[SOLVED] Why is push gravity concept considered not viable by mainstream science? Hello guys, I would like to know the main reasons why the push gravity concept is not considered as a viable concept by mainstream science. I know it gave rise to numerous published works, amongst which we have those of Lorentz, H.Poincare, F.Brush, Secchi, Leray, V.Thomson, Schramm, Tait, Isenkrahe, Preston, Jarolimek, Waachy, Rynsanek, Darwin, Majorana... so it cannot be all wrong. Please note, I am NOT asking about Le Sage ultramundane particles theory (which also falls under the push gravity category), which I can easiely discredit myself. I'm mostly interested in the concept of electromagnetic radiation pressure of high frequency radiation acting as the gravitational mechanism, and its shadowing creating the inverse square law, low pressure areas. Thanks, S.Borg.
Re: Why is push gravity concept considered not viable by mainstreamscience? Blaze Labs wrote: > > Hello guys, > > I would like to know the main reasons why the push gravity concept is > not considered as a viable concept by mainstream science. I know it > gave rise to numerous published works, amongst which we have those of > Lorentz, H.Poincare, F.Brush, Secchi, Leray, V.Thomson, Schramm, Tait, > Isenkrahe, Preston, Jarolimek, Waachy, Rynsanek, Darwin, Majorana... so > it cannot be all wrong. > > Please note, I am NOT asking about Le Sage ultramundane particles > theory (which also falls under the push gravity category), which I can > easiely discredit myself. I'm mostly interested in the concept of > electromagnetic radiation pressure of high frequency radiation acting > as the gravitational mechanism, and its shadowing creating the inverse > square law, low pressure areas. Electromagnetism propagates as spin-1 vector bosons. If gravitation is quantized it propagates as spin-2 tensor bosons. The selection rules for allowed transitions are different. EM and gravitation do not unify - not even if you are wearing Kaluza-Klein jeans. EM is trivially shielded with alternating layers of grounded conductor (Faraday cage) and lossy inductor (e.g., ferrite) and eventually by electron scattering (nuclear shielding for beta-rays). Gravitation cannot be shielded. The source of monopole radiation is a changing monopole moment for a charge q or for a mass m. Since charge and mass are conserved, there can be neither monopole electromagnetic radiation nor monopole gravitational radiation. The source of dipole radiation is a changing dipole moment. (Punctiliously, you need a second time derivative of the dipole moment.) For a pair of charges d = qr + q'r' and there's nothing special about the derivatives. For a pair of masses, the gravitational dipole moment is d = mr + m'r' and its time derivative is mv + m'v' = p + p' By conservation of momentum the second time derivative of the gravitational dipole moment is zero, and you can go to a center of momentum frame and set the first derivative to zero as well. There is no gravitational "electric dipole" radiation. Consider the analog of "magnetic dipole" radiation. The gravitational equivalent of the magnetic dipole moment for a pair of charges is M = mv x r + m'v' x r' ("x" is the cross product, "mv" is the "mass current") But M is the total angular momentum, which is also conserved. There is no gravitational "magnetic dipole" radiation. The next moment up is quadrupole, with no relevant conservation laws, so gravitational quadrupole radiation is permitted. -- Uncle Al http://www.mazepath.com/uncleal/ (Toxic URL! Unsafe for children and most mammals) http://www.mazepath.com/uncleal/qz3.pdf
Re: Why is push gravity concept considered not viable by mainstream On Wed, 24 May 2006, Blaze Labs wrote: > I would like to know the main reasons why the push gravity concept is > not considered as a viable concept by mainstream science. I know it > gave rise to numerous published works, amongst which we have those of > Lorentz, H.Poincare, F.Brush, Secchi, Leray, V.Thomson, Schramm, Tait, > Isenkrahe, Preston, Jarolimek, Waachy, Rynsanek, Darwin, Majorana... so > it cannot be all wrong. > > Please note, I am NOT asking about Le Sage ultramundane particles > theory (which also falls under the push gravity category), which I can > easiely discredit myself. I'm mostly interested in the concept of > electromagnetic radiation pressure of high frequency radiation acting > as the gravitational mechanism, and its shadowing creating the inverse > square law, low pressure areas. Isn't this exactly what Brush wrote about? A search to see who cite Brush's paper might be revealing. Perhaps it's just the observation that, apart from rather speculative push-gravity effects, we don't seem to be immersed in a bath of lots and lots of ultra-gamma rays? Modern experiments on the falling of single cold atoms might be a conclusive disproof, since radiation pressure due to ultra-high frequency radiation tends to be in discrete jumps; E=hf and all that. This isn't observed. I see you list Majorana, although perhaps his suggestion should be called "anti-push" (surely better than "suck"!) gravity. My impression is that while push gravity, at least in certain limits, give plausible results, doesn't offer any improvement over other theories of gravitation, while introducing severe difficulties related to the exchange of energy between the gravitational particle flux and conventional matter. A relativistic treatment of gravitational particles (relevant if photons) doesn't seem to improve matters such as galactic rotations curves (thanks Rob for this). -- Timo Nieminen - Home page: http://www.physics.uq.edu.au/people/nieminen/ E-prints: http://eprint.uq.edu.au/view/person/Nieminen,_Timo_A..html Shrine to Spirits: http://www.users.bigpond.com/timo_nieminen/spirits.html
Re: Why is push gravity concept considered not viable by mainstreamscience? Blaze Labs <saviour@blazelabs.com> wrote: > Hello guys, > I would like to know the main reasons why the push gravity concept is > not considered as a viable concept by mainstream science. There are a few generic objections, along with particular problems with particular models. The main generic objections I know of are 1. Drag: As Feynman pointed out in the Feynman Lectures, anything that's capable of "pushing" will also create drag on a moving object. There are very strong observational limits on such drag, in the Solar System and in binary pulsar systems. 2. Aberration: Suppose "pushing" particles move at a speed v, and look at the effect on the Solar System. For a planet at distance d from the Sun, the "push" will not be toward the instantaneous position of the Sun, but towards its position at a time d/v in the past. This is a drastic effect -- if v is the speed of light, the Solar System would be drastically unstable over a thousand-year time scale. (The effect of aberration is to increase the velocity of a planet, and you might hope that drag would cancel it. But it's easy to check that such cancellation can occur at, at most, one radial distance from the Sun.) 3. Principle of equivalence: It is observed that gravity acts not only on mass, but on all forms of energy. A "push gravity" theory would have to come with an explanation of how the particles that do the pushing manage to push against, for example, electrostatic binding energy and the kinetic energy of electrons in an atom, and why that "push" exactly matches the "push" against ordinary matter. In particular, we observe that gravitational binding energy itself gravitates. This seems to require self-interaction among the pushing particles. On the other hand, the accuracy of the inverse square law over long distances requires that the self-interaction be very small -- you certainly need a mean free path larger than the size of the Solar System if you don't want to mess up Pluto's orbit. 4. Gravitational screening: There are very strong limits on the kind of "gravitational screening" one would expect from a "push gravity" model -- see, for example, Unnikrishnan et al., Phys. Rev. D 63 (2001) 062002. [...] > Please note, I am NOT asking about Le Sage ultramundane particles > theory (which also falls under the push gravity category), which I can > easiely discredit myself. I'm mostly interested in the concept of > electromagnetic radiation pressure of high frequency radiation acting > as the gravitational mechanism, and its shadowing creating the inverse > square law, low pressure areas. You immediately run into trouble with the principle of equivalence, for one thing. Electromagnetic waves don't interact with other electromagnetic waves (except by truly tiny quantum effects); but gravity bends light. Nor do electromagnetic waves interact with internal energy, not with neutrinos; but these *are* affected by gravity. You also run into grave problems with aberration (see above), and very probably with drag. You would *further* have to explain why this high frequency radiation is not absorbed by the Earth enough to lead to gravitational screening of the type ruled out by experiment. Note that "high frequency [electromagnetic] radiation" is gamma radiation. There are experimental measurements of very high energy gamma rays, and a fair amount is known about their spectrum. I suspect you would have a very hard time reconciling your model with these observations. Steve Carlip
Re: Why is push gravity concept considered not viable by mainstreamscience? carlip-nospam@physics.ucdavis.edu wrote: snip > > Electromagnetic waves don't interact with other > electromagnetic waves (except by truly tiny quantum effects); snip > Steve Carlip > Steve Could you please provide a reference to: "truly tiny quantum effects" of "interacting Electromagnetic waves" Richard
Re: Why is push gravity concept considered not viable by mainstream Timo A. Nieminen wrote: > ... Perhaps it's just the observation that, > apart from rather speculative push-gravity effects, we don't seem to be > immersed in a bath of lots and lots of ultra-gamma rays? OTOH, de Broglie showed that treating a particle as a standing wave would predict many effects which were subsequently found to be just so. If a particle is a standing wave, then (as Wheeler and Feynman got close to saying) it is a combination of both an in and out wave at the Compton frequency of the particle. This is indeed ultra-gamma rays, but it is not something that "happens to the particle" but rather "what the particle is". I highly recommend the web site of Gabriel LaFreniere at http://www.glafreniere.com/matter.htm which has many animated GIFs showing how standing waves look and produce all the effects of de Broglie, including waves relating to particles in motion and much more. > My impression is that while push gravity, at least in certain limits, give > plausible results, doesn't offer any improvement over other theories of > gravitation, while introducing severe difficulties related to the exchange > of energy between the gravitational particle flux and conventional matter. If the particle as a standing wave idea is adopted, then LeSage gravity does follow still. carlip-nospam@physics.ucdavis.edu wrote: > 1. Drag: As Feynman pointed out in the Feynman Lectures, anything > that's capable of "pushing" will also create drag on a moving object. > There are very strong observational limits on such drag, in the > Solar System and in binary pulsar systems. > 2. Aberration: Suppose "pushing" particles move at a speed v, and > look at the effect on the Solar System. For a planet at distance d > from the Sun, the "push" will not be toward the instantaneous > position of the Sun, but towards its position at a time d/v in the > past. This is a drastic effect -- if v is the speed of light, the > Solar System would be drastically unstable over a thousand-year > time scale. When the in and out waves are considered, it seems to me that both the drag and aberration problems are solved. That is because there is an almost exactly equal and opposite effect from each of the two parts of the wave. I say almost equal and opposite because there does have to be a difference of 1 part in 10^40 between the two fluxes in order to explain why gravity is that must weaker than other forces. That difference also leads to a correct prediction of the cosmological redshift as being a side effect of the imbalance. These relationships are deeply satisfying. > 3. Principle of equivalence: It is observed that gravity acts not > only on mass, but on all forms of energy. A "push gravity" theory > would have to come with an explanation of how the particles that do > the pushing manage to push against, for example, electrostatic binding > energy and the kinetic energy of electrons in an atom, and why that > "push" exactly matches the "push" against ordinary matter. If particles are a type of e/m standing wave then this would of course be so. > 4. Gravitational screening: There are very strong limits on the kind > of "gravitational screening" one would expect from a "push gravity" > model -- see, for example, Unnikrishnan et al., Phys. Rev. D 63 (2001) > 062002. There are of course observations of effects of shadows from eclipses on pendulums (Maurice Allais) and on gravitational acceleration (Wang and Wang(?)) which do show that there is screening, although it might better be described as a mixture of screening and scattering. Ray Tomes http://ray.tomes.biz/ http://www.cyclesresearchinstitute.org/
<carlip-nospam@physics.ucdavis.edu> wrote in message news:e54rdf$qcb$1@skeeter.ucdavis.edu... > Blaze Labs <saviour@blazelabs.com> wrote: >> Hello guys, > >> I would like to know the main reasons why the push gravity concept is >> not considered as a viable concept by mainstream science. > > There are a few generic objections, along with particular problems with > particular models. The main generic objections I know of are > > 1. Drag: As Feynman pointed out in the Feynman Lectures, anything > that's capable of "pushing" will also create drag on a moving object. > There are very strong observational limits on such drag, in the > Solar System and in binary pulsar systems. I assume (perhaps incorrectly) that you are referring to the paragraph in Vol. I, pages 7-9 to 7-10, in which Feynman commented on the theory of a mechanism of gravitation. I was thinking that if these "push-particles" are traveling at the speed of light, c, something like the following might hold. Let F be the flux of these particles thoughout space (i.e., the number of particles passing through unit area in unit time.) Also, assume the flux is isotropic in direction. Consider a thin sheet of matter traveling at speed u in the +X direction (traveling broadside so you see the full area when looking along X.) To simplify, consider only those particles going either in the +X or -X direction. (Nothing is lost, in principle, by doing this, as you could integrate over velocity components for other directions.) When the object is at rest, it sees the same particle flux, F,coming from both the front side and the hind side. But in motion, the flux it meets is increased to F(c+u)/c and the flux from behind is decreased to F(c-u)/c. If Feynman's anology with running in the rain applies, the thing would certainly absorb more particles from the front than from the back per unit time, and would feel a resistance to the motion. (With raindrops, if they hit, they are absorbed.) However, the sheet of matter is composed of individual absorber particles, say "atoms". Looking at a single atom, the number of encounters per second it has with a push-particle is proportional to the particle flux in the vicinity of the atom. The number absorbed per second by that atom is equal to the number of encounters per second times the probability, p, of absorption per encounter.So, for push-particles coming from the front, an atom in the sheet of material would absorb N(1) = ApF(c+u)/c particles per second (1) where A is the proportionality constant mentioned above for encounters, and p is the probability of absorption per encounter. This same atom would absorb from behind, N(2) = ApF(c-u)/c particles per second. (2) If the probability were the same in each case, the atom would certainly absorb more per second from the front than from behind. However, the atom (or whatever absorbing "particle") may be assumed to have an effective absorbing diameter,d. A particle can be absorbed by it only when it is traversing this distance through, or close by, the atom. It takes a time t(1) = d/(c+u) for the particles meeting the atom to traverse its sphere of influence. And for those coming from the rear, it takes a time t(2) = d/(c-u) for them to get away from its influence. The probability of absorption per encounter should also be proportional to the time lapse of the encounter. (if it stays in the vicinity of the atom longer, it should have a higher probability of absorption.) Therefore, the probability of absorption in each case would be p(1) = Bd/(c+u) for particles meeting it, and p(2) = Bd/(c-u) for particles coming from behind, where B is the proportionality constant. Replacing the probability p in equations (1) and (2) above with these probabilities as a function of the time lapse of encounter, gives: the number absorbed from the front per second by a given atom as N(1) = A[Bd/(c+u)]F[(c+u)/c] = (ABdF)/c and the number absorbed from behind per second by the same atom as: N(2) = A[Bd/(c-u)]F[(c-u)/c] = (ABdF)/c The result is the same, which shows that a moving object will absorb the same number per second of push-particles from the front as from the back. Therefore the object will feel no net force due to motion in this isotropic flux of particles. (If one worries about the energy build-up, we may assume that the particles, once absorbed, are very quickly re-scattered isotropically.) Whether I'm right or not, Have one on me! > > 2. Aberration: Suppose "pushing" particles move at a speed v, and > look at the effect on the Solar System. For a planet at distance d > from the Sun, the "push" will not be toward the instantaneous > position of the Sun, but towards its position at a time d/v in the > past. This is a drastic effect -- if v is the speed of light, the > Solar System would be drastically unstable over a thousand-year > time scale. > > (The effect of aberration is to increase the velocity of a planet, > and you might hope that drag would cancel it. But it's easy to > check that such cancellation can occur at, at most, one radial > distance from the Sun.) > > 3. Principle of equivalence: It is observed that gravity acts not > only on mass, but on all forms of energy. A "push gravity" theory > would have to come with an explanation of how the particles that do > the pushing manage to push against, for example, electrostatic binding > energy and the kinetic energy of electrons in an atom, and why that > "push" exactly matches the "push" against ordinary matter. > > In particular, we observe that gravitational binding energy itself > gravitates. This seems to require self-interaction among the > pushing particles. On the other hand, the accuracy of the inverse > square law over long distances requires that the self-interaction > be very small -- you certainly need a mean free path larger than > the size of the Solar System if you don't want to mess up Pluto's > orbit. > > 4. Gravitational screening: There are very strong limits on the kind > of "gravitational screening" one would expect from a "push gravity" > model -- see, for example, Unnikrishnan et al., Phys. Rev. D 63 (2001) > 062002. > > [...] >> Please note, I am NOT asking about Le Sage ultramundane particles >> theory (which also falls under the push gravity category), which I can >> easiely discredit myself. I'm mostly interested in the concept of >> electromagnetic radiation pressure of high frequency radiation acting >> as the gravitational mechanism, and its shadowing creating the inverse >> square law, low pressure areas. > > You immediately run into trouble with the principle of equivalence, > for one thing. Electromagnetic waves don't interact with other > electromagnetic waves (except by truly tiny quantum effects); but > gravity bends light. Nor do electromagnetic waves interact with > internal energy, not with neutrinos; but these *are* affected by > gravity. You also run into grave problems with aberration (see above), > and very probably with drag. You would *further* have to explain why > this high frequency radiation is not absorbed by the Earth enough to > lead to gravitational screening of the type ruled out by experiment. > > Note that "high frequency [electromagnetic] radiation" is gamma radiation. > There are experimental measurements of very high energy gamma rays, and > a fair amount is known about their spectrum. I suspect you would have > a very hard time reconciling your model with these observations. > > Steve Carlip >
Richard Saam <rdsaam@att.net> wrote: > carlip-nospam@physics.ucdavis.edu wrote: > snip >> Electromagnetic waves don't interact with other >> electromagnetic waves (except by truly tiny quantum effects); > snip > Could you please provide a reference to: > "truly tiny quantum effects" > of > "interacting Electromagnetic waves" One place to look is www.hep.ucl.ac.uk/opal/gammagamma/gg-tutorial.html. For observations involving real (not virtual) photons, see, for example, Burke et al., Phys. Rev. Lett. 79 (1997) 1626 and Bamber et al., Phys. Rev. D 60 (1999) 092004. There is even a proposal to build a photon- photon linear collider -- see, for example, www.desy.de/~telnov/ggtesla/ and diablo.phys.northwestern.edu/~mvelasco/gg-papers.html. For a description of the process in QED, you can look at most quantum field theory textbooks, under "photon-photon scattering." For example, see section 7-3-1 of Itzykson and Zuber. Steve Carlip
Steve Carlip pointed out that > Electromagnetic waves don't interact with other > electromagnetic waves (except by truly tiny quantum effects); Richard Saam <rdsaam@att.net> asked for references for this. The usual phrase for this is "photon-photon scattering". A brief bout of googling this phrase found (among others) the following pages which look quite informative: http://www.madsci.org/posts/archives/feb99/919892082.Ph.r.html http://www.hep.ucl.ac.uk/opal/gammagamma/gg-tutorial.html http://arxiv.org/abs/hep-ph/0512033 The last of these is an M.Sc thesis on the possible observability of this. Cheng and Wu, Phys Rev D 1, 3414 (12 June 1970), http://prola.aps.org/abstract/PRD/v1/i12/p3414_1 give a detailed calculation of photon-photon scattering cross sections. Chiao, http://www.physics.berkeley.edu/research/chiao/EOY00/chiao6.pdf gives an experimental observation, abeit in a dilute gas rather than in a vacuum (which would be a "purer" situation). ciao, -- -- "Jonathan Thornburg -- remove -animal to reply" <jthorn@aei.mpg-zebra.de> Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut), Golm, Germany, "Old Europe" http://www.aei.mpg.de/~jthorn/home.html "Washing one's hands of the conflict between the powerful and the powerless means to side with the powerful, not to be neutral." -- quote by Freire / poster by Oxfam
1. In GR I thought that gravity propagates (insofar we can talk about gravity propagating) also at the speed of light, and not instantanious, like Newton. Why doesn't the solar system becomes unstable then? Is in GR the gravitational pull towards the instantanious position of the Sun? (As explained to me somewhere else, GR handles this properly, and therefore the expected results for GR and Newton are in fact the same in most cases (with the exception for example of Mercury), even though in GR gravity is not instantanious and in Newton the effects of gravity are instantanious). 2. The shielding by the Sun of planet at distance d circling the sun happens not only at the present position of the planet, but at every location at distance d. At every point (wether occupied by a planet or not) some shielding occurs because of the shielding effect of the sun. And vice versa. So, I don't see how that is going to affect the direction of the netto pull that occurs, it would be in the right direction. Conclusion: The argument is not valid. Not that "pushing gravity" is a viable assumption, as there are - even when the math would show that is equal to GR - detectable differences. And many thing are not explained, like do these particles interact with matter elastically or inelastically, are the particles themselves massless and traveling the speed of light?, etc..