in GR.

I still claim that GR has nothing to do with "making the earth round". The curvature of the spacelike component of spacetime simply has the effect of increasing its diameter about 4 mm over the diameter in Euclidean space.

And please don't forget that the Ferrari Effect is nothing more than a farce, taken from an intentionally nonsense video to assist students to put some thought into what they believe.

Quote from: AltSpace on September 24, 2017, 08:08:09 PM

The Ferrari Effect

The Ferrari Effect is the effect of visualizing a flat plane as being a spheroid due to the curvature of aether (space-time dimensions). This was a prediction made by the philosopher Leo Ferrari that is currently a major concept in the Davis Relativity Model.

You do need to learn a little more about Dr. Leo Charles Ferrar and the Ferrari Effect. Just watch this and learn all about it.

AMAZING! Dr. Leo Charles Ferrari PROVES FLAT EARTH...

See more in AMAZING! Dr. Leo Charles Ferrari PROVES FLAT EARTH, These are clearly men of science, they can't be wrong - right?

Sure, it's interesting looking at the effects and tests of non-Euclidean spaces, but it it totally irrelevant to either the shape of the earth or  with how it looks.

The Ferrari Effect is fact. As much so as it follows directly from Newton's Laws. To dismiss that, is to dismiss the basis of your physics.

Rubbish!

The Ferrari Effect is fact. As much so as it follows directly from Newton's Laws. To dismiss that, is to dismiss the basis of your physics.

No, the Ferrari Effect is dellusional nonsense.

It relies upon facts only assured under Euclidean geometry, yet applies them to non-Euclidean geometry.
It conflates trajectories and shapes.
It appeals to gravitationally bound paths as straight lines, but then rejects them as not being straight, except for orbits.

I still claim that GR has nothing to do with "making the earth round". The curvature of the spacelike component of spacetime simply has the effect of increasing its diameter about 4 mm over the diameter in Euclidean space.

Yes, from a spherical Earth in Euclidean space, being the same geometry in the GR conception. If you have a mass, a large mass, and you throw it out into space, it will form into a sphere in GR, just like in Newtonian Gravitation, it is why the Earth is Round according to REers.

Quote from: rabinoz on September 24, 2017, 09:19:41 PM

Quote from: AltSpace on September 24, 2017, 08:08:09 PM

The Ferrari Effect

The Ferrari Effect is the effect of visualizing a flat plane as being a spheroid due to the curvature of aether (space-time dimensions). This was a prediction made by the philosopher Leo Ferrari that is currently a major concept in the Davis Relativity Model.

You do need to learn a little more about Dr. Leo Charles Ferrar and the Ferrari Effect. Just watch this and learn all about it.

AMAZING! Dr. Leo Charles Ferrari PROVES FLAT EARTH...

See more in AMAZING! Dr. Leo Charles Ferrari PROVES FLAT EARTH, These are clearly men of science, they can't be wrong - right?

Sure, it's interesting looking at the effects and tests of non-Euclidean spaces, but it it totally irrelevant to either the shape of the earth or  with how it looks.

I have watched that, I don't see any mention of the 'Ferrari Effect' as it is used by Davis and me in the past. It is mostly just making a case for a flat earth to teach kids the dangers of deception and their potential (basically, don't believe whatever people tell you simply because you received it from them). While Ferrari did make the original Ferrari effect as a joke, it was with potential basis in GR, and it does with the space-time geodesics, but I have come to realize it does nothing to show Earth is flat.

Quote from: rabinoz on November 17, 2017, 11:23:39 PM

I still claim that GR has nothing to do with "making the earth round". The curvature of the spacelike component of spacetime simply has the effect of increasing its diameter about 4 mm over the diameter in Euclidean space.

Yes, from a spherical Earth in Euclidean space, being the same geometry in the GR conception. If you have a mass, a large mass, and you throw it out into space, it will form into a sphere in GR, just like in Newtonian Gravitation, it is why the Earth is Round according to REers.

Yes, if you have a large enough mass, without other significant forces acting on it, it will become a sphere.
But this isn't based upon geometry.

but I have come to realize it does nothing to show Earth is flat.

And that is a whole let better than most people here.
Good job.

Quote from: rabinoz on November 17, 2017, 11:23:39 PM

I still claim that GR has nothing to do with "making the earth round". The curvature of the spacelike component of spacetime simply has the effect of increasing its diameter about 4 mm over the diameter in Euclidean space.

Yes, from a spherical Earth in Euclidean space, being the same geometry in the GR conception. If you have a mass, a large mass, and you throw it out into space, it will form into a sphere in GR, just like in Newtonian Gravitation, it is why the Earth is Round according to REers.

Sure, "it will form into a sphere in GR, just like in Newtonian Gravitation" but it has nothing to do with GR or non-Euclidean geometry.

Large masses forming near-spherical shapes is simply a result of mass, material strength and gravitation, whatever the cause of the gravitation.

Quote

Quote from: rabinoz on September 24, 2017, 09:19:41 PM

Quote from: AltSpace on September 24, 2017, 08:08:09 PM

The Ferrari Effect

The Ferrari Effect is the effect of visualizing a flat plane as being a spheroid due to the curvature of aether (space-time dimensions). This was a prediction made by the philosopher Leo Ferrari that is currently a major concept in the Davis Relativity Model.

You do need to learn a little more about Dr. Leo Charles Ferrar and the Ferrari Effect. Just watch this and learn all about it.

AMAZING! Dr. Leo Charles Ferrari PROVES FLAT EARTH...

See more in AMAZING! Dr. Leo Charles Ferrari PROVES FLAT EARTH, These are clearly men of science, they can't be wrong - right?

Sure, it's interesting looking at the effects and tests of non-Euclidean spaces, but it it totally irrelevant to either the shape of the earth or with how it looks.

I have watched that, I don't see any mention of the 'Ferrari Effect' as it is used by Davis and me in the past.

No, there is no specific "mention of the 'Ferrari Effect' as it is used by Davis", but I believe that John Davis coined the term and linked it with GR to give an air of respectability to an otherwise baseless hypothesis. See:

The effect of viewing the earth and it appearing round is known as the Ferrari Effect, named after former Canadian Flat Earth Society President Leo Ferrari who first predicted this. This describes that effect.

And read: EINSTEIN'S RELATIVITY PROVES THE EARTH IS FLAT, May 23, 2016 JohnDavis.
Do you wonder that I am so against the way John Davis tries to use Leo Ferrari and Einstein's reputation to prop up his hypothesis?

It is mostly just making a case for a flat earth to teach kids the dangers of deception and their potential (basically, don't believe whatever people tell you simply because you received it from them). While Ferrari did make the original Ferrari effect as a joke, it was with potential basis in GR, and it does with the space-time geodesics, but I have come to realize it does nothing to show Earth is flat.

I guess you could say that, "it was with potential basis in GR, and it does with the space-time geodesics".
That link was put in by the team that scripted the video, including Dr. Leo Charles Ferrar, purely to provide some pseudo-scientific justification to their idea that GR could bend light to make a flat earth appear as a Globe from space.

Of course, GR does predict that mass will bend light but only by about 1.75 sec of arc very close to the massive sun.
In fact Newtonian Gravitation also predicted that mass would bend light, but only by half as much as GR did because it does not include time dilation near a massive body.
To complicate matters, Einstein made a mistake (yes he was fallible) in his original calculations and ended up with the same value.
I don't know for sure if it was so much a mistake or simply because at that stage GR had not been formalised.

But, the bottom line is that the shape of the earth has nothing to do with curved GR and spacetime, other than GR being an explanation, not an ultimate cause, of gravitation.

And just remember that Dr. Leo Charles Ferrari was not a physicist or astronomer, but a philosopher and a noted Saint Augustine scholar. It might be worth reading this, even though it is a very non-flat earth source:

Leo Ferrari
Leo Charles Ferrari (December 8, 1927 – October 7, 2010) was a St. Thomas University philosophy professor, noted Saint Augustine scholar, and founding member of the parody organization Flat Earth Society of Canada.
Flat Earth Society activities
Leo Ferrari was a founding member and head of the satirical Flat Earth Society of Canada, later renamed the Flat Earth Society (FES).
In Ferrari's writings in support of the FES and the Flat Earth, he attributed everything from gender to racial inequality on the globularist and the Spherical Earth model. Ferrari even claimed to have nearly fallen off "the Edge" of the Earth at Brimstone Head on Fogo Island.
Ferrari was a key figure in the 1990 flat earth "documentary", In Search of the Edge. In the accompanying study guide, Ferrari is outed as a "globularist," someone who believes the earth is spherical. The intent of the film was to promote critical thinking about media by "[attempting] to prove in convincing fashion, something everyone knew to be false."

Ferrari used the flat earth in the video for no other reason than that is was something that, "something everyone knew to be false."
And some flat earthers haven't woken up to the joke yet! Look at: The (other) Flat Earth Society Wiki, Leo Ferrari,
though Eric Dubay author of The Atlantean Conspiracy speaks and writes very scathingly about Leo Ferrari and the FES. See:And The Atlantean Conspiracy, The Flat Earth Society is Controlled Opposition!.

Sure, "it will form into a sphere in GR, just like in Newtonian Gravitation" but it has nothing to do with GR or non-Euclidean geometry.

That doesn't make any sense, but alright, I'll assume you have some thought out reasoning behind what you mean here and just leave it at that.

Quote from: rabinoz on November 18, 2017, 02:32:04 PM

Sure, "it will form into a sphere in GR, just like in Newtonian Gravitation" but it has nothing to do with GR or non-Euclidean geometry.

That doesn't make any sense, but alright, I'll assume you have some thought out reasoning behind what you mean here and just leave it at that.

Sorry, i can't see the problem. Essentially when an object gets over a certain size the gravitation forces are strong enough exceed the yield strength of the materials and to pull the object towards the shape with the lowest gravitational potential energy.

Here is a bit of an earlier post on the "potato limit" as it is called:

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
This sort of thing

Quote from: Charles H. Lineweaver & Marc Norman

The Potato Radius: a Lower Minimum Size for Dwarf Planets
Summary: Gravitational and electronic forces produce a correlation between the mass and shape of objects in the universe. For example, at an average radius of ~ 200 km – 300 km, the icy moons and rocky asteroids of our Solar System transition from a rounded potato shape to a sphere. We derive this potato-to-sphere transition radius -- or “potato radius” -- from first principles. Using the empirical potato radii of asteroids and icy moons, we derive a constraint on the yield strength of these bodies during their formative years when their shapes were determined. Our proposed ~200 km potato radius for icy moons would substantially increase the number of trans-Neptunian objects classified as “dwarf planets”.

From The Potato Radius: a Lower Minimum Size for Dwarf Planets.

The limit for rocky planets is only about 300 km, so you see the Flat Earth cannot countenance Newtonian Gravitation, no matter how well proven!

You say this:

I still claim that GR has nothing to do with "making the earth round".

And then say this:

Sure, "it will form into a sphere in GR, just like in Newtonian Gravitation" but it has nothing to do with GR or non-Euclidean geometry.

All I see here is you saying, "According to GR, you are right, large enough mass's with little to no extra forces acting upon them will form to near-spherical round mass's, but GR has nothing to do with making the Earth round"
But surely it would, as like you say here:

Essentially when an object gets over a certain size the gravitation forces are strong enough exceed the yield strength of the materials and to pull the object towards the shape with the lowest gravitational potential energy.

Which is a near-sphere in GR and Newtonian Gravity (we can presume they are one and the same since they would refer to the same phenomenon), so surely, GR/Gravity has a lot to do with "rounding" out the Earth, and keeping it quite round.
So, it seems I am lost on your statement that I still claim that GR has nothing to do with "making the earth round".
I know other forces would come into play but Earth is round according to REers and modern science because of Gravity/GR, and slightly oblate because of other gravitational influences and rotation.

I know other forces would come into play but Earth is round according to REers and modern science because of Gravity/GR, and slightly oblate because of other gravitational influences and rotation.

I don't think we really disagree. I just want to stress the GR causes the near spherical shape because the curvature of spacetime is the cause of gravitation.

The curvature of space itself does not have any effect on the shape or the appearance of the shape - there is no Ferrari effect.

There is nothing wrong the Ferrari effect except folks here misunderstanding it.

There is nothing wrong the Ferrari effect except folks here misunderstanding it.

And it being fundamentally flawed, with those promoting it misunderstanding it.