Guy Grantham emailed me a link to a detailed fairly new Wikipedia page on the old ideas of LeSage, http://en.wikipedia.org/wiki/Le_Sage%27s_theory_of_gravitation. I think it’s badly done (for detailed comments of mine see the post http://electrogravity.blogspot.com/2006/03/george-louis-lesage-newtonian_26.html on my old blog, and its comments, because there is a comment quoting evidence that LeSage may have deliberately plagarized a lot of unpublished research of Fatio’s, who was a friend of Newton – Newton didn’t like the ideas because they were too half baked at the time and didn’t make quantitative predictions), because the dismissal of exchange radiation for gravity on the basis that it would heat up bodies thermally if the exchange radiation was intense enough to cause the forces is vague enough to also dismiss Feynman’s diagrams showing that the best physical theory that exists, the Standard Model, works by exchange radiation causing fundamental forces! In particular, the Standard Model forces are all much stronger than gravity, so any thermal heating would be even more severe than in the case of gravity. So that objection is bunk. Similarly, if exchange radiation is considered to disprove LeSage by causing drag, it also disproves string theory which claims that spin-2 graviton exchange radiation between masses causes gravity.
Heat occurs when radiation is received by the oscillation set up in a charge due to the fields in the radiation. Thus, a radio wave causes an electron to oscillate, and the resistance to the motion of the electron in the metal or whatever, causes some heating. That’s the basic mechanism whereby radiation energy can be converted into kinetic heat energy in matter. This mechanism doesn’t hold, however, for extremely high energy radiation. A gamma ray has a wavelength too short to merely oscillate electrons, and behaves more like a particle when it hits matter (although it behaves like a wave when travelling, hence the interference pattern which results from the double slit experiment using even single photons). The gamma ray imparts energy by knocking into charges, and ejecting them from the material if they have enough energy to do so (the photoelectric effect), Compton scattering (where the incident gamma ray is degraded in energy and changed in angle, imparting some energy to the electron like a billiard ball collision), and pair production (where the gamma ray has enough energy to create a free pair of particles from the Dirac sea).
It’s clear from experience that whatever the detailed mechanism for Yang-Mills exchange radiation is, it doesn’t cause things to heat up. The claim that the energy locked up in fields must be turned to heat by masses is absurd. This is because heat energy is different to field energy. An electron has an energy of 0.511 MeV. This energy is locked up but can only be released by annihilation with a positron to give two gamma rays, each of 0.511 MeV. However, it would be wrong to ridicule the existence of electric field energy by claiming that if electrons had a rest mass energy of 0.511 MeV, matter would get very hot indeed. The claim that exchange radiation of a field is the same thing as heat energy is totally false. The two are completely different.
Feynman chose the LeSage gravity mechanism, out of all discarded gravity mechanisms, as the one to describe in detail in his Lectures on Physics, and it is also included with an illustration in his nice little book Character of Physical Law. Feynman shows it predicts the inverse square law but also predicts drag, which would cause the planets to slow down spiral into the sun if the radiation was intense enough to be capable of causing observed gravitation, so he concluded that it was wrong. So it is. This is also a general fault of aether ideas.
The modern quantum field theory, at least successful (non-stringy) work on it, is based on the principle mentioned in the previous post, namely Feynman’s ‘shut up and calculate’ advice. The Standard Model of particle physics is based on exchange radiation as the physical cause of forces, this is the Yang-Mills quantum field theory first proposed in 1954. Such mathematical physics is based on symmetry principles, not causal mechanism. But it is still physics, because it enables you to make calculations that can be checked, although it is not necessarily the complete story. Any final theory should mathematically correspond to Yang-Mills theory where we observe the symmetry principles to hold, but should also include some deeper understanding.
Where you could go off the deep end is to deny that there is an corresponding deeper understanding than symmetry principles.
Suppose you are given a causal mechanism that exactly predicts everything observed in the universe, but doesn’t predict the unobservable speculations of string theory. This is not going to be wrong just because the existing Standard Model and general relativity were originally derived using different ideas to causal mechanisms. Progress occurs not so much by sticking like a parrot to proclaiming the beauty of existing ideas, but by trying some new things until something useful occurs. Crackpots occur not by making calculations and finding correct new physics methods, but by people sticking to dead ends and refusing to give up false ideas, defending the falsehoods with more nonsense.
From: Nigel Cook
To: Guy Grantham
Cc: Whan Peter ; Montgomery Ian
Sent: Friday, March 16, 2007 12:03 PM
Subject: Re: objections to LeSage type gravity
Dear Guy,
Forget gravity for LeSage’s model! The LeSage model correctly explains the pion mediated strong nuclear attractive force, not gravity. Sir Karl Popper discusses how the uncertainty principle arises from impacts at high energy (i.e., in the intense electric field at small distances from a charge), in his book “Logic of Scientific Discovery”, which I quote on my homepage.
The “problems” which you get from trying to apply the LeSage mechanism to gravity become assets when you use it to explain how pion radiation via the vacuum causes protons and neutrons to be pushed together in the nucleus, if they start nearby. Fusion occurs when protons are brought close enough that the strong attractive effect from pions exceeds Coulomb repulsion, so the particles approach. Obviously, they don’t endlessly approach or the nucleus would become a singularity; instead, there is a shorter range rho particle mediated exchange which causes repulsion over smaller distances, so the nucleons (neutrons and protons) are kept a certain distance apart, something on the order 1 fm, by pion attraction at longer ranges (but with a limit of a few fm) and rho repulsion at shorter distances. Repulsion due to rhy particles is just the recoil of particles being mutually exchanged; imagine two thugs shooting machine gun bullets at each other, each will suffer a repulsion force caused partly by impacts from the other thug’s bullets, and partly by recoil (Newton’s 3rd law) of the machine gun as it fires at the other person.
Now for gravity. It’s a long range force. There are no charges in motion involved, only radiation, because pair production only occurs out to 1 fm from a charge. So gravity, which predominates at large distances, is due to exchange radiation.
Photons of light don’t interact with each other. They exert pressure when they are reflected or absorbed by surfaces because of the change in momentum p = E/c for absorption and p = 2E/c for reflection. But they don’t form a gas. Photons don’t obey the exclusion principle, so you can fit an endless amount of photons into a given space without any pressure arising!
This is why they obey bose-einstein statistics, rather than fermi-dirac statistics.
Even with water waves, you can see that there is no permanent interaction between them when they pass through one another! If you send two waves travelling in different directions through one another, they will superimpose temporarily either giving a resultant that is zero if there is “cancellation” of a peak with a trough, but after that transitory overlap each wave emerges and continues as before with its original form!
This is totally different from firing bullets at one another, where the superposition causes a permanent effect.
Unless you can see the difference between bosons and fermions and that gravity is a boson effect while the “errors” of LeSage are due to fermion radiation assumptions, we’re not getting anywhere. Once again, gravity is a massless boson (integer spin) exchange radiation effect. LeSage assumed material particles (fermions, or their composites like mesons such as pions) were the exchange radiation. LeSage’s particle assumption is only valid for pions, etc., in the strong nuclear attractive force. There, the “errors” which would be true of gravity are bonuses: the attraction is predicted to have a short range on the order of a mean free path of scatter before radiation pressure equalization in the shadows quenches the attractive force. This short range is real for nuclear forces.
For gravitation, curvature is the same thing as exchange boson radiation, and in loop quantum gravity curvature is equivalent to the effect of the full cycle of exchange radiation going from mass A to mass B and back again.
Curvature is a name for the radial contraction due to masses. To speak of curvature as being an alternative to exchange radiation causing general relativity, is as absurd as claiming that 1+1 and 2 are not the same thing. Of course they are merely different mathematical expressions for the same thing, physically. See http://cosmicvariance.com/2007/03/12/catholic-priest-proposes-new-model-for-creation/#comment-221007
‘Popular accounts, and even astronomers, talk about expanding space. But how is it possible for space … to expand? … ‘Good question,’ says [Steven] Weinberg. ‘The answer is: space does not expand. Cosmologists sometimes talk about expanding space – but they should know better.’ [Martin] Rees agrees wholeheartedly. ‘Expanding space is a very unhelpful concept’.’
– New Scientist, 17 April 1993, pp32-3.
Spacetime contracts around masses; the earth’s radius is contracted by 1.5 mm radially (the circumference or transverse dimension is unaffected, hence the fourth dimension is needed to keep Pi constant via curvature) by its gravitation. Time is also slowed down.
This is pretty obvious in cause – exchange radiation causes radial contraction of masses in general relativity, just as in special relativity you get contraction of moving masses. Take the Lorentz contraction, stick the Newtonian escape velocity into it, and you get Feynman’s simplified (1/3)MG/c^2 formula for gravitational radial contraction in general relativity (you have to put in the 1/3 factor manually because a moving object only has contraction in one dimension, whereas the contraction is shared over 3 dimensions in GR). The justification here is that the escape velocity is also the velocity acquired by an object falling from an infinite distance, so it is velocity corresponding to the kinetic energy equivalent to the amount of gravitational potential energy involved.
It’s obvious that spacetime is contracted by gravitation. Expanding space really just refers to the recession of masses, i.e., expanding volume.
All the experimentally or observationally confirmed parts of general relativity mathematically correspond to simple physical phenomena of exchange radiation in a Yang-Mills quantum field theory. (Ad hoc theorizing to model observations is not observational confirmation. E.g., dark energy speculation based on redshift observations, isn’t confirmed by the observations which suggested the speculation. A better model is that whatever exchange radiation causes quantum gravity when exchanged by receding masses, gets some kind of redshift like light due to the recession of masses, which weakens gravitational effects over large distances. OK, I know you don’t want to know all the correct predictions which come from this physics, so I’ll stop here.)
*****
‘In loop quantum gravity, the basic idea is to use the standard methods of quantum theory, but to change the choice of fundamental variables that one is working with. It is well known among mathematicians that an alternative to thinking about geometry in terms of curvature fields at each point in a space is to instead think about the holonomy [whole rule] around loops in the space. The idea is that in a curved space, for any path that starts out somewhere and comes back to the same point (a loop), one can imagine moving along the path while carrying a set of vectors, and always keeping the new vectors parallel to older ones as one moves along. When one gets back to where one started and compares the vectors one has been carrying with the ones at the starting point, they will in general be related by a rotational transformation. This rotational transformation is called the holonomy of the loop. It can be calculated for any loop, so the holonomy of a curved space is an assignment of rotations to all loops in the space.’ – Peter Woit, Not Even Wrong, Cape, London, 2006, p189. (Emphasis added.)
Professor Lee Smolin also has some excellent online lectures about loop quantum gravity at the Perimeter Institute site, here (you need to scroll down to ‘Introduction to Quantum Gravity’ in the left hand menu bar). Basically, Smolin explains that loop quantum gravity gets the Feynman path integral of quantum field theory by summing all interaction graphs of a Penrose spin network, which amounts to general relativity without a metric (i.e., background independent).
– http://quantumfieldtheory.org/
Best wishes,
Nigel
—– Original Message —–
From: Guy Grantham
To: Nigel Cook
Cc: Whan Peter ; Montgomery Ian
Sent: Friday, March 16, 2007 9:59 AM
Subject: objections to LeSage type gravity
Dear Nigel
I found a comment on the original objections to Fatio-LeSage type of gravitation that I understand you to use in modified form by the impact of (redshifted) gauge particles and their shadowing by masses. .
The Fatio-LeSage theory was criticised because the impact of inelastic particles would overheat the recipient; elastic particles would interact between themselves or be travelling in the wrong direction etc. to give regions where gravitation did not appear.; etc,etc.
The Wiki has a recent article at http://en.wikipedia.org/wiki/Le_Sage%27s_theory_of_gravitation .
Nigel, would please work through for me how the criticisms in section 4 of that article would or would not apply to your preferred theory and the ways your model differs from LeSage? I prefer to think of [can only imagine!] ‘space’ being curved rather than as a ‘particle’ impact model, or process driven like Cahill’s and Ian’s theories and really would like to get a handle on the alternative points of view.
Best regards, Guy
Quantum field theory 