![]() |
|
|
|
Thread Tools | Display Modes |
|
#1
|
|||
|
|||
![]()
"Max Keon" wrote in message
... "George Dishman" wrote in message ... Forgive me for starting a new thread, but the old one has become fairly redundant due to the huge bulk of posts that seem to serve no purpose other than to bury the thread under a layer of wader depth bull****. much snipped as there is a major probleme here That means that any time, the acceleration adds an amount to the velocity which is equal to the product of the time and the acceleration. It doesn't add or subtract from the radius, I don't know where you got that idea. For example, if an acceleration of 2m/s^2 acts for 50s then the velocity will change by 100m/s. I'm inclined to think you actually believe that George, which is a bit disconcerting. I hadn't realised you had a problem with that. Of course it is fundamental, the word acceleration is defined as the rate of change of velocity and is unarguable and the other equations you have tried to use are all derived form this under various conditions. I'll snip the rest and concentrate on this major error, which is obviously the root of all of the confusion. What you say is true for Mercury while in its stable eccentric orbit around the Sun, so long as the anisotropy isn't included. What I said above is true for all objects changing speed for any reason whatsoever under any circumstances. Certainly _not_ under any circumstances George. Your calculations apply for any normal trajectory taken by an object naturally moving to or from a gravity source. The curved trajectory forms a natural part of the orbit shape, regardless of whether or not a complete orbit will eventually form. The only reason for it not forming is that there is other matter in the universe. But in all cases, the average radius per orbit, or potential orbit, remains unchanged. You of course agree that an object in a sustainable concentric orbit around the Sun will not shorten the radius between it and the Sun? You also agree that the radius will shorten at the full gravity rate only if its orbital speed is zero. AND ONLY THEN? The same of course applies for an eccentric orbit. Do you reject any of that so far? Centrifigal forces change at the rate of orbital speed squared, so if Mercury was traveling at an average of 24000 m/sec instead of the average 48000 m/sec, it would be restrained from falling at the full rate by 24000^2 / 48000^2 = .25 of the .0395 m/sec^2 gravity rate. The fall rate is .25 * .0395 = 9.875e-3 m/sec^2. I hope you can see that now. If you weren't aware of that then obviously nothing else I said will have made any sense to you so I can see why the conversation has been so difficult. The acceleration variations throughout Mercury's orbit cycle are not really changing anything. Mercury is not permanently shifting from its stable orbit path, and orbit velocity doesn't vary from what is an integral part of the stable orbit structure. Sorry Max, that isn't true. You said the anisotropy causes an extra acceleration, it acts to displace Mercury and since it is not directly along the path but rather points towards the Sun, it changes the direction as well as the speed. You are claiming that the anisotropy will cause Mercury's orbital speed to automatically change the moment that it's applied, which is impossible. It is what you have been telling me. "Acceleration" is the rate at which speed changes and normally is given by a = -GM / r^2 in Newtonian gravitation. You said that was changed to a = -GM / r^2 * (1 + v/c) where v is the radial component of the velocity. That is what my program models and you have seen the consequences. For example, if the pull of gravity is doubled, Mercury's orbital speed doesn't magically increase to comply with the change. Right, but it's _acceleration_ changes immediately and the speed is then the integral of that. The speed at any instant is changing by the value of the acceleration _at_that_time_. There's no point in replying to the rest of your post until this has all been cleared up. You are repeating the same old mistakes over and over again, again. The gravity force is pointing directly at the Sun, so unless Mercury falls closer to the Sun on average its orbital speed cannot be increased. Adding a new force does not change the pull direction, so orbital speed cannot change from the normal unless the average radial length changes. Can you now see that? ----- Max Keon |
#2
|
|||
|
|||
![]()
Max Keon wrote:
[...] Centrifigal forces change at the rate of orbital speed squared, so if Mercury was traveling at an average of 24000 m/sec instead of the average 48000 m/sec, it would be restrained from falling at the full rate by 24000^2 / 48000^2 = .25 of the .0395 m/sec^2 gravity rate. The fall rate is .25 * .0395 = 9.875e-3 m/sec^2. [...] The gravity force is pointing directly at the Sun, so unless Mercury falls closer to the Sun on average its orbital speed cannot be increased. Adding a new force does not change the pull direction, so orbital speed cannot change from the normal unless the average radial length changes. Can you now see that? Have you asked yourself why the centrifugal force is (m v^2 / r)? In spacetime with the Schwarzschild metric, the Euler-Lagrange equation associated with r can simply be derived as the following where the orbital motion is confined to the equatorial plane of the gravitating body. d^2r/ds^2 - (1 - 3 U) r (dO/ds)^2 = - U / r Where ** O = Longitude ** s = Spacetime ** U = G M / c^2 / r Say the orbit is circular. That mean the following. d^2r/ds^2 = 0 We have the following. (1 - 3 U) r (dO/ds)^2 = U / r Or (1 - 3 U) r^2 (dO/ds)^2 = U Or v^2 / c^2 = U / (1 - 3 U) Where (through BS but another chapter of discussion) ** v / c = r dO/ds It actually takes a little bit higher speed than Newtonian result to complete an orbit. Thus back to the Euler-Lagrange equation associated with r, we must have the centrifugal force identified as the following. m c^2 (1 - 3 U) r (dO/ds)^2 The curvature in Schwarzschild spacetime actually causes a weaker centrifugal force. In order to keep an equilibrium orbit, the speed must be a little higher than the Newtonian result. If not, it will fly spirally away. Thus, the advance of Mercury's perihelion must have two components identified as follows. ** Orbital geometric anomaly (dwelled on by physicists) ** Orbital speed anomaly (eluded physicists sigh) GR prediction based on orbital geometric anomaly alone somewhat satisfies the observation. However, including the orbital speed anomaly, it falls far short. This of course is based on the speculation that the geodesic motion follows the path of maximum accumulated spacetime. If the model of geodesics is to follow the path of least accumulated time or the principle of least time, you will find the orbital geometric anomaly describes almost the result of observation while the orbital speed anomaly is null. The net result fits the observation almost perfectly. But don't celebrate the achievement of GR yet, because under this model of geodesics it predicts photons would travel beyond the speed of light due to the Euler-Lagrange equation associated with r. Dealing with second order effects, everything must fit in place before betting on a new hypothesis. GR does not. |
#3
|
|||
|
|||
![]()
On May 29, 11:41 pm, Koobee Wublee wrote:
Max Keon wrote: [...] Centrifigal forces change at the rate of orbital speed squared, so if Mercury was traveling at an average of 24000 m/sec instead of the average 48000 m/sec, it would be restrained from falling at the full rate by 24000^2 / 48000^2 = .25 of the .0395 m/sec^2 gravity rate. The fall rate is .25 * .0395 = 9.875e-3 m/sec^2. [...] The gravity force is pointing directly at the Sun, so unless Mercury falls closer to the Sun on average its orbital speed cannot be increased. Adding a new force does not change the pull direction, so orbital speed cannot change from the normal unless the average radial length changes. Can you now see that? Have you asked yourself why the centrifugal force is (m v^2 / r)? I wonder if you have ever studied Newton's second law in a rotating coordinate system.... In spacetime with the Schwarzschild metric, the Euler-Lagrange equation associated with r can simply be derived as the following where the orbital motion is confined to the equatorial plane of the gravitating body. It isn't "spacetime", chuckles. It is an affine parameter. d^2r/ds^2 - (1 - 3 U) r (dO/ds)^2 = - U / r Where ** O = Longitude ** s = Spacetime ** U = G M / c^2 / r [snip all] Wrong. The actual radial equation of motion is: d^2r/dl^2 + GM/r^3 * (r - 2GM) * (dt/dl)^2 - GM/r(r-2GM) *(dr/dl)^2 - r(r-2GM)[(d\theta/dl)^2 + sin(\theta)^2*(d\phi/dl)^2] = 0, where l is an arbitrary affine parameter [none of this 'spacetime' bull****]. Notice this isn't anywhere even close to your idiotic equation. As usual you get even the simplest mathematics totally and completely wrong. |
#4
|
|||
|
|||
![]()
On May 30, 1:24 pm, Eric Gisse wrote:
On May 29, 11:41 pm, Koobee Wublee wrote: In spacetime with the Schwarzschild metric, the Euler-Lagrange equation associated with r can simply be derived as the following where the orbital motion is confined to the equatorial plane of the gravitating body. It isn't "spacetime", chuckles. It is an affine parameter. d^2r/ds^2 - (1 - 3 U) r (dO/ds)^2 = - U / r Where ** O = Longitude ** s = Spacetime ** U = G M / c^2 / r The actual radial equation of motion is: d^2r/dl^2 + GM/r^3 * (r - 2GM) * (dt/dl)^2 - GM/r(r-2GM) *(dr/dl)^2 - r(r-2GM)[(d\theta/dl)^2 + sin(\theta)^2*(d\phi/dl)^2] = 0, where l is an arbitrary affine parameter [none of this 'spacetime' bull****]. This is wrong. It should be corrected as follows using your symbols and notations. d^2r/dl^2 + GM/r^3 * (r - 2GM) * (dt/dl)^2 - (GM/r)/(r-2GM) *(dr/dl)^2 - (r-2GM)[(d\theta/dl)^2 + sin(\theta)^2*(d\phi/dl)^2] = 0 For simplicity without sacrificing the accuracy of the mathematical model, we can easily establish the following. ** \theta = 0 ** \phi = O ** ds = dl ** U = G M [/ c^2] / r In doing so, your equation after my correction leads to the following. dr^2/ds^2 - (1 - 2 U) r (dO/ds)^2 = - [c^2] (1 - 2 U) (dt/ds)^2 U / r + (dr/ds)^2 (U / r) / (1 - 2 U) Furthermore, we can also easily establish the following from the spacetime equation with the Schwarzschild metric. ** [c^2] (1 - 2 U) (dt/ds)^2 = 1 + (dr/ds)^2 / (1 - 2 U) + r^2 (dO/ ds)^2 Thus finally, your equation after my correction eventually leads to a much simpler and elegant equation as I have already presented. Here it is once again. d^2r/ds^2 - (1 - 3 U) r (dO/ds)^2 = - U / r Centrifugal force is not a farce. It is very real in direct contrast from denials from Dr. Roberts. Notice this isn't anywhere even close to your idiotic equation. As usual you get even the simplest mathematics totally and completely wrong. You know how to copy equations without understanding them. shrug You have no capability to copy equations correctly. sigh You are hopelessly beyond any help. get lost He knows not and not knows that he knows not is a fool. Shun Gisse and his pathetic cronies. |
#5
|
|||
|
|||
![]()
On May 30, 2:54 pm, Koobee Wublee wrote:
On May 30, 1:24 pm, Eric Gisse wrote: On May 29, 11:41 pm, Koobee Wublee wrote: In spacetime with the Schwarzschild metric, the Euler-Lagrange equation associated with r can simply be derived as the following where the orbital motion is confined to the equatorial plane of the gravitating body. It isn't "spacetime", chuckles. It is an affine parameter. d^2r/ds^2 - (1 - 3 U) r (dO/ds)^2 = - U / r Where ** O = Longitude ** s = Spacetime ** U = G M / c^2 / r The actual radial equation of motion is: d^2r/dl^2 + GM/r^3 * (r - 2GM) * (dt/dl)^2 - GM/r(r-2GM) *(dr/dl)^2 - r(r-2GM)[(d\theta/dl)^2 + sin(\theta)^2*(d\phi/dl)^2] = 0, where l is an arbitrary affine parameter [none of this 'spacetime' bull****]. This is wrong. It should be corrected as follows using your symbols and notations. No, it isn't. This is the radial equation of motion for the Schwarzschild metric. Refer to any relativity textbook, or derive the damn thing yourself. d^2r/dl^2 + GM/r^3 * (r - 2GM) * (dt/dl)^2 - (GM/r)/(r-2GM) *(dr/dl)^2 - (r-2GM)[(d\theta/dl)^2 + sin(\theta)^2*(d\phi/dl)^2] = 0 For simplicity without sacrificing the accuracy of the mathematical model, we can easily establish the following. ** \theta = 0 ** \phi = O ** ds = dl ** U = G M [/ c^2] / r I was using geometrized units - there was no c, so you have no idea if you are inserting it in the right spots. In doing so, your equation after my correction leads to the following. dr^2/ds^2 - (1 - 2 U) r (dO/ds)^2 = - [c^2] (1 - 2 U) (dt/ds)^2 U / r + (dr/ds)^2 (U / r) / (1 - 2 U) Furthermore, we can also easily establish the following from the spacetime equation with the Schwarzschild metric. The phrase "spacetime equation" is nonsense. Quit expecting people to understand your nonstandard and self-created vocabulary about a technical subject which you routinely mangle. Your inability to communicate in an understandable language says much about your understanding of general relativity. ** [c^2] (1 - 2 U) (dt/ds)^2 = 1 + (dr/ds)^2 / (1 - 2 U) + r^2 (dO/ ds)^2 Thus finally, your equation after my correction eventually leads to a much simpler and elegant equation as I have already presented. Here it is once again. d^2r/ds^2 - (1 - 3 U) r (dO/ds)^2 = - U / r Wrong, and wrong. Where did dt/ds go? Where did c go? You insisted on putting it in, why did you remove it? Where did the free floating 1 go? Where did the "3" come from? There is no way for you to pick up an extra (1 - U)r(dO/ ds)^2 term. The equations of motion /eventually/ fold into a single equation of motion with an effective potential and effective energy _after_ the application of 3 conserved quantities - none of which you have mentioned or show any amount of understanding. The rigorous derivation of said equation of motion takes about a page of math, _all_ of which you have ignored - and isn't anywhere NEAR what you have written down. Centrifugal force is not a farce. It is very real in direct contrast from denials from Dr. Roberts. Stooooopid. That's classical mechanics, which you don't even understand. Centrifugal force follows directly from the expression of Newton's 2nd law in a rotating coordinate system. Tom Roberts knows this, because he has an actual education in physics instead of whatever you pulled from a cracker jack box. Centrifugal force exists only in coordinate systems that are rotating - it is a fake force that arises from your coordinate choice. Tom Roberts also knows this, and has explained this to you and others on numerous occasions, apparently to no effect. [snip remaining whining] |
#6
|
|||
|
|||
![]()
On 30 May, 00:38, "Max Keon" wrote:
"Max Keon" wrote in message u... "George Dishman" wrote in message ... Forgive me for starting a new thread, but the old one has become fairly redundant due to the huge bulk of posts that seem to serve no purpose other than to bury the thread under a layer of wader depth bull****. I totally agree. much snipped as there is a major probleme here That means that any time, the acceleration adds an amount to the velocity which is equal to the product of the time and the acceleration. It doesn't add or subtract from the radius, I don't know where you got that idea. For example, if an acceleration of 2m/s^2 acts for 50s then the velocity will change by 100m/s. I'm inclined to think you actually believe that George, which is a bit disconcerting. I hadn't realised you had a problem with that. Of course it is fundamental, the word acceleration is defined as the rate of change of velocity and is unarguable and the other equations you have tried to use are all derived form this under various conditions. I'll snip the rest and concentrate on this major error, which is obviously the root of all of the confusion. What you say is true for Mercury while in its stable eccentric orbit around the Sun, so long as the anisotropy isn't included. What I said above is true for all objects changing speed for any reason whatsoever under any circumstances. Certainly _not_ under any circumstances George. Yes, under _any_ circumstances Max. The word "acceleration" is _defined_ as rate of change of velocity so in a short time dt the velocity will change from an initial value v_i to a final value v_f given by v_f = v_i + a * dt where a is the acceleration. v_i, v_f and a are all vectors and can be handled as x and y components as I do in the code. (You need z too in general of course but our orbits are two dimensional). Your calculations apply for any normal trajectory taken by an object naturally moving to or from a gravity source. No, it applies to _all_ motion of _any_ nature whatsoever. That is fundamental to the whole of dynamics and the process of integrating acceleration to find velocity is pure maths. .... You of course agree that an object in a sustainable concentric orbit around the Sun will not shorten the radius between it and the Sun? Obviously since concentric just means at constant radius. You also agree that the radius will shorten at the full gravity rate only if its orbital speed is zero. AND ONLY THEN? No! You are missing the whole point. Compare two similar but slightly different motions for Mercury. In the first it is in a perfectly circular orbit at some radius with an orbital speed of 48km/s: ^ | Sun M | In the second we have a snapshot of part of some more complex path when the planet is also moving at 48km/s: ^ \ Sun M \ The difference is in the direction of motion, not the speed. If the angle between the two paths is just 1 degree the Mercury will move 48000*sin(1) or 837.7m closer to the Sun in 1 second and that is without even considering additional acceleration effects. The same of course applies for an eccentric orbit. Do you reject any of that so far? It is virtually all wrong, you don't seem to know the definition of acceleration and you have completely failed to grasp the importance of the direction of motion. There's no point in replying to the rest of your post until this has all been cleared up. You are repeating the same old mistakes over and over again, again. I'm not making any mistakes Max, everything I said follows directly from the definition of velocity and acceleration. The problem is that you have forgotten about the effect of the direction of motion and discarded fundamentals to try to get the answer you want. Velocity is the integral of acceleration, _always_. The gravity force is pointing directly at the Sun, ... Yes, and Mercury is moving almost at right angles to that, so the major influence is to change the direction of motion, not the speed. so unless Mercury falls closer to the Sun on average its orbital speed cannot be increased. Adding a new force does not change the pull direction, so orbital speed cannot change from the normal unless the average radial length changes. Can you now see that? Change of orbital speed is a secondary effect due to the slow reduction of radius (Mercury moves faster than the outer planets), what you are missing is that increasing or decreasing the pull towards the Sun changes the rate at which the direction of motion alters. My code includes that effect and the results follow. George |
#7
|
|||
|
|||
![]() "George Dishman" wrote in message ps.com... On 30 May, 00:38, "Max Keon" wrote: George Dishman wrote: "Max Keon" wrote in message ... I'll snip the rest and concentrate on this major error, which is obviously the root of all of the confusion. What you say is true for Mercury while in its stable eccentric orbit around the Sun, so long as the anisotropy isn't included. What I said above is true for all objects changing speed for any reason whatsoever under any circumstances. Certainly _not_ under any circumstances George. Yes, under _any_ circumstances Max. The word "acceleration" is _defined_ as rate of change of velocity so in a short time dt the velocity will change from an initial value v_i to a final value v_f given by v_f = v_i + a * dt where a is the acceleration. v_i, v_f and a are all vectors and can be handled as x and y components as I do in the code. (You need z too in general of course but our orbits are two dimensional). Your calculations apply for any normal trajectory taken by an object naturally moving to or from a gravity source. No, it applies to _all_ motion of _any_ nature whatsoever. That is fundamental to the whole of dynamics and the process of integrating acceleration to find velocity is pure maths. You of course agree that an object in a sustainable concentric orbit around the Sun will not shorten the radius between it and the Sun? Obviously since concentric just means at constant radius. You also agree that the radius will shorten at the full gravity rate only if its orbital speed is zero. AND ONLY THEN? No! You are missing the whole point. Compare two similar but slightly different motions for Mercury. In the first it is in a perfectly circular orbit at some radius with an orbital speed of 48km/s: ^ | Sun M | In the second we have a snapshot of part of some more complex path when the planet is also moving at 48km/s: ^ \ Sun M \ The difference is in the direction of motion, not the speed. If the angle between the two paths is just 1 degree the Mercury will move 48000*sin(1) or 837.7m closer to the Sun in 1 second and that is without even considering additional acceleration effects. The same of course applies for an eccentric orbit. Do you reject any of that so far? It is virtually all wrong, you don't seem to know the definition of acceleration and you have completely failed to grasp the importance of the direction of motion. There's no point in replying to the rest of your post until this has all been cleared up. You are repeating the same old mistakes over and over again, again. I'm not making any mistakes Max, everything I said follows directly from the definition of velocity and acceleration. The problem is that you have forgotten about the effect of the direction of motion and discarded fundamentals to try to get the answer you want. Velocity is the integral of acceleration, _always_. The gravity force is pointing directly at the Sun, ... Yes, and Mercury is moving almost at right angles to that, so the major influence is to change the direction of motion, not the speed. so unless Mercury falls closer to the Sun on average its orbital speed cannot be increased. Adding a new force does not change the pull direction, so orbital speed cannot change from the normal unless the average radial length changes. Can you now see that? Change of orbital speed is a secondary effect due to the slow reduction of radius (Mercury moves faster than the outer planets), what you are missing is that increasing or decreasing the pull towards the Sun changes the rate at which the direction of motion alters. My code includes that effect and the results follow. I don't know how to get it through to George, but you are wrong and I am right. Go and study it properly. http://members.optusnet.com.au/maxkeon/peri.html It seems to me that you may have a problem understanding what is actually going on here. A gravity anisotropy is something you've never encountered before and you are trying to explain it using reasoning that you are accustomed to. That doesn't work. Perhaps it might help if you realize that you are in no better a position to see the truth than anyone else who has evolved through any other society where "truth" has been indoctrinated into them over many years. I use the word "indoctrinated" because that's exactly what it is in every form of learning. One cannot progress if they don't, at least temporarily, blindly accept certain elements of the learning program. But if you do know that what I say is correct, that's a whole new ball game. I'm going to need to elaborate quite a bit, so don't nod off. I just happened to catch the final episode of a series, titled "The Root Of All Evil", within the parent program "Compass" which is aired on the ABC (Australia). Richard Dawkins of Oxford University (you perhaps know him) highlighted the consequences of the religious indoctrination of the young. He described it as a virus of faith which is transmitted from the older generation to the new. It's a never ending cycle that divides a community and leads to a religious intolerance that extends to everyone who is not likewise indoctrinated. He also mentioned that even though science is constantly falsifying the basis for creationism, the message doesn't seem to be getting through. The problem is, no matter what evidence science may find, it could have been created as an integral part of the universe while the universe was being made in the designated time of 6 or 7 days, depending what one wants to believe. So, it really doesn't matter a damn what evidence is found. I don't want to seem overly critical but offering the big bang theory as an alternative reality is absolutely useless. It does not describe how the universe began, or how it will end. All it does is attempt to explain why the universe is what it is. How can that constitute reality to anyone? The door is wide open. It's about time the zero origin universe assumed the role of explaining reality, that's what I think. That universe naturally has a beginning which can be seen when we look back in time. We see how the universe has evolved up until now, but we can't see into the future to the ultimate end of the universe. If you understood the consequences of that origin and where we are heading, you would probably realize that life is not about the individual or the fulfillment of one's self indulgent desires, including working toward claiming the pot of eternal bliss at the end of life's rainbow. All life, even in a primitive state of evolution, is unbounded in its potential for future development. Every bit of life in this universe has infinitely more chance of averting the ultimate fate of everything that exists in this universe than no life at all. I watch my cat loafing around with no apparent purpose in life. What is he waiting for? What is the point to the life of a tiny amoeba floating about at the edge of a backwater? What is the point to my life, or your life? Life may not seem to offer much hope in the grand scheme of the universe, BUT WITHOUT IT, THERE IS NO HOPE AT ALL. No matter how mundane a life may appear to be, it still can be of absolute importance. Who knows what the future consequences of its existence will be? But there is a catch22. The demand for the planet's dwindling resources in the rapidly developing countries is rising exponentially. And that doesn't really take into account the enormous future impact that 220000 plus per day world population growth. Even a blind man could see that it MUST eventually come to a sticky end. Choosing to ignore that obvious fact and blundering down the same old path will lead to the self extinction of mankind and just about everything else on the planet. So why did we even bother in the first place. It would have been far better for us to stay in the backwater with the amoebas and let something else have a go. Even though Richard Dawkins would probably tell me I have no right to impose my own personal morality on anyone, any more than does anyone have the right to impose their own personal morality on me, which is invariably not just a moral issue but always extends to the imposition of one's entire "reality", one thing is for certain, if we can't all learn to live together as one united community, there is not one hope in hell of us ever getting out of the mess that we have so stupidly created here on Earth. I don't know what the fix will be, but I do know that I won't like it any more than will anybody else. But failure here is not an option. Do you now understand the importance of knowing the truth? ----- Max Keon You know the question, just as I did. What is the Matrix? Power, control, |
#8
|
|||
|
|||
![]() "Max Keon" wrote in message u... "George Dishman" wrote in message ps.com... On 30 May, 00:38, "Max Keon" wrote: George Dishman wrote: "Max Keon" wrote in message ... I'll put back part you snipped as it is the core of the disagreement: For example, if an acceleration of 2m/s^2 acts for 50s then the velocity will change by 100m/s. .... What I said above is true for all objects changing speed for any reason whatsoever under any circumstances. Certainly _not_ under any circumstances George. Yes, under _any_ circumstances Max. The word "acceleration" is _defined_ as rate of change of velocity so in a short time dt the velocity will change from an initial value v_i to a final value v_f given by v_f = v_i + a * dt where a is the acceleration. v_i, v_f and a are all vectors and can be handled as x and y components as I do in the code. (You need z too in general of course but our orbits are two dimensional). .... .. it applies to _all_ motion of _any_ nature whatsoever. That is fundamental to the whole of dynamics and the process of integrating acceleration to find velocity is pure maths. snip application of above until we get this agreed. I don't know how to get it through to George, but you are wrong and I am right. Go and study it properly. These may help you: http://www.staff.amu.edu.pl/~romango...eleration.html http://hep.physics.indiana.edu/~rick...inematics.html http://www.blurtit.com/q286865.html You could also look at the "Force and Motion" topic he http://learningcenter.nsta.org/produ...e_objects.aspx It concentrates mainly on position and velocity and is a bit light on acceleration but it is well presented and has lots of questions to let you check your progress. Once you have gone through that, look again at what I said at the top: For example, if an acceleration of 2m/s^2 acts for 50s then the velocity will change by 100m/s. Do you still deny that? It seems to me that you may have a problem understanding what is actually going on here. A gravity anisotropy is something you've never encountered before and you are trying to explain it using reasoning that you are accustomed to. That doesn't work. I have encountered anisotropy in many areas but actually that doesn't matter, you have done the work on that side and all I need is your result. You have told me that the effect is to change the acceleration due to gravity from Newton's equation: a = -GM / r^2 to a = -GM / r^2 * (1 + v/c) where v is the radial speed, the rate of change of the radius, and the direction is the same as Newton's. You have specified the acceleration Max, all that is left is to integrate it once to get velocity and a second time to get position and the results fall out of that calculation. I don't need to know anything more about your ideas at all. Now if that equation doesn't represent your idea then obviously my comments will similarly be misplaced but that is what you have provided so I am taking it at face value. snip diatribe Do you now understand the importance of knowing the truth? Of course, so go and look up the definition of "acceleration" and you will find I have been telling you the truth throughout. Your analysis is wrong for numerous reasons that I listed before and which you have ignored. I have only made one significant error during the course of the discussion which was when I did a very quick simulation of your equation and accidentally got the sign wrong, I used (1 - v/c) instead of (1 + v/c) so the eccentricity increased instead of decreasing but that was some time ago and the Basic code has the correct sign for your theory. It is available for anyone to peer review [1] and I'll repeat the part relevant to the physics here since we have changed thread since it was posted: r2 = x * x + y * y radius = SQR(r2) vr = (radius - lastradius) / dt lastradius = radius Newton = GM / r2 ' The constant GM is negative anisotropy = Newton * (vr / c) acceleration = Newton + anisotropy ax = acceleration * (x / radius) ay = acceleration * (y / radius) vx = vx + dt * ax vy = vy + dt * ay x = x + dt * (vx + 0.5 * dt * ax) y = y + dt * (vy + 0.5 * dt * ay) time = time + dt George [1] If anyone actually peer reviews that code, be aware that in the actual version I run, the acceleration for the next time step uses a linear prediction from the current and previous acceleration values to get: forward_mean = (3 * current - previous) / 2 |
#9
|
|||
|
|||
![]() "George Dishman" wrote in message ... "Max Keon" wrote in message u... I'll put back part you snipped as it is the core of the disagreement: I'll snip that and reply where it reappears. --- I don't know how to get it through to George, but you are wrong and I am right. Go and study it properly. These may help you: http://www.staff.amu.edu.pl/~romango...eleration.html http://hep.physics.indiana.edu/~rick...inematics.html http://www.blurtit.com/q286865.html You could also look at the "Force and Motion" topic he http://learningcenter.nsta.org/produ...e_objects.aspx It concentrates mainly on position and velocity and is a bit light on acceleration but it is well presented and has lots of questions to let you check your progress. Once you have gone through that, look again at what I said at the top: For example, if an acceleration of 2m/s^2 acts for 50s then the velocity will change by 100m/s. Do you still deny that? I don't think I ever denied it in the sense that you've written it. But I certainly disagree that velocity will change as you propose if the force is that of gravity acting on an object which is in a stable orbit. Radial velocity will vary according to the degree of eccentricity, but the average orbit radius is not going to change at all. Neither is average orbital speed. If the gravity force was to double, accelerating the object at 4 m/sec^2, the average orbit radius is not going to shrink by the added rate of 2 m/sec^2, but would fall inward at a much lesser rate. 127645 m/sec orbital speed had previously counteracted the 2 m/sec^2 fall pointing directly at the Sun while the object was held in a stable orbit at a radius of 8146563693 meters, but now the required orbital speed to hold it in a stable orbit at that radius around the double Sun mass is 180517 m/sec. It should be obvious that if the object falls directly inward at 4 m/sec^2 when its orbital speed is zero and zero distance when its orbital speed is 180517 m/sec, the direct fall rate is going to reduce proportionally as orbital speed increases. So what is the true direct fall rate of the object now that it's traveling to slowly to counteract the direct fall? That rate is obviously not linear, in the realm of gravity. http://members.optusnet.com.au/maxkeon/falrate.jpg demonstrates what that rate would be. From the graph: l ----------va------------------- l l l -----vb------------- l l----------l------------------------l l --vc-- l vc^2 / va^2 * gravity = fall rate vc = va - vb 180517 - 127645 = 52872 52872^2 / 180517^2 * 4 = .343 m/sec^2 inward fall rate. It seems to me that you may have a problem understanding what is actually going on here. A gravity anisotropy is something you've never encountered before and you are trying to explain it using reasoning that you are accustomed to. That doesn't work. I have encountered anisotropy in many areas but actually that doesn't matter, you have done the work on that side and all I need is your result. You have told me that the effect is to change the acceleration due to gravity from Newton's equation: a = -GM / r^2 to a = -GM / r^2 * (1 + v/c) where v is the radial speed, the rate of change of the radius, and the direction is the same as Newton's. You have specified the acceleration Max, all that is left is to integrate it once to get velocity and a second time to get position and the results fall out of that calculation. I don't need to know anything more about your ideas at all. Now if that equation doesn't represent your idea then obviously my comments will similarly be misplaced but that is what you have provided so I am taking it at face value. snip diatribe Let's hope my message has been noted and understood, however it was presented. Do you now understand the importance of knowing the truth? Of course, so go and look up the definition of "acceleration" and you will find I have been telling you the truth throughout. Your analysis is wrong for numerous reasons that I listed before and which you have ignored. I have only made one significant error during the course of the discussion which was when I did a very quick simulation of your equation and accidentally got the sign wrong, I used (1 - v/c) instead of (1 + v/c) so the eccentricity increased instead of decreasing but that was some time ago and the Basic code has the correct sign for your theory. It is available for anyone to peer review [1] and I'll repeat the part relevant to the physics here since we have changed thread since it was posted: I've added to your program extract so that it can be run and tested. The resident text explains what I've done. Take note while it's running, that Mercury falls closer to the Sun on both the up and the down leg of the orbit. Regardless of what the math says, that is wrong. A fundamental consequence of the anisotropy is that it will be drawn more to the Sun on the way up and less on the way down. The trajectory on the down leg should move toward being further from the Sun than normal, and that doesn't happen. The other thing that you still don't seem to grasp is the _fact_ that the whole process is entirely elastic. I've demonstrated why many times. Should I do it again? ----- Max Keon ------------------ 'In the duplicated program following "ac:", the anisotropy is excluded. 'The program is now set up to test your updated method against your 'previous method. I know you can do it yourself because you wrote the 'program, but I've included some examples to make it easier for anyone 'else who wants to run it. 'The purple curve only, includes the anisotropy. 'Control-break halts the program. It's the only way out. Any other 'method just bogs the program down. F4 brings back the result. DEFDBL A-Z SCREEN 12 CLS LOCATE 16, 66: PRINT "Aphelion" c = 300000000# GM = -1.327D+20 x = 70000000000# multi = .000000005# ' Multiplier for the graphics. mx = x ' Aligns program 2 with program 1. ' Program 2 has no anisotropy. '--------------------------------- vy = 39000#: dt = 1000# ' vy = 39000#: dt = 100# ' vy = 8000#: dt = 50# ' vy = 8000#: dt = 10# ' The current program setup is for Mercury according to your latest ' program update. dt is 1000 second chunks. Swap the switch to run line ' 2 of the set and note the difference. Mercury now falls at a different ' rate. dt must therefore be set to 1 for it to run properly. But even ' then, Mercury is falling almost as fast without an anisotropy. I don't ' think that was intended. Why did you change the program anyway? It ' better represented your view before. Am I doing something wrong? ' I am very impressed with what your program does though. '--------------------------------- mvy = vy ' Aligns program 2 with program 1. aa: ' END ' Remove this switch to end the program. r2 = x * x + y * y radius = SQR(r2) vr = (radius - lastradius) / dt lastradius = radius Newton = GM / r2 ' The constant GM is negative anisotropy = Newton * (vr / c) acceleration = Newton + anisotropy ax = acceleration * (x / radius) ay = acceleration * (y / radius) vx = vx + dt * ax vy = vy + dt * ay '------------------------------------- x = x + dt * (vx + .5 * dt * ax) ' Updated method. y = y + dt * (vy + .5 * dt * ay) ' x = x + dt * vx ' Previous method. ' y = y + dt * vy ' Swap the switches in both programs. '------------------------------------- time = time + dt IF time 1000 THEN GOSUB ab GOSUB ac GOTO aa ab: time = 0 CIRCLE (200 + x * multi, 250 + y * multi), 0, 13 CIRCLE (200 + mx * multi, 250 + my * multi), 0, 11 RETURN ac: mr2 = mx * mx + my * my mradius = SQR(mr2) mvr = (mradius - mlastradius) / dt mlastradius = mradius mNewton = GM / mr2 ' The constant GM is negative ' manisotropy = mNewton * (mvr / c) macceleration = mNewton ' + manisotropy max = macceleration * (mx / mradius) may = macceleration * (my / mradius) mvx = mvx + dt * max mvy = mvy + dt * may '---------------------------------------- mx = mx + dt * (mvx + .5 * dt * max) ' Updated method. my = my + dt * (mvy + .5 * dt * may) ' mx = mx + dt * mvx ' Previous method. ' my = my + dt * mvy ' Swap the switches. '---------------------------------------- RETURN |
#10
|
|||
|
|||
![]() "Max Keon" wrote in message u... "George Dishman" wrote in message ... "Max Keon" wrote in message u... I'll put back part you snipped as it is the core of the disagreement: I'll snip that and reply where it reappears. --- I don't know how to get it through to George, but you are wrong and I am right. Go and study it properly. These may help you: http://www.staff.amu.edu.pl/~romango...eleration.html http://hep.physics.indiana.edu/~rick...inematics.html http://www.blurtit.com/q286865.html You could also look at the "Force and Motion" topic he http://learningcenter.nsta.org/produ...e_objects.aspx It concentrates mainly on position and velocity and is a bit light on acceleration but it is well presented and has lots of questions to let you check your progress. Once you have gone through that, look again at what I said at the top: For example, if an acceleration of 2m/s^2 acts for 50s then the velocity will change by 100m/s. Do you still deny that? I don't think I ever denied it in the sense that you've written it. Here is the quote, it sounds as though you objected: [GD:] For example, if an acceleration of 2m/s^2 acts for 50s then the velocity will change by 100m/s. [MK:] I'm inclined to think you actually believe that George, which is a bit disconcerting. Anyway, you seem to say the same again: But I certainly disagree that velocity will change as you propose if the force is that of gravity acting on an object which is in a stable orbit. Acceleration is defined as being the rate at which the velocity is changing. No matter what the circumstances, that means that the velocity is found by integrating the acceleration. If a constant acceleration of 2m/s^2, or "2m/s per second" applies for 50 seconds then the change of speed will be 50 * 2 or 100 m/s. The fact that it is gravity that produces the acceleration is not important, if the velocity didn't change by 100 m/s in the 50s then the value of the acceleration would be something else, it would be dv/50 where dv is the change in velocity. Of course the acceleration isn't constant and in a stable orbit, integrating the acceleration over a whole orbit must get the speed back to its original value - that's what stable means. The point here though is that you have changed the formula for the acceleration by adding the anisotropy and we must integrate that to find out whether the orbit is stable or not. Radial velocity will vary according to the degree of eccentricity, but the average orbit radius is not going to change at all. Neither is average orbital speed. You don't know that until you do the calculation and that's what the program is about. However, your own description below matches mine so I'm not sure why you are saying this. If the gravity force was to double, accelerating the object at 4 m/sec^2, the average orbit radius is not going to shrink by the added rate of 2 m/sec^2, but would fall inward at a much lesser rate. If the force doubled for just 1 second at the middle of the inward leg and then went back to normal, it would cause a slight change in the direction of the motion towards the sun but the change of energy would be negligible. That would decrease the perihelion and since the planet is back in a stable elliptical orbit with the same energy, it would also increase the aphelion half an orbit later, hence it would change the eccentricity. In fact you said the anisotropy _decreases_ the force on the inward leg so that increases the perihelion distance and decreases the aphelion reducing the eccentricity. Suppose the planet would move from A to B to C to D without the anisotropy, it goes from A to B to E to F if the anisotropy is switched on between B and E then off again: A B E C F D Sun The same happens on the outward leg, the slight _increase_ in gravity as the planet is moving away pulls it round to point more towards the Sun again reducing the aphelion. Sun A B E C F D Because that happens on every orbit, the eccentricity falls on both the outward and inward legs of every orbit and it ends up circular, which is the only stable two-body configuration when your anisotropy is included. snip diatribe Let's hope my message has been noted and understood, however it was presented. We are both aiming to understand accurately what your modification to the formula predicts so: Do you now understand the importance of knowing the truth? was unnecessary. Of course, so go and look up the definition of "acceleration" and you will find I have been telling you the truth throughout. Your analysis is wrong for numerous reasons that I listed before and which you have ignored. I have only made one significant error during the course of the discussion which was when I did a very quick simulation of your equation and accidentally got the sign wrong, I used (1 - v/c) instead of (1 + v/c) so the eccentricity increased instead of decreasing but that was some time ago and the Basic code has the correct sign for your theory. It is available for anyone to peer review [1] and I'll repeat the part relevant to the physics here since we have changed thread since it was posted: I've added to your program extract so that it can be run and tested. The resident text explains what I've done. Take note while it's running, that Mercury falls closer to the Sun on both the up and the down leg of the orbit. Regardless of what the math says, that is wrong. I agree, that would be wrong, but it is farther away when I run my original program. I'll recheck and maybe post some numbers later in case you changed something by mistake when editing but I have other pressing (boring) stuff to do first. A fundamental consequence of the anisotropy is that it will be drawn more to the Sun on the way up and less on the way down. The trajectory on the down leg should move toward being further from the Sun than normal, and that doesn't happen. You are absolutely correct, that is what I said above, and when I run my program that is what happens. I'll run your version later and see if I can find why you think it is the opposite. Can you not see that moving the planet away from the Sun on the inward leg increases perihelion while drawing it toward the Sun on the up leg decreases aphelion so both reduce the eccentricity as I have been saying? The other thing that you still don't seem to grasp is the _fact_ that the whole process is entirely elastic. I've demonstrated why many times. Should I do it again? Max, you have never demonstrated that at all and you cannot do so. The requirement for it to be elastic is that the force must be a function of radial distance _only_. Since you include speed in the formula, it isn't elastic. Let me just pull out one other point: ' ... Why did you change the program anyway? It ' better represented your view before. Am I doing something wrong? I assume you mean this bit: vx = vx + dt * ax vy = vy + dt * ay '------------------------------------- x = x + dt * (vx + .5 * dt * ax) ' Updated method. y = y + dt * (vy + .5 * dt * ay) ' x = x + dt * vx ' Previous method. ' y = y + dt * vy ' Swap the switches in both programs. '------------------------------------- The equations apply to a single small time step lasting dt seconds. Take some simple numbers for the x values as an example, suppose the step is dt = 3 seconds, the speed at the start is vx = 100 m/s and the acceleration is ax = 6 m/s^2. vx = vx + dt * ax says that speed at the end of the step will have risen from 100 m/s to 118 m/s. The simpler equation x = x + dt * vx says the location has changed by 3 * 100 = 300 m during that time, but the speed isn't a constant 100m/s, it changed from 100 m/s to 118 m/s. The _average_ speed during the period is 109 m/s so the accurate calculation of distance moved is 3 * 109 = 327 m. The formula x = x + dt * (vx + .5 * dt * ax) gives a shift of dt * (vx + .5 * dt * ax) = 3 * (100 + 0.5 * 3 * 6) = 3 * (100 + 9) = 327 m which is correct. The change just improves the accuracy. In the program I'm running at the moment, I have another small change that does the same sort of thing to account for the slight change of the acceleration during the time step. The aim of all this is that better accuracy of the basic equations means we can use a larger step duration so get the program to run faster. George |
|
Thread Tools | |
Display Modes | |
|
|
![]() |
||||
Thread | Thread Starter | Forum | Replies | Last Post |
Anisotropy in the gravity force, and Mercury. | Max Keon | Astronomy Misc | 247 | June 4th 07 04:46 PM |
Anisotropy and Mercury (2) | Max Keon | Astronomy Misc | 0 | May 30th 07 12:33 AM |
Anisotropy in the gravity force, and Mercury. | Randy Poe | Astronomy Misc | 3 | May 24th 07 02:43 AM |
Anisotropy in the gravity force, and Mercury. | Randy Poe | Astronomy Misc | 0 | May 23rd 07 02:33 PM |
Anisotropy in the gravity force, and Mercury. | Randy Poe | Astronomy Misc | 0 | May 23rd 07 02:32 PM |