It's a very fortunte thing since Chris is a guy who knows what he's talking about. I'm on the other hand a sculptor who got himself into cosmology through an accident. This accident was a result of my calculaton of the density of "Einstein's universe" (static, more properly called "stationary") that turned out to be in the middle of estimets that were 1 to 10 while my result came as 3 (in units of 10^{-27}kg/m/^3). Since my calculations were based on Hubble redshift (50 km/s/Mpc then and I just wanted to know how much of it is due to density of the universe because of gravitational friction of photons) after I got this result I started to suspect that the whole Hubble redshift is (kind of) due to dynamical friction of photons. After some discussions with mathematicians (like Chris Hillman), physicists, astronmers, and cosmologists and reading some of their books this suspicion of our universes being Einstein's deepened (to make a long, over 22 years old story, short).

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Hi Chris, I'm impressed by your memory if you still remember me. I hope you don't pretend any more that you are just a computer program (Jonh Baez gave you out).

Yes, however my understanding of Einstein's gravitation prevents me from thinking that there is such a thing in nature as "gravitational attraction". Actually, I'm puzzled why you even mentioned it since you must know that Einstein's gravitation does not allow gravitational forces acting at the distance. Gravitational forces exist only as tidal forces when particles press against each other because of their inetia (that's why they are called pseudo forces) or e.g. your butt presses the Earth when you happen to sit on the Earth.

It can be easily shown with differentiating E=mc^2 along distance (taking dE/dx and showing in about 5 minutes that it is equal -mg, just try it substituting -g/(2c) for dc/dx as it follows from Einstein's accelerating rocket or elevator, and from his equivalence principle).

It prevents it observationally: if energy is consered the universe is not observed to be expanding since there is no Hubble redshift left for the expansion. The whole 70km/s/Mpc is used for the dynamical friction of photons that generations of cosmologists thought it is "negligible" without ever calculating it exactly. Try to calculate it then you'll see for yourself. It should take a smart mathematician less than an hour. I did it in about eight, once I gave up all the unwarranted approximations. Now I demonstrate it to professors in a few minutes, so they rescue themselves by claiming that energy is not conserved in GR. As John Baez did in the same situation, dispite that you don't believe it. And he even tried to convince me that the kinetic enery of a falling brick comes from nowhere (when I asked him directly about it). And that's why I had to figure it out myself and now I know where it comes form. Though only one professor in my university agrees that it my explanation is strictly what Einstein's must have meant.

As I said, if you try to ignore dynamical friction of photons you need to supply energy to keep Hubble redshift to be the result of expansion. Is there any error in such a reasoning?

Of course it is not true since it would require just a one good kick, but if you want the same ball moving through the universe it is subject to dynamical friction and then it needs constant injection of energy to counter the dynamical friction. With photons it is even worse since it is not a Newtonian effect but purely relativistic. And so it is not some mysterious "tired light effect" but the effect of time runing slower at their origin similarly as reqired also by the regular gravitatinal redshift. Only that in the Hubble type redshift it turns out not quadratic with distance but exponential. And that's why it carries with itself the illusion of accelerating expansion with acceleration that is actually observd since it's theoretical value is H_o^2/2 (second term of Taylor series, first is H_o) while observed value is 0.45 H_o^2 (at least it was like that last time I looked at the data).

I might and that's why I'd like smart people in this forum to tell me what it might have been.

I appreciate this, however also I like Feynman's approach when he says: "Let me also say something that people who worry about mathematical proofs and inconsistencies seem not to know. There is no way of showing mathematically that a physical conclusion is wrong or inconsistent. All that can be shown is that the mathematical assumptions are wrong. If we find that certain mathematical assumptions lead to a logically inconsistent description of Nature, we change the assumptions, not nature."

I think that conservation of energy is true in any frame and a total energy of the particle is its Mc^2 (M being total mass, including its kinetic energy) which does not change with its position, and its so called "gravitational energy" is mc^2 (m being rest mass), that may be radated out on occasions, most likely just in photons. It isn't relevant here since it does not change anythng in the mechanism of Hubble redshift. The mechanism is the slowing of time exponentially with the distance to the source of light to compensate for the curvature of space which produces an easily derived relation that d^2T/dt/dx + 1/R = 0, where T is proper time, t coordinate time, x is distance, and R "radius of curvature of space" (all derivations are in my paper quoted at the first message).

Of course it produces Hubble constant H_o=c/R. Which happens to be observed if R=4.3 Gpc. What is not observed is about 57% of the mass of the universe required to produce average density needed for conservation of energy to work. One reason why my professors maintain that energy "is not concerved in gravitation". What do you think?

Might be. I think I mean "Ricci flat" but I'm not sure if it is what I mean since I never heard the term. I mean that the contraction or Ricci tensor gives zero. If you mean the same than it is "Ricci flat". I support it by hypothetizing the existence of a 3-D tensor (which I called "general time dilation tensor") that with 3-D Ricci tensor adds to zero. But not being a mathematician I might do here something silly. However it comes out from the above d^2T/dt/dx + 1/R = 0 generalized over all 3 spatial directions after multiplying it by R. I think that as for a sculptor I did anough work to make it interesting for a mathematical physicist to take it over and fix all mistakes, since I think that physics is right here. Yet Phys. Rev. Lett. editors maintain that lack of any new physics in it makes it uniteresting to their readers. So it can't be even published. And BAUT forum is the only available place where it can be kept for one month. Except of course my web page which nobody reads. So I can't even learn what are the objections against the "Einstein's universe" dispite that it sems to be physically viable proposition.

But notion of gravitational energy in gtr might be wrong and according to what I said above it is since if (d/dx)(mc^2)=-gm then mc^2 is the only "gravitational energy", and it is localized. And it can be also radiated out because it changes by quanta of energy (photons in this case). So I don't see problems with localizing it. Why do you say it can't be localzed?

You are not mean. You just say what you think that is right and I'm telling you why I think my way. I'm not concerned with my PhD at all. I'm just using it as a vehicle to find the truth about the universe. I've seen so many stupid things in literature, contradicting not only Einstein's theory (like e.g. existence of "gravitational attraction") but also contradicting the common sens (like lack of conservation of energy in gravitation) and revealing that the authors don't know physical facts, that I stopped beliving text books (and I have over 20 kg of them, since I trusted them once, starting with MTW that I bought first). And it is difficult to learn if you don't trust your teacher. So I can learn only through a dialog, and if you convince me that truth is different than I thought, that the universe expands, it would be great. I like to learn things that I didn't expect being true. It is the gratest thing in science. Untrue science is like a kitsch. I just suspect cosmology being a kitsch not science. And only since cosmologists (at least in my U and on the internet) say "we won't talk to you unless you give up that nonsense that energy can be conserved in gravitation". But if it is conserved then "Einstein universe" can handle quite nicely the illusion of accelerating expansion, CMBR, and presumably other things that I don't know about, so I'd like to learn which things it can't handle.