a) this demonstration forgot completly sail effects . Indeed imagine a coin placed such that its plane makes an angle of 45 degrees with the local flow. Then the coin will not only be pushed toward O but also in an orthoradial direction, these two forces being of equal strength. Dennis:  Uh, where on Earth did you ever get that idea?  Is that how you think sail boats work.  Forget the sails for the moment, which utilize a complicated system of pressures, is that what you think happens to coins or boats in a river current?  You think a canoe in a river will move at a 45 degrees angle to the current

At http://hometown.aol.com/djmenck/gravity.html there's an attempt at a materialistic derivation of gravity, including inverse square, perihelions, and new predictions.  The model used is Steven Rado's ideal gas sink theory. If correct, then gravitational constant, relationship of force to mass, all mathematical relationships follow from ideal gas mechanics. 1) The derivation of 1/r^2 gravitational forces First let me summarize the idea of Dennis McCarthy. He considered a radial flow of Ether converging toward a point O. He claimed that the pressure forces experienced by an _object_ of mass m at a point P in this flow gives a radial attractive force proportional to G M m /OP^2. This reproduce therefore the gravitational forces which would be created by a mass M placed in O. This presentation is naive and oversimplified but it is enough in order to understand my forthcoming criticisms. a) this demonstration forgot completely sail effects . Indeed imagine a coin placed such that its plane makes an angle of 45 degrees with the local flow. Is the 'sail effect' relevant to say a coin 1 mm thick and 1 cm diameter made of Styrofoam which is being impinged by a 1 Mev gamma fluence?  The answer of course, no, since the total attenuation coefficient (ut) is << 1.  The problem with this argument is the 'assumption' which is unwarranted.  For ANY _object_ in a directionalized momentum flux for which the interaction to same is subatomic AND very weak (i.e. the amount of the impinging fluence impeded is << 1) the argument is absolutely invalid. With the conditions you described, there is not even a radial push. So the model is completely meaningless. Really?   Given the following:  (a Styrofoam disk 1 mm thick by 1 cm diameter)                         ||                       ||                       ||                       || <====== Fee = 1 Mev/cm^2-sec @ 1Mev                       ||                       ||                       ||             dFee = Fee(1 - e^-ux) And u = (~0.08 cm/gm)(0.07 gm/cm^3) = 0.0056 cm^-1 Given t = 0.1cm, ut = 5.6E-4 Thus             DFee = Fee(0.00056) Now last I checked, photons have momentum.  Thus a deposition of said momentum into the disk will impart a pressure (force) on the disk, which will in turn, be accelerated. If particles colliding the coin are able to transfer to it some momentum, which is the fundamental premise of this model, then if the coin makes an angle of 45 degrees with the flow, it will be pushed in a direction orthogonal to the plane of the coin. Frankly your comment is quite strange. Well, while I understand that the nuances of radiation transport may be outside your area of expertise, I would think that you would comprehend the fact that, on a subatomic level, the 'number' of collisions (interactions) is only a function of the number and spacing of said entities.  Thus the old saw, same mass, same shielding.  Rotate the above disk 45 degrees, the cross-sectional area exposed to the fluence is reduced, but the effective thickness increases by the same ratio. The result, no change in the induced acceleration! Now rotate the disk 90 degrees, the resulting problem would be a good exercise for you to solve.  But, I'll give you a hint, the end result is the same. Dennis:  Your explanation, while important and valid, does not address Bourhis' argument

OK, it been awhile since I was there, and even then I did not read it thoroughly (like I've mentioned before, I don't buy any intrinsic sink theory). Dennis: Actually, you should read Rado's sink theory.  It's not intrinsic, but is naturally predicted from the formation of denser, conglomerates of material building blocks.     1) If you agree that ether particles compose the building blocks of atoms *and*.   2) if you agree that atoms are denser than ether in free vacuum.   (and almost all etherists take these two points for granted)

Moon in the middle of the radial flow which is supposed to reproduce Earth's gravitational field, this flow can not be radial anymore because it will be heavily perturbated by such a big obstacle. Therefore the toy model presented on this web page is not able to treat even the simplest possible gravitational system. Same refutation as for a... So if the particle goes through the Moon without seeing it, how can this planet be pushed toward the Earth. Again I do not see where you want to go. Maybe subtleties are not strong suit, but if we were to place a second and third disk in line with the first, they all would be accelerated at almost exactly the same rate.  The effect of one on the total fluence is extremely minor (thus the specification of weak limit). In the case of LeSagian gravity, the moon's effective attenuation coefficient is 2GM/rc^2 where M is its mass, and r its radius.  Thus we find that this is on the order of a 10^-11 reduction in the impinging fluence. First, I was not discussing LeSage model but what Dennis McCarthy presented on this web page. All his demonstration relies heavily on a purely radial flow of Ether particles. Since the moon is made of some kind of complicated Ether structure (conglomerate of vortex rings of something like that), it is absolutly obvious that the flow is not radial anymore around and through it. Dennis: 1) Almost all ether theories have the moon made of some complicated ether structure

The first of (hopefully) a few critques of Dennis'/Rado's grav. theory. Hi Dennis Okay, as I told you I am extremly busy this term, so there's noty much time to do your website justice.  However, we'll start with your derivation of the perihelion shift. First, let me make it clear that I have not yet rechecked the perhelion shift dervation in my copy of MTW (it's on my to do list) but I cannot recall it having anything to do with an inverse cube law.  That being said let's assume I'm wrong and move on to your claim. Basically as I read it, you are claiming that according to strict Newtonian mechanics, there is an inverse cube law which accounts for the perhelion shifts observed (and normally explained by GR).  You quote somebody named J. Cure to back up your claim that the inverse cube law equation derived be Newton (in the Principia, Prop. XLIV, Theorem XIV) gives rise to the perhelion shift.  Correct me if I'm wrong. Now, again I will freely admit that I have not gone through the derivation contained in the Principia, so at this point we're going to play dueling experts (then I have a more technical comment).  I wandered down to the library today and grabbed [1] Newton, I. The Principia (A New Translation) trans. I. Bernard Cohen and Anne Whitman, with an introduction and guide to the Principia by I. Bernard Cohen. [2] Chandrasekhar, S. Newton's Principia for the Common Reader Let's begin with the second ref.  As he discusses in the introduction Chandrasekhar spent about ten years (off and on) working through the Principia.  He rederived most of the importent results (basically all of book one plus some of book's two and three).  What is particularly interesting of course is that on pages 187-192 he discusses (at great length) Prop. XLIV and the associated corollaries.  Of course Chandrasekhar (argueably the greatest theoretical astrophysicist of this century) does not mention that the results of Prop. XLIV or associated theorems can be used to account for the perhelion shift of Mercury.  Even more strange is Dr. Chandrasekar makes a point of noting that the results of this section of the Principia are not covered in any modern text on classical, Newtonian mechanics.   The first ref. is, as far as I know, the standard translation of the Principia.  Although (as I said above) I did not go through Newton's derivation, I did look at the extensive guide by Dr. Cohen (one of te translators and presumably somebody who is extremely familiar with Newton's text).  Needless to say in the (more brief) discussion of Prop. XLIV contained on page 147 of the guide, Dr. Cohen makes no mention of being able to use Newton's result to derive the Perhelion shift. Those are basically arguements from authority, but essentially that's all you have in this section of your page.  Specifically your arguement is contained in the statement Cure is clearly correct in his reading of [the] Principia.  Given the choice between Cure, and my refs. as to who is correct in their readings, I'll take my refs anyday. Okay, let's move on, actually back to Chandrasekhar's text.  Essentially what he has done is rederived Newton's results, using both modern methods and Newton's orginal geometric demonstrations.  Chandrasekhar states that the central problem that Newton is addressing in this section is (in pseudo TeX notation) Given that r(phi) is the polar equation of an orbit described under the action of a centripetal force P(r) with a constant of areas h, what is the centripetal force P'(r) under which the orbit r(alphaphi) with a constant of areas (alpha)h would be described, where alpha is **some assigned constant.** ([2] page 184, emph mine). He then gives a fairly elementary derivation of the following (which is your difference of forces ) and obtains P'(r)-P(r)= h^{2}(alpha^{2}-1)/r^{3} The constant of areas here is fixed by the orbit and is variable from orbit to orbit (it's mass dependant).  The only other adjustable constant here is alpha.  But (as emphasized above) alpha is totally arbitrary.  There is really no way one could take Newton's result to indicate that alpha must be any particular value. Now af course, you might claim that the ether vortex theory fixes alpha to be a true constant, however then you'd have to explain how that comes about, since the Newtonian derivation clearly shows that alpha can be anything. Well, that's the first bit.  As I said at the beginning I'm going to check the GR derivation, but in any case I'd suggest that you take a look at my refs. and find an error in them, since they would carry far more weight (and likehood of correctness in reading) then J. Cure.