Mac's Final Relativity Thread

[MacM]

Where? Quote my lie. GIVE POST NUMBER, as I do your lies and flip flopping (again below in part but more links were given earlier.)

Note the self contradiction (flip flopping) even in one MacM post,908, (red text directly contradicts the green text) and the admitted “frequent qualified” use of "Spatial Contraction." Sometimes asserting it does not exist and other post asserting it can only be physically real in the frame that previously had acceleration (never in the “resting frame”). Covering all possible point of views in only one post sure seems like “flip flopping” to me.
Read post 920 for fuller details. This post mainly concerns MacM's flip flopping. For example post 893, reference above is quoted in post 920, etc. I do not want to do too much double posting of the documetation already given in post 920 again - just enough to again prove MacM's skill as a flip flopper.

I again note MacM can only ASSERT, NOT DOCMUMENT, that I lie or flip flop.

Billy T if you don't choose to address relativity get lost. I will not dcontinue to repeatedly correct your distortions and lies. Otherss can see what has been posted by us both. No need for me to recite.

 

[Montec]

Hello MacM, et al.

It should be pointed out that relative velocity (which is a vector) should not be used in SR calculations. However, relative speed works very well as long as you understand SR's limitations when applied to the real world. As an example there is zero relative velocity (no change in distance) between an object in a perfect circular orbit and the central mass about which it orbits. However, there is a relative speed difference.

So the directions multiple objects take play no part in SR calculations. Only relative speed through the cosmos will work. Choosing which object is faster or slower is the hard part unless (as in the above example) you can use common sense to help you out. (Relative speed to the CMB radiation would work I think)

 

[MacM]

Hello MacM, et al.

It should be pointed out that relative velocity (which is a vector) should not be used in SR calculations. However, relative speed works very well as long as you understand SR's limitations when applied to the real world. As an example there is zero relative velocity (no change in distance) between an object in a perfect circular orbit and the central mass about which it orbits. However, there is a relative speed difference.

So the directions multiple objects take play no part in SR calculations. Only relative speed through the cosmos will work. Choosing which object is faster or slower is the hard part unless (as in the above example) you can use common sense to help you out. (Relative speed to the CMB radiation would work I think)

Hello Montec,

Thanks for your contribution.

I need however to point out that I have historically shown that in the case of GPS what you suggest doesn't work. Computing time loss due to speed:

That is if you take orbit speed and subtract earth's surface rotational speed
and use that as relative velocity SR math produces a -5.8us/day time loss.

That is an incorrect value. The correct value is -7.2us/day and can be computed by orbit speed to the ECI frame of reference (Earth Center Inertial)

The earth's surface speed to the ECI could be computed for dilation and subtracted from the orbit dilation value to get a net dilation.

But the surface speed not only produces less than 1% of the affect but isn't used because due to gravity and the shape of the earth (Oblate Sphereoid) all clocks at sea level tick the same regardless of latitude. That is a clock at the north or south pole tick the same as a clock at the equator.

So the fact is GPS voids SR altogether and uses a form of Lorentz Relativity by using a preferred frame where the inherent reciprocity of a relative velocity view is prohibited. That is you cannot now claim the orbiting clock is at rest and the ECI has orbit velocity. Only one clock can have "Actual Velocity" and not mere "Relative Velocty" between clocks.

 

[Billy T]

... Only one clock can have "Actual Velocity" and not mere "Relative Velocty" between clocks.

Congratulations on your new terminology. "Actual Velocity" is better than your old "real velocity" and "Relative Velocity" is better than your old "illusionary velocity." "Better" in the sense that these new terms hid the nonsense more deeply.

As Montec correctly pointed out, only the speed of separation between two inertial frames is important for relativistic effects.
If frame A is separating from frame B at speed S, then frame B is separating from frame A at speed S also.*

Thus there is reciprocity in the relative velocity or speeds of separation so there is reciprocity in the strange SR effects, which are due ENTIRELY to DESCRIBING events (such as clock tick rates) and lengths of another frame in terms of the seconds and meter sticks of your frame. Neither the "other frame", nor your frame, (which is the "other frame" for them.) has any physical change, as you falsely assert, without any evidence, as that would require even quantum THEORY to change with speed.

BTW1: You cannot refute Montec by discussing a non-inertial frame (on orbiting the Earth). SR only applies to inertial frames. One can make association between the instantaneous conditions of a an orbiting object’s rotating frame and the tangential linear velocity frame with the same speed; however, applying those association to the orbiting frame can introduce false forces, like the “Coriolis force” effect, which is due to working in a rotational frame and other effects due to describing things in a non-inertial frame.

BTW2: I note that you still only assert that I lie about your POV. – You do not give any specific examples with the post number of them as I have done many times about your flip flopping and lying. So yes I agree that the readers of this thread can correctly judge who is documenting and who is just asserting.

-----------------
*Montec, also speaks of one frame being faster, but that that concept requires still a third frame. For some "third frames" A is faster than B and for other "third frames," B is faster than A. Thus, there is no sense to the concept that A is inherently faster than B or its converse. The choice of which is "faster" depends on the arbitary choice of the third frame.

 

[MacM]

Congratulations on your new terminology. "Actual Velocity" is better than your old "real velocity"

About time you ctually read something. I've used this term for years.

and "Relative Velocity" is better than your old "illusionary velocity."

Considering I have never EVER calledany veloicuty "Illusionary" That is your own fabrication nonsense. Like I have corrcted you numerous times for saying that and pointedcout the "Illusion" is the time dilation produced by mere relative veloicty. But you continue to spread you lies.

"Better" in the sense that these new terms hid the nonsense more deeply.

The nonsesne is all your. The guy that say "Nothing ever changes physically"; which leavestime dilation in the twins example without any physical cause to have a permenent affect. You really need to work on that concept.

As Montec correctly pointed out, only the speed of separation between two inertial frames is important for relativistic effects.
If frame A is separating from frame B at speed S, then frame B is separating from frame A at speed S also.*]/quote]

But speed between two frames says nothing about actual time dilation between them. As I have proven numerous times the case of two clocks boh launching from a common rest frame and then re-uniting shows that their relative velocity to each other is NOT supported by emperical data.

What is supported by emperical dfata is the differential between each of thier respective time dilations to the common rest frame. What they see DURING relative veliocty IS only illusionary time dilation and causes no permanent change once they re-unite in a common inertial frame.

Now stop waffeling and deal with that fact.

Thus there is reciprocity in the relative velocity or speeds of separation so there is reciprocity in the strange SR effects, which are due ENTIRELY to DESCRIBING events (such as clock tick rates) and lengths of another frame in terms of the seconds and meter sticks of your frame. Neither the "other frame", nor your frame, (which is the "other frame" for them.) has any physical change, as you falsely assert, without any evidence, as that would require even quantum THEORY to change with speed.

Of course there is reciprocity. I have said so numerous times but I correctly have pointed out it is illusionary and causes no permanent time dilation. It is not REAL time dilation. So tell us something we don't all know.

BTW1: You cannot refute Montec by discussing a non-inertial frame (on orbiting the Earth).

Ah. Glad to see you take the bait. It happens the issue of non-inertial is not clearly resolved.

1 - If indeed it is non-inertial then clearly GPS isn't using SR. I have said GPS doesn't use SR but for different reasons and James R and others objected and point to Neil Ashby a relativist that publishes claiming GR and SR are both used in GPS.

2 - Then those that claim orbit is under constant acceleration and hence is non-inertial reject SR being used to compute orbit time dilation.

3 - Free-Fall in a gravity field IS an inertial frame.

FYI: Orbit is under EEP in constant Free-Fall and hence has by meny been declared as an inertial condition.

You just aren't as smart as you think you are and don't understand things as they are but try to mold them to what you think they should be. i.e. You are clueless about physics.

SR only applies to inertial frames. One can make association between the instantaneous conditions of a an orbiting object’s rotating frame and the tangential linear velocity frame with the same speed; however, applying those association to the orbiting frame can introduce false forces, like the “Coriolis force” effect, which is due to working in a rotational frame and other effects due to describing things in a non-inertial frame.

Again tell us something we don't know. I have had to argue many time with folks like you that SR can be used under accelerating or non-inertial conditions. However, in GPS they are NOT integrating a changing vector speed (velocity) speed is constant and is inertial in that it is under balanced force conditions of Free-Fall.

BTW2: I note that you still only assert that I lie about your POV. – You do not give any specific examples with the post number of them as I have done many times about your flip flopping and lying. So yes I agree that the readers of this thread can correctly judge who is documenting and who is just asserting.

Since I have responded to this many times I let my resopnses stand because you have been firmly rebutted. Your continued assertion therefroe can be labled nothing but a deliberate lie.

*Montec, also speaks of one frame being faster, but that that concept requires still a third frame. For some "third frames" A is faster than B and for other "third frames," B is faster than A. Thus, there is no sense to the concept that A is inherently faster than B or its converse. The choice of which is "faster" depends on the arbitary choice of the third frame.

Posted by Montec:"Choosing which object is faster or slower is the hard part unless (as in the above example) you can use common sense to help you out.

Posted by Billy T:"The choice of which is "faster" depends on the arbitary choice of the third frame.

Double talk, it most clearly does not. Nothing in Montec's comment suggests a thrid frame or makes a third frame necessary. Let Montec speak for himself and stop trying re-write what others post. You have not done very well trying to re-write mine.

 

[Billy T]

... 3 - Free-Fall in a gravity field IS an inertial frame. ...

Only true if there is no rotation. To keep antennas pointed towards the Earth, I think GPS rotates 360 degrees each orbit.

One can tell if they are in an inertial frame or not with a bucket of water. If the water surface is not a plane, then you are rotating and not in an inertial frame. "Artificial forces"* are present (Coriolis "force").

You can also detect the rotation with a gyroscope. Both are means of determining if you are in a true inertial frame or not even if inside a sealed room.

Of course, if you can look out, it is also easy to see in you are rotating and thus non-inertial even if in free fall, like orbiting the Earth.

SUMMARY: AGAIN YOU ERROR - GPS, or any earth orbiting satellite, is not in an inertial frame.
---------
*Called “artificial” as there is no "equal and opposite" reaction force as all real forces always have.

 

[MacM]

Only true if there is no rotation. To keep antennas pointed towards the Earth, I think GPS rotates 360 degrees each orbit.

One can tell if they are in an inertial frame or not with a bucket of water. If the water surface is not a plane, then you are rotating and not in an inertial frame. "Artificial forces"* are present (Coriolis "force").

You can also detect the rotation with a gyroscope. Both are means of determining if you are in a true inertial frame or not even if inside a sealed room.

Of course, if you can look out, it is also easy to see in you are rotating and thus non-inertial even if in free fall, like orbiting the Earth.

SUMMARY: AGAIN YOU ERROR - GPS, or any earth orbiting satellite, is not in an inertial frame.
---------
*Called “artificial” as there is no "equal and opposite" reaction force as all real forces always have.

Gee Einstein has been quoted as saying (paraphrased) Light is only invariant in absence of a gravity field but SR is still useful if gravity is weak enough such that it can be ignored.

Likewise the "Tidal" forces of gravity around a massive body are sufficiently weak as to be ignored and orbit is considered as an inertial condition.

I assume you do know what a tidal force is on an object in orbit don't you?

Perhaps you need to go back to school.

 

[phyti]

MacM post 1000';

That's not the same problem. The 981 post stated "as he returns".
In this case B accelerates as A passes, but the instantaneous acceleration
removes the real world fact that while he is, A is putting some distance between them.
B will have to move faster than A to catch up, thus his clock will accumulate less time than A's clock for this part of the trip (since meeting).
I'm getting off the bus here, because it's going in circles!
You guys have fun.

 

[Billy T]

... I assume you do know what a tidal force is on an object in orbit don't you? ...

Yes, I do but your are confused if you think the section of a parabola the surface of the water in a bucket orbiting the Earth takes is due to the tidal forces. They are present but as the dimensions of the bucket are small and tidal forces decrease as the cube of the separation from the center of the Earth, it is the centripetal acceleration that keeps the orbiting object for being in an inertial frame. That goes as rW^2, not as the tidal force's inverse cube of r, where W is the rotational speed (radians/sec) and r the distance from the center of rotation.

One could achieve exactly the same orbit in deep space, far from any gravity with a small thruster constantly thrusting perpendicular to the velocity towards a fixed point. (Put a ping pong ball there if that is too hard a concept for you.) Then there is ZERO tidal force but the orbit and centripetal force is unchanged. Now, with the thrusters in constant operation it is more obvious that the IDENTICAL orbit is NOT inertial.

Just because the speed is constant, does not mean the acceleration is zero. The direction of the velocity is constantly changing. Thus the velocity is constantly changing. If the velocity is changing you are NOT in an inertial frame.

But your bringing in tidal force was a nice duck and weave.

SUMMARY: Your statement that object in free falling orbit, like GPS satellite, is in an inertial frame is simply False. But don't give up - you are good* at defending false claims.
-------------------
* Well at least stubborn.

 

[MacM]

MacM post 1000';

That's not the same problem. The 981 post stated "as he returns".
In this case B accelerates as A passes, but the instantaneous acceleration
removes the real world fact that while he is, A is putting some distance between them.
B will have to move faster than A to catch up, thus his clock will accumulate less time than A's clock for this part of the trip (since meeting).
I'm getting off the bus here, because it's going in circles!
You guys have fun.

Ah. You have missed the point. He need not catch up perse' but merely join him in the same frame. Once he reaches the same veloicty they could be a l year apart but they are still at common rest in "A's" frame if they both are inertial.

 

[MacM]

Yes, I do but your are confused if you think the section of a parabola the surface of the water in a bucket orbiting the Earth takes is due to the tidal forces. They are present but as the dimensions of the bucket are small and tidal forces decrease as the cube of the separation from the center of the Earth, it is the centripetal acceleration that keeps the orbiting object for being in an inertial frame. That goes as rW^2, not as the tidal force's inverse cube of r, where W is the rotational speed (radians/sec) and r the distance from the center of rotation.

Clearly you do NOT know what tidal forces in orbit are.

One could achieve exactly the same orbit in deep space, far from any gravity with a small thruster constantly thrusting perpendicular to the velocity towards a fixed point. (Put a ping pong ball there if that is too hard a concept for you.) Then there is ZERO tidal force[/color=red] but the orbit and centripetal force is unchanged. Now, with the thrusters in constant operation it is more obvious that the IDENTICAL orbit is NOT inertial.

The only thing obvious is that you do NOT know what a tidal force in orbit is. Thanks for making this ever so easy.

Just because the speed is constant, does not mean the acceleration is zero. The direction of the velocity is constantly changing. Thus the velocity is constantly changing. If the velocity is changing you are NOT in an inertial frame.

I do believe I have already aid this.

But your bringing in tidal force was a nice duck and weave.

Better yet it is going to PROVE you are a fraud. You don'ty even know what such tidal forces are.

SUMMARY: Your statement that object in free falling orbit, like GPS satellite, is in an inertial frame is simply False. But don't give up - you are good* at defending false claims.
-------------------
* Well at least stubborn.

Since this isn't something I have made up but is accepted fact in much of modern science you are going to regret this little episode of distort and lie.

Here let me educate you once again.

http://www.daviddarling.info/encyclopedia/T/tidal_force.html

The balance of gravity only exists at a finite curved line around the planet. Any object with tangential length has gravity pulling at each end at an angle since gravity is toward the center of the earth. Hence there exists a compression force over the length of the object. Further any mass at less radius than the gravity balance point is being pulled inward. Mass at greater radius from earth wants to move outward. It is only held on orbit as a net pull-push across it's domain.

That is why it is micro-gravity not zero gravity. Zero gravity is strictly hypothetical and cannot be realized for any object other than a singularity.

More telling is the fact that you don't even understand that to force an orbital motion using external rocket force leaves you feeling a centrifugal force not micro-gravity. Shsssh! Ignorance really irks me.

Now you know thanks to MacM. Don't forget to say thank you.

 

[Billy T]

MacM I know quite a lot about gravity gradients (tidal forces). I have helped design gravity gradient stabilized satellites.* and yes there is almost always a compressive force along the orbit but it is small compared to the force due to the gravity gradient which as I said falls off as the inverse cube. That is why to show the orbit is not inertial I replaced it with an IDENTICAL orbit far for any gravity field. (That identical orbit being achieved in post 1009 with a small continuously and constant magnitude thrusting rocket motor with thrust perpendicular to the velocity direction.)

Thus your introduction of gravity gradient is a duck and weave, unrelated to the question about a circular orbit being inertial or not. It is NOT. Your statement that it is continues FALSE. The IDENTICAL orbit, far from ANY gravity, with rocket transversely thrusting clearly is not inertial. Again:

If the velocity is changing, the frame is NOT inertial even if the speed is constant. Any orbit with velocity continuously changing, even if only direction, is NEVER an inertial orbit, but an accelerating orbit.
----------------
*A satellite can be made to always point it antennas towards the Earth with ZERO expenditure of energy. This is done by dividing the mass into two parts separated by a boom. Initially the mass closer to the center of the Earth will be pulled down more towards the center of the earth than the other mass as it is in a stronger gravity field.

Unfortunately the boom will just oscillate back to the original angle wrt the vertical. The typical oscillation will be very slow, very long period so there will be very little damping provided by the flexing of the boom. We made at least half a dozen of these gravity gradient satellites at JHU’s Applied Physics Lab. where I worked for 30 years. The trick for stability (damping of the oscillation) is to include some high hysteresis magnetic material in the boom. With each oscillation the trip around the hysteresis loop removes energy and unlike boom flexing, it does not matter how slowly the boom oscillates, - each cycle removes energy. (As I recall a relatively fixed fraction of the energy of oscillation.) I have forgotten more about gravity gradient satellites than you will ever know.

But again, this gravity gradient nonsense YOU introduced is just your duck and weave attempt to avoid admitting your error. Any circular orbit, with or without gravity making it circular**, is an ACCELERATED orbit, NOT an inertial orbit.

----------
**Why orbit is circular is unimportant. The circular orbit could be a weight with rope swinging it around a pivot point in deep space and that is not an inertial orbit either.

NO CIRCULAR ORBIT IS INERTIAL.
YOU ARE SIMPLY WRONG AND EITHER TOO IGNORNATE OR TOO FOOLISH TO ADMIT YOUR ERROR.

*Interestingly the first gravity gradient satellites were made by accident. A bundle of several thousand long thin wires were tossed out in orbit in low Earth orbit. Their binder would sublime in the vacuum of space so they would become a dense cloud that radio waves could be bounce off of for communication. (Each wire was half a wavelength long.) It seemed like a cheap idea, but they never were found. – They did not reflect – they had become aligned with the ends all pointing towards the center of the earth – tiny gravity gradient oriented satellites! They were in relatively low Earth orbit and have all burned up long ago.

 

[James R]

Billy T:

When talking about orbits it is vitally important to specify whether you're using a flat-space model with Newtonian gravity or a curved-space model such as general relativity.

In a Newtonian world, gravity is a force. An orbiting satellite in Newton's world is constantly accelerating towards the centre of the Earth due to the centripetal gravitational force acting on it. Since it is always subject to an external net force its motion is not inertial.

In a general relativistic world, gravity is not a force but an effect that is apparent due to curved spacetime. An orbiting satellite in Einstein's general relativistic world is in gravitational free-fall. It does not accelerate as it orbits because it is simply following a geodesic (the "shortest path" in the curved spacetime around the Earth). It's motion in this case is inertial because it has no forces on it.

The starting point for Einstein's development of general relativity from the special theory was his realisation that gravitational force and so-called pseudoforces due to viewing things from a non-inertial frame of reference are indistinguishable. From this idea he formulated the Equivalence principle.

Under general relativity, all reference frames that are in free-fall under gravity are considered to be inertial frames. The problem to be solved then is how to "connect" distance free-falling frames together. For example, objects at different heights above the Earth's surface appear to fall at different rates due to gravity. If gravity is not a force, then how can an object apparently speed up as it falls, even though it is not subject to any force? The solution to such problems is curved spacetime. In the falling object case, we then realise that the Earth's surface is not itself an inertial reference frame. It is not the falling object that has the problem; it is the observer standing on the ground. The observer is non-inertial in that case (note: this has nothing to do with the rotation of the Earth, which is a separate matter).

In summary, when MacM states that orbiting objects are moving inertially, he is actually using the general theory of relativity, even if he is unwilling to admit that. But he is technically correct that orbital motion is inertial, and you are technically wrong, provided that you are both talking in the context of general relativity.

Despite this, MacM's statements about the GPS are still full of nonsense. Even in general relativity there are still no "preferred" reference frames, and the GPS system does not require that we use any such "preferred" frame, despite any bleating by MacM to the contrary.

The actual calculation of the "tick rate" of an orbiting clock relative to a ground clock is complicated. The entire calculation can, of course, be done using general relativity. If we take the final result of such a calculation, it can be understood conceptually as having a number of separate contributions. These include a contribution from the satellite's tangential speed relative to the ground (which is akin to special relativistic time dilation), a contribution from gravitational time dilation due to the satellite being higher up in a curved-space gravity well, and another contribution due to the Earth's rotation. The major effect is the gravitational time dilation, which acts in the opposite direction to the relative velocity (special relativistic analogue) effect.

MacM cannot understand any of this, naturally. He will tell you that I assert that BOTH special relativity AND general relativity must be applied separately. That is not the case, since special relativistic effects are already built into general relativity. They just provide a convenient handle on which to hang a conceptual understanding of the contributions to the net time dilation. MacM cannot get to grips with even a conceptual understanding of GPS, let alone handling the mathematics of general relativity required to solve the numerical problem. He remains stuck in a fantasy of preferred frames, half-arsed half-applied relativity and other MacM nonsense.

MacM has admitted that he thinks general relativity is "better" or superior to special relativity, in that it is somehow more accurate. He does not understand that SR is a subset of GR. He won't commit to just how accurate he thinks GR is. He has a gut feeling that there must be something wrong with GR because it's Einstein's theory and Einstein was wrong about SR, but since in reality MacM can't make head or tail of GR he is always vague about exactly what the problems with GR might be. All he is sure of is that Einstein couldn't possibly be right and that he, MacM, is a genius far superior to Einstein.

 

[Billy T]

To James R:

Thanks for your post 1013 discussion. Yes, I am speaking only in Newtonian terms, or perhaps with some SR thrown in. I am sure that MacM also cannot do otherwise as that requires understanding of GR. (tensor math)

I know that gravity is not a real force in terms of GR, but tend to ignore that fact as unlike most (if not all) other pseudo forces (such as the Coriolis "force") gravity does have the Newtonian "equal and opposite" force so I tend to treat gravity as if it were a "real force." (I.e. the Earth falls up to meet the falling brick.)

I am quite sure that MacM cannot even read correctly the tensor equations of GR. That I can probably still do (E.g. I still know the hidden meaning in repeated subscripts, so can read that summation correctly, etc.) but never was I able to do anything more than follow derivations in that tensor math - not able to develop any independently.

 

[MacM]

To James R:

Thanks for your post 1013 discussion. Yes, I am speaking only in Newtonian terms, or perhaps with some SR thrown in. I am sure that MacM also cannot do otherwise as that requires understanding of GR. (tensor math)

I know that gravity is not a real force in terms of GR, but tend to ignore that fact as unlike most (if not all) other pseudo forces (such as the Coriolis "force") gravity does have the Newtonian "equal and opposite" force so I tend to treat gravity as if it were a "real force." (I.e. the Earth falls up to meet the falling brick.)

I am quite sure that MacM cannot even read correctly the tensor equations of GR. That I can probably still do (E.g. I still know the hidden meaning in repeated subscripts, so can read that summation correctly, etc.) but never was I able to do anything more than follow derivations in that tensor math - not able to develop any independently.

I'm not going to bother correcting either you or James R. I was glad to see James actually take exception to your statements. James R is wrong as to my basis for claiming orbit as inertial. It is inertial in that there are no acceleration forces felt.

Now that may be due to GR or in fact even Newtonian gravity. The angulr acceleration is NOT the same as normal acceleration. Time dialtion is a fuction of velocity achieved via acceleration and not accelertion perse'.

In orbit there is no change in "Speed" only in vector. In your post you suggested it would be the same if you used rocket thrusters to make a circle in deep space.

That is absolutely false. In such case one would be subjected to centrifugal forces or the force of angular acceleration.

Free-Fall is a condition "Free" of external forces. In orbit around a massive body you have a balance of forces just as you have a balance of forces in normal free-fall.

As far as you two deciding what MacM knows or understands that is outright bullshit.

Finally if you knew what "Orbit Tidal Forces": were then you would have stated so properly in the first instance instead you blew it and then come back pretending to be an expert.

We have your number by now so save your breath.

 

[MacM]

For anyone wanting to actually know the truth:

http://www.ion.org/search/view_abstract.cfm?jp=p&idno=754

Title: Successful GPS Operations Contradict the Two Principles of Special Relativity and Imply a New Way for Inertial Navigation - Measuring Speed Directly

Author: Ruyong Wang

Meeting: Proceedings of the IAIN World Congress and the 56th Annual Meeting of the Institute of Navigation


********************** Extract ********************

Therefore, the ECI frame is a preferred frame near the earth.

************************************************

http://www.jamesphogan.com/bb/bulletin.php?id=140

****************************************Extract **************************
Therefore, the ECI frame is a preferred frame near the Earth, contradicting the principles of there being no
preferred frame, and of the constancy of the velocity of light

 

[Billy T]

MacM - Let’s put some numbers in to show that the radial gravity gradient (force along the radial direction) is significantly larger than the tangential gravity gradient or what you called “tidal force” in post 1007 and explain in post 1009* as acting as compression along the orbital direction:

Working in convenient dimensions (so mG = 1 and Earth radius is unity also) and assuming an orbit of 0.1 altitude (Distance from center of the earth of 1.1 earth radii.), then even with a very large spherical satellite of radius 0.002 we have the front and trailing parts of the sphere 0.001 from the sphere center.

It is true, as you said, that the force on the front of the satellite (on the leading edge in its orbit) has a component directed towards the center of the satellite slightly compressing it. This in “track force” component is: F sin A. where the angle A = (0.001 / 1.1) radians. (Angle A is of course the tiny angular difference at the center of the Earth between satellite front and center.)

For such a small angle, the sin is the same as the angle in radians. The gravitational force, Fg, is mG/ {(1.1)^2] or in these convenient units F = 1.1^(-2) = 0.8264; So the compressive force, Fc, is only:
Fc = Fg A = 0.8264 x (0.001/1.1) = 0.000,7513 in “convenient units.”


Now let’s consider the force towards the center of the earth between top and bottom of the sphere, due to gravity being weaker on the top than the bottom (again in these convenient units):

F on top, Ft = (1.101)^(-2) & on bottom Fb = (1.099)^(-2) and difference, the radial force, Fr, trying to pull the satellite apart is

Fr = {1/1.099^2} - {1 / 1.101^2} = {1/ 1.2078} - {1/ 1.2122} = 0.8279509 – 0.8249456 = 0.003005

Thus the radial gravity gradient force is four times larger than the in orbit track force.

I.e. the ratio is (0.003005 /0.0007513) = 3.005/0.7513 = 4.0001

That is why what you call the “tidal force” (a tangential or in-track, gravity gradient force) is not even normally considered when calculating the Roche limit on how close the moon could have once been to the Earth without being broken into pieces.

--------------
*MacM in post 1009: “Any object with tangential length has gravity pulling at each end at an angle since gravity is toward the center of the earth. Hence there exists a compression force over the length of the object.”

 

[MacM]

MacM - Let’s put some numbers in to show that the radial gravity gradient (force along the radial direction) is significantly larger than the tangential gravity gradient or what you called “tidal force” in post 1007 and explain in post 1009* as acting as compression along the orbital direction:

Working in convenient dimensions (so mG = 1 and Earth radius is unity also) and assuming an orbit of 0.1 altitude (Distance from center of the earth of 1.1 earth radii.), then even with a very large spherical satellite of radius 0.002 we have the front and trailing parts of the sphere 0.001 from the sphere center.

It is true, as you said, that the force on the front of the satellite (on the leading edge in its orbit) has a component directed towards the center of the satellite slightly compressing it. This in “track force” component is: F sin A. where the angle A = (0.001 / 1.1) radians. (Angle A is of course the tiny angular difference at the center of the Earth between satellite front and center.)

For such a small angle, the sin is the same as the angle in radians. The gravitational force, Fg, is mG/ {(1.1)^2] or in these convenient units F = 1.1^(-2) = 0.8264; So the compressive force, Fc, is only:
Fc = Fg A = 0.8264 x (0.001/1.1) = 0.000,7513 in “convenient units.”


Now let’s consider the force towards the center of the earth between top and bottom of the sphere, due to gravity being weaker on the top than the bottom (again in these convenient units):

F on top, Ft = (1.101)^(-2) & on bottom Fb = (1.099)^(-2) and difference, the radial force, Fr, trying to pull the satellite apart is

Fr = {1/1.099^2} - {1 / 1.101^2} = {1/ 1.2078} - {1/ 1.2122} = 0.8279509 – 0.8249456 = 0.003005

Thus the radial gravity gradient force is four times larger than the in orbit track force.

I.e. the ratio is (0.003005 /0.0007513) = 3.005/0.7513 = 4.0001

That is why what you call the “tidal force” (a tangential or in-track, gravity gradient force) is not even normally considered when calculating the Roche limit on how close the moon could have once been to the Earth without being broken into pieces.

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*MacM in post 1009: “Any object with tangential length has gravity pulling at each end at an angle since gravity is toward the center of the earth. Hence there exists a compression force over the length of the object.”

Whoopie!. Irrelevant. You were unaware of tidal forces. You proposed using a rocket thruster and making a circle in space as being identical. IT IS NOT. You would feel forces of angular acceleration. In free-fall there are no such forces.

James R has also corrected you regrading inertial.

 

[MacM]

FOR THE RECORD:

We have all seen James R claim to have been knowledgeable about GPS and claim to have educated me and corrected me. When I have said he flip-flops he challenged me to post any such flip-flop.

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http://www.sciforums.com/showthread.php?p=843363&highlight=inertial+frame#post843363

#127

Posted by MacM:"If you use relative velocity between a clock at the earth's equator and an orbiting GPS clock to compute time dilation you get -5.8us/day loss due to relative velocity. That is incorrect.

The correct figure is -7.2us/day and is computed using orbit velocity referance the center of the earth the ECI frame (Earth Centered Inertial)."

Posted reply by James R:"Two different frames, two different results. No problem. The 5.8 figure is correct for the surface, and the 7.2 figure is correct for the centre of the Earth. So what?

It should be clear from his reply that he knew nothing about GPS. He doesn't even know that -7.2us/day is the correct answer or that you can't get a surface calculation based on surface rotational speed because all surface clocks at sea level tick in synch regardless of latitude.

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http://www.sciforums.com/showthread.php?p=821613&highlight=inertial+frame#post821613

#104

Posted by MacM:"You simply do not understand the differance between a velocity gamma calculation and SRT. GPS DOES NOT use SR. "

Posted by James R:"Right! It uses GR. Who ever said it used SR?"

Here he denies SR is used or that he ever said it was.

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But here he claims STR is used.

http://www.sciforums.com/showthread.php?p=813310&highlight=inertial+frame#post813310

#1

Posted by James R:"At this point, I can do no better than send readers who have not already been there to Neil Ashby's paper for a detailed accounting of str and gtr effects which are significant in the GPS system."

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http://www.sciforums.com/showthread.php?p=1266953&highlight=non-inertial#post1266953

#15

Originally Posted by zanket:"Let a lab be in free fall in an inertial frame “X”. A thrusting rocket moves freely within the lab, dragging a rope behind itself. The rope straddles the horizon of a black hole. The rocket hovers above the horizon.

Posted by James R:"Then the rocket must be accelerating constantly. The rope is attached to the rocket. The rest frames of both are non-inertial.

He tells Zanket that a rocket in orbit around a Black Hole is constantly accelerating and is a non-inertial frame.

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http://www.sciforums.com/showthread.php?p=908230&highlight=non-inertial#post908230

#37

Posted by Prosoothus:"Inertial force is the force that matter exerts on an object that is trying to change its speed or direction.

Posted reply by James R:"....I advise you to use the term "reaction force" in this context, because physicists use the term "inertial force" to refer to certain forces on objects in non-inertial reference frames.

Here he tells Prosoothus that "change in speed or direction" is non-inertial.

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But here:

http://www.sciforums.com/showthread.php?p=2356733#post2356733

#1013

Posted by James R above to Billy T:"It does not accelerate as it orbits because it is simply following a geodesic (the "shortest path" in the curved spacetime around the Earth). It's motion in this case is inertial because it has no forces on it.

At other times James has claimed that orbit is non-inertial because it is under constant acceleration.

I have frequently stated that it is inertial if there is no F=ma or centrifugal/centriputal forces on it but James quickly attacks with "But you don't understand physics centrifugal force doesn't exist, it is a ficticious force." But here he flip-flops and orbit is not an accelerating frame and there are no forces on it hence it is inertial.

His entire conduct over these past few years has been to object to anything I have said and to post distorted versions of my posts or to flip-flop his view just to be on the attack or lies so much he can't remember what he has said in the past.

He attempts to divert the thread from the issue raised to a peraonal attack on me. Well his brown smelly stuff isn't sticking to the wall this time.

I on the other hand have been consistant (right or wrong) and have never changed my view.

To him that is ignorance or an inability to learn. Which boils down to I've told you about relativity and you reject it therefore you are ignorant or can't learn.

Well frankly I'm not ignorant and I don't need to learn. He needs to learn. He needs to learn that relati ity is NOT law but theory and many NOT just MacM have raised issues about it which receive the same treatment as I have. It matters not what education or experience a physicist has if he turns on Einsten's world he is labled a Crank, Crakpot or worse.

If he ever posts anything other than dogma, rhetoric or appeal to authority that has some real physics content then perhaps I might have changed my mind but not based on his trash responses.

He nor Billy T have posted a diagram of how the twin paradox is resolved. I have posted diagramed examples of time dilation or spatial contraction.

They have not rebutted the conclusions. Oh they make high faluting or technical sounding replies but on close inspection they say nothing. i.e. - Billy T's "Nothing changes (then qualified) in their own frames".

But refuses to acknowledge that frame to frame there must be dilation otherwise there can be no physical change in the twins age unless there is physical cause or change.

Or James R's "But SR says".

When confronting a theory quoting the theory is not a rebuttal of the allegation against it.

We are still waiting for Billy T or James R to post a diagram shoiwng the resolution of the twin paradox.

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I really hope these will suffice because I hate wasting time tearing people down but when they lie and try to tear me down then it is time for turn about is fair play.

 

[James R]

MacM:

FOR THE RECORD:

We have all seen James R claim to have been knowledgeable about GPS and claim to have educated me and corrected me. When I have said he flip-flops he challenged me to post any such flip-flop.

How impolite. I posted in support of your position to clarify your argument with Billy T, and you respond not by thanking me but by falsely pointing out supposed errors of mine that are years old.

And you're wrong or you've misunderstood, as usual. And quoted me out of context. How rude.

Here he denies SR is used or that he ever said it was.

Right. The GPS system requires that general relativity be used to get the full picture, as I clearly explained in the current thread. But while SR is not used directly, you can think about part of the contribution to the GR result as being a contribution due to relative velocity between the satellite and the ground, similar to SR relative velocity effects.

"Let a lab be in free fall in an inertial frame “X”. A thrusting rocket moves freely within the lab, dragging a rope behind itself. The rope straddles the horizon of a black hole. The rocket hovers above the horizon.

"Then the rocket must be accelerating constantly. The rope is attached to the rocket. The rest frames of both are non-inertial.

He tells Zanket that a rocket in orbit around a Black Hole is a non-inertial frame.

There is no orbit here. Read zanket's statement. The rocket is hovering above the horizon. i.e. not revolving around the hole, but stationary directly above the hole.

Here he tells Prosoothus that "change in speed or direction" is non-inertial.

Out of context. In the context of flat spacetime (which is what we were talking about), what I said is completely true.

At other times James has claimed that orbit is non-inertial because it is under constant acceleration.

Only in a Newtonian context - a distinction I quite clearly explained above.

I have frequently stated that it is inertial if there is no F=ma or centrifugal/centriputal forces on it but James quickly attacks with "But you don't understand physics centrifugal force doesn't exist." But here he flip-flops and orbit is not an accelerating frame and there are no forces on it hence it is inertial.

Do you understand the point I made about curved vs. flat spacetimes? It sure sounds like you don't.

We are still waiting for Billy T or James R to post a diagram shoiwng the resolution of the twin paradox.

You never asked me for such a diagram. What exactly do you want?

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I will accept your apology for your mis-characterisation of my past posts. Your most obvious error was with regard to the "orbit" issue in the black hole discussion. Will you at least admit you were wrong there?