To Sylas & Nereid: I’m growing a little weary of the thread myself, so you’re in good company

One thing keeping it afloat, however, is that there is no mainstream answer to the problem. DEILE model could be wrong, but until something better one comes along…

Adding to the difficulty in sinking DEILE model is that it is an extension, not a guess. That is, most other proposals to explain luminosity-redshift curve (i.e. “acceleration”) make a guess that “something” is not as it appears. Perhaps c is not constant…maybe G changes with time. They show that such a hypothesis produces a “pretty good fit.” Then Sylas carves up the results.

But DEILE is not a guess at what could be, it is an extension of what is. The effect of sunlight in the solar system—relative to its absence—is to cause the average distance between objects to increase…dust the most. DEILE merely extends this observation to infinity…and it is hard to prove a negative. It is hard to prove that what we see happening in solar system has nothing to do with what we see happening at infinity

DEILE also is an extension of the duality. All finite gravitational systems have dualistic tendency: the central, dense region grows denser; the spacious, outer part(s) grow more spacious. Again, it is difficult to prove the contrary that the duality does not end on expansion at infinity.

The above questions/objections revolve around the extent of the extension: Sure, radiation can push dust around; but galaxies? The skepticism may be well founded.

Frame-dragging is a good analogy of what I mean by that. I could argue that frame-dragging (from GR) is causing the moon’s orbit to expand. I would be “correct” in the sense that frame-dragging is real, and in the earth-moon system it causes moon’s orbit to expand. But I would be incorrect in stating that frame-dragging explains the observed 10E-10/yr expansion, because—as I recall—frame-dragging has an effect more than 1000 times smaller than Newtonian tidal effects. So frame-dragging is real, and it would have a small net-expansive effect in earth-moon system, but it does not explain the all of it…not even 1/10th of 1 % of it.

In like manner, the effect of radiation I am describing should produce a small, non-zero net expansion. It may not explain all of observed expansion; it may not even explain 1/10th of 1 % of it. But radiation has some small, expansive effect. This effect—whatever its magnitude—must be taken into account before we turn to other explanations.

As to how dust pushes back, as Nereid would suggest, we invoke laws of physics on an as-needed basis : conservation of linear momentum. When a photon gets absorbed by dust particle, a certain quantity of linear momentum, hv/c, or something like that, is imparted to dust particle. We can, in principle, trace the origin of this back to some other quantum system in the sun that emitted photon. It recoils; it loses the linear momentum the dust gains. The force of radiation pressure on dust is therefore equal and opposite to force exerted on sun. The sun’s radiation pushes outward with 70 trillion pounds of force, and the universe pushes back equally

Granted, 70 trillion pounds of force is “almost nothing” in the grand scheme of things. But every star in universe is doing likewise. So to model universe, you have to model infinite centers-of-gravity all “pulling” against each other gravitationally, and all are “pushing” against each other radiantly (because centers-of-gravity tend to get hot and radiate like hell). So what happens in the sea of infinite time and space, with an infinite number of centers-of-gravity all pulling and all pushing? The long-term result of this tug-of-war between push and pull is not immediately obvious, but with a little reflection, we should not be surprised at what we see: dense regions growing denser and spacious regions growing spaciouser.

And Yes, Nereid, dust is transparent to gamma and radio waves. Every substance has its “absorption spectrum.” Dust just happens to be particularly absorbent near the peak emission range of most stars, and hydrogen particularly transparent. But all-and-everything makes some contribution, at some wavelength, at some distance. It is said that it would take 10 light-years of lead to stop neutrinos. Well, between here and infinity lies 10 lys of lead. The neutrinos the sun spews forth make an impact…though it be far, far away. Space is nearly transparent to many types of radiation, but it is not perfectly so to any. Every part of the 70 trillion pounds of force the sun puts out makes an impact somewhere, sometime.

For DEILE model, the effect of this outward-directed radiation pressure is crucial. Here is an instance where DEILE model apparently flatly contradicts known laws of physics:

Typical Mainstream Description: "The star was found to have a ring of dusty debris in 1983 along with some other young stars (Jean Cote, 1987). Then, in 1991 astronomers learned that this debris ring was unusually warm and close to its parent star, unlike other disks that are farther out and so colder (Aumann and Probst, 1991, pp. 266 and 269). This dust, given its known properties, should spiral into a star within 20,000 years, according to current theories of physics and star formation. "[emphasis added]
source

I do not know what exactly they took into consideration in their “current theories,” but there are at least 3 factors at work:
1. Orbital velocity of dust
2. Size of dust
3. Radial velocity of radiation field

Number 3 is typically left out in explanations of the effect, e.g. wikipedia. When #3 is taken into consideration, conclusion is that only dust very near the star will spiral in. In the case of our sun, this condition is met only well inside Mercury’s orbit. This subtlety—that real radiation sources rotate, and therefore, their radiation fields, too—completely changes the picture.

I do not know the particulars of Zeta Leporis, the star in question in the above quote, but in general, the region close to a star where orbital velocity exceeds relative velocity of the radiation field is small and finite, whereas the region where orbital velocity is less than the velocity of the radiation field is large and infinite. Ergo, in general, of the two forces at work—outward-directed radiation pressure and inward-acting Poynting-Robertson drag—radiation pressure is going to win more often than not. Ergo, the general tendency of radiation is to push bodies away from the radiation source, as comet tails demonstrate, not towards it, as above sources suggest.

Finally, as to how it can move galaxies: I’ve already described how dust—being pushed away from any bright source—tends to gather between stars where radiation is equal in all directions. Following this logic, dust should get expelled from the galaxy…except gravitational tug of gas in the disc hauls it back in.

Thus radiation field between galaxies couples to dust within them, which is gravitationally coupled to gas, which is coupled to the stars. Ergo dust acts as a buffer, coupling reaction-force to galaxy as a whole. So all the galaxies in universe are not only pulling on each other gravitationally, they are all pushing against each other, radiantly.

In GR, radiant energy is an attractive force, like matter. As with dust, which “in theory” should spiral into the sun but is observed to spiral away, I believe there is something being overlooked. I am not sure what it is, but my understanding is that GR is a “general” theory and does not take into account specifics of electromagnetic and other types of radiation.

Cosmologists keep looking for an “anti-gravity” force. Well, virtually every visible object in the universe is a source of anti-gravity force—the sun’s contribution being about 70 trillion pounds. When the anti-gravity effect of starlight is shown to be not enough to explain observed expansion, then we look for “exotic” energy sources. Then someone can give DEILE hypothesis the coupe de grace.

But as it stands—to my understanding—radiation in GR produces an attractive force, not an expansive one, hence there must be “something else” (i.e. DE) producing the expansive force. As with the pre-1998 “slowing” of expansion, the mainstream does not even have the “direction” of radiation pressure right. I just don’t see how the effect of radiation—which under local conditions has an irrefutable expansive effect—can have the opposite effect under GR. It just does not add up.

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PW -- Plant Whisperer

Pete, can you say anything about the effect of pressure on the evolution of the universe?

As good an example of the pitfalls of 'word salad' physics if ever there was one.

First, H is most certainly NOT transparent, blue-ward of the Lyman limit.

Second, 'most stars' is irrelevant (or, if you prefer, marginally relevant); what counts is the integrated SED of a galaxy ... to which 'most stars' contribute little (they're too dim), and where they do contribute (in the infrared), 'most dust' is transparent.

Third, at least in rich clusters, stars (and dust, and all the mass in galaxies) is pretty much irrelevant ... the known mass of inter-galactic gas (actually plasma) far exceeds that of the mass in galaxies.

Fourth, in terms of numbers of photons, the CMB outnumbers all the emissions from all the stars, dust, galaxies, hot plasma, cold gas, ... combined (and dust is essentially transparent to the CMB .... except, of course, that it radiates in this waveband!)

Fifth, outside of spiral and (some) irregular galaxies, there is (essentially) no dust.

(and so on).

So if dust is so important, then why doesn't DEILE work ONLY on spiral (and some irregular) galaxies? And why isn't hydrogen gas far more important in star-burst galaxies (where the SED is dominated by UV, from the massive stars in the star-bursts)?IIRC, we had a look at this, earlier in this thread, and concluded that it holds no water ... "this outward-directed radiation pressure" can be relevant only where it is absorbed ... which is by dust, which occurs only in spiral (and some irregular) galaxies ....

Nereid: If I should concede all of the above objections—I won’t but if I did—you would have succeeded only in “whittling down” the interaction by an OOM or two. Perhaps I would have to concede, “Ok, the sun’s ‘effective’ anti-gravity force is only 1 trillion lb-f, not 70.” The argument still stands: every shining star in the universe is putting out an anti-gravity force as well as a gravitational one.

If we follow the process occurring in sun, something like 4 million kg of mass is converted into radiant energy every second. Neutrinos escape immediately, but photons take 10,000 years (or is it 10 million?) to reach sun’s photosphere where, having greatly multiplied in number, they finally escape. In GR, radiant energy still has a gravitational effect, so this radiant energy “pulls” gravitationally the whole time it is traveling to the surface. In fact, photon still has gravitational effect (on universe at-large) when it leaves sun’s vicinity.

My argument is that GR is about gravity, and does not take into account reaction-force when light and dust (or any material) interact, because that is a quantum-mechanical interaction. And to my understanding, mainstream concedes there is no clear-cut bridge between GR and QM.

What stars are fundamentally doing is converting energy from a form we cannot see—potential—into one we can: radiant. That’s why the visible universe is visible. Said energy has a gravitational effect no matter what form it is in, but when it transforms from potential to radiant, it acquires an anti-gravity attitude. It’s small, but non-zero; the situation changes. The energy is no longer in a form that is only pulling—it is now pulling and pushing.

Consider 4 hydrogen atoms before they fuse in sun’s core: they exert a purely gravitational effect on the rest of the universe proportional to mass of 4 H atoms. After they fuse, the 4 baryons in He nucleus, plus radiation from reaction, exert the same gravitational force on rest of universe equal to 4 H atoms. But some of that energy, having been converted into radiation, now has acquired an “anti-gravity” effect, and contributes to sun’s 70 trillion lbs of outward-directed force.

Deep within the sun, the average distance between baryons is decreasing. This is accompanied by tremendous release of energy. A short distance beyond sun’s photosphere, the flip-side of this situation is observed: the average distance between baryons is increasing—being visibly evident in comet tails and measurable in the proton content of solar wind.

Extend this observation to infinity and the picture makes sense: within and around each of an infinite number of stars, there is a surface below which average distance between baryons is decreasing, but above which average distance-between baryons is increasing. Call it an “action-horizon.” On the inside, things are getting closer together; on the outside, things are getting further apart. Inside the horizon, due to energy-distance relation, the coming together is associated with tremendous release of energy; outside it, expansion is associated with small gain in energy.

Stars shining and universe expanding at first glance appear very different, but upon closer inspection are opposite sides of the same coin.

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It is said that BBT rests on three observational pillars:
1. Hubble Expansion
2. Cosmic microwave background
3. Nucleotide abundance ratio

As well, DEILE rests on three observational pillars:
1. Radiation has an anti-gravity effect, as evidenced by comet tails pointing away from sun
2. Stars are in the business of converting matter, which has purely attractive force, into matter-plus-radiation, which has attractive-plus-repulsive force
3. Dualistic nature of gravitational systems in general

DEILE model does not address 2nd & 3rd pillars of BBT, and has been criticized for that. But like BBT, DEILE’s purpose is to explain 1st observation—Hubble expansion. BBT ignores all 3 pillars of DEILE…DEILE can ignore 2 of the BBT’s! Mainstream points to observations that support BB model; I point to observations that support DEILE.

At this juncture, questions and objections revolve around demonstrating that magnitude of effect is sufficient to produce observed expansion. All you’ve really done so far is some hand-waving to argue there is an infinitesimal reaction-force—and held up as “proof” comet dust. Until you put up some numbers, showing how this vaporous interaction can move galaxies, there’s no need to take your model seriously.

I have put up numbers—in terms of energy—and they are overwhelmingly in support of DEILE. Of course, I see above objection from the other side

Mainstream: We will continue to disregard anti-gravity effect of radiation and duality of gravity, per DEILE, in favor of exotic explanation, until such time as Mr. Wilson can show these prosaic effects have a measurable impact.

Mr. Wilson: I will disregard “exotic” explanations of expansion, until such time as someone can show the prosaic effects of radiation pressure and duality have an immeasurable impact.

The Perfect Stalemate.

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PW -- Plant Whisperer

If the DEILE interaction has 'merely' been whittled down by and OOM or two, and if, in the original version, it nicely matched the observational data (as you claimed), won't it now fall short - by an OOM or two - of matching that data?

Pete, do you have any OOM estimate of the pressure required to observe the effects seen?

Briefly...no.

The only way I have been able to figure out how to get a handle on the problem so far is in terms of energy, not force.

I can try to make some "ballpark guesses," but it will take time.

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PW -- Plant Whisperer

Do you mean that you have it in terms of energy density?

I have no idea how to calculate actual reaction-force of radiation vs. gravitation. I only notice its effect in the solar system, and surmise there must be relation between what we see near by and what we see far away. Think of Drake equation with many variables. You’re arguing with degree of influence of 2 or 3 of them. I shrug.

One of the variables, however, is star-formation rate, which is observed to be falling. As I understand Sylas' analysis, for exponential model to match data, H cannot be “constant,” but must fall by 6% (or something) per billion years, which is in the same neighborhood as drop-off in star-formation rate. It is this prediction of DEILE that is within 1 OOM of observations, but more to my relief, at least in the right direction!

As for how all the other factors enter into calculation of H: that is what I am uncertain of to many OOMs. The influence of one variable—star formation rate—is in right direction and to within 1 OOM, but I have no idea if the sum-total influence of the many variables is correct within any number of OOMs.

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PW -- Plant Whisperer

What I mean is, when I do the energy estimate, there is enough energy to drive expansion; when I do the force estimate, however--as most people would guess--radiation pressure is not up to the task.

I suppose most people would conclude, "End of subject," and move on. As indicated above, I am almost ready to myself However, small voice keeps saying, "Don't give up," and the topic remains intriguing because there is no accepted answer to the mystery.

In the popular reckoning, main difference between Newton's gravity and GR is tossing out absolute notions of space and time: both can bend and stretch, boggling the mind. But as for the problem of expansion of space, the problem with Newton's gravity is that it does not deal with infinity: Newton simply lacked the mathematical tools necessary to take on infinity. These tools (tensor-matrix algebra and the like) are over-my-head, so I am stuck trying to solve infinity problem with finite math...and results are unconvincing, to say the least.

Calculating the gravitational energy of a two-body system is trivial. I assume everyone understands that calculating the energy of an infinite-body system is much more difficult. The only way I can wrap my mind around the infinity problem, is on a per-kilogram basis.

The energy-output side of the equation—on a per-kilogram basis—is intuitively obvious: we can see so-much energy being radiated by visible matter, and Newton’s laws tell us there is so-much mass out there, so you simply divide energy output by mass. But how much energy is involved in the expansion? It is equally obvious this is much more difficult. Equations of GR give you an answer, but are not expressed in per-kg basis, however, so I do not know what they are saying in the paradigm I understand. And GR—to my understanding—does not include duality, nor reaction-force described above, so I am mistrustful of its results…besides the equations being in a different paradigm.

But back to mechanism problem: if radiation pressure is enough to move dust, but not galaxies, how can it be causing expansion of space?

I have to admit, I am almost out of rope here…but the usual caveats apply: infinity can be very counter-intuitive. I have done the estimate another way, and while I will not claim to have done it “right” this time, the answer I get I find very intriguing. If I can manage to explain why I find it so intriguing, perhaps those who—like me, are a little intimidated with tensor matrix algebra—will find it interesting also.

Briefly, my estimate goes like this: radiation pressure is not enough to move galaxies at observed rate. However, when doing the energy estimate in Newtonian terms, a paradox arises. And the only way out of the paradox—that I can see—is to have space expand, per GR. So I am left with a mystery: force estimate says radiation no-can-do expansion; energy paradox of radiation, however, says space must expand. So I can get no further than my “grain of truth” position outlined a few posts back, that radiation has to have some expansive effect, but it may not be enough to explain the observed expansion rate.

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PW -- Plant Whisperer

What I am saying is, the on-going process of star formation and nuclear reactions in their cores transforms energy from one form (potential) to another (radiant).

When an elevator goes down, it loses potential energy, and when a star shines, it loses potential energy. Likewise, when an elevator goes up, it gains energy, and as the universe expands, it is in effect "going up," i.e. gaining energy. What I am arguing is that energy being gained by universe as it expands comes from the energy being lost by the stars as they form and shine.

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PW -- Plant Whisperer

There's another aspect of DEILE which I'm not sure whether we've covered - the '5 Mpc' scale length (within ~5 Mpc DEILE says contraction, beyond ~5 Mpc DEILE says expansion; or something like that).

I don't remember - does ~5 Mpc come from some derivation (within DEILE)? Or is it simply what we observe (and so is yet another thing which DEILE needs to show is consistent)?

ok, seperatly, wat is light energy and wat is dark energy?

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SAO <3's S.C.W.

Light energy is radiant energy put out by stars, and is what we see when we look up at the stars at night.

Dark Energy (DE) is a term, in equations of General Relativity, required to reconcile theory with observed accelerating expansion.

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PW -- Plant Whisperer

As I recall, it is distance at which relative motion of galaxies within a cluster--up to 300 km/s--is overtaken by Hubble expansion.

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PW -- Plant Whisperer