Duality: Explanation of the Hubble expansion, or not?

[Peter Wilson]

Wave/Particle duality? Or are you referring to some other (presumably scientific) form of duality? And what model does not include it? How is math involved (or not)?

The duality I refer to is not the wave/particle duality, but the idea is the same: we see two apparently contradictory phenomena occurring at the same time.

Whether light is a particle or wave was debated for centuries, and the argument was finally resolved by recognizing it is both. In a parallel manner, Einstein famously “solved” his equations of GR and discovered that every possible universe would either contract or expand, depending on its initial conditions. When giant telescopes were developed, pointed skyward and the Hubble expansion was unveiled, the reaction was, “Ah hah! The universe is expanding after all!” But this is a case of not seeing the forest for the trees.

When we look to distances of less than about 5 Mpc, we do not see expansion. We see contraction. The Andromeda galaxy is on a collision-course with the Milky Way, and all the mass within the entire Local Group is caught in the local gravitational grip, pirouetting about the local center of gravity, slowly spiraling inwards. Throughout this local region, gas is contracting in myriad regions, forming new stars; and virtually every visible point of light in the sky is a center of local gravitational contraction, furiously radiating away energy as the gravitational field continues crushing matter in its ever tightening grip.

What model includes this?

Take any mainstrea model that includes math, and you will see only one distance term. It is implied, but not stated, that r in the referenced equations is > 5 Mpc. If you use an r of less than that, say 1 Mpc, the approximate distance of Andromeda, you get an answer that is completely wrong, because our local region of the universe does not participate in the cosmic expansion.

Now we take this observation and apply the Copernican Principle: we assume there is nothing special about our position, and most observers in the universe see the same thing. And in fact, we can confirm the CP by looking carefully beyond the 5 Mpc inflection point (the distance at which contraction transitions to expansion): we see galaxies colliding and clusters of galaxies that are—by all appearances—caught in a local gravitational tango, same as we are in the Local Group.

The duality is there, staring us in the face. Like the cheating spouse: how could we miss it for so long? Like the wave/particle duality, it is not one or the other. The universe is not contracting or expanding, it is doing both: two-timing us! Space is expanding at the ends of the universe, to be sure, but it is contracting right before our eyes.

As for the math, again, it is simply missing-in-action
I have argued that if you include it in your model, local contraction will show up in GR—as currently formulated—as “dark energy.” But that is just my guess. All I know is duality is not in the mainstream models. If it were, you would not be asking what it is.

The duality is reality. Once you see it, it is drop-dead obvious and it becomes impossible to not-see. But it is not yet seen by the mainstream and is not included in any model.

[Moderator Note]
The initial posts in this thread were originally in the Without math, you are not doing physics - you are merely making up stories thread; PW's OP is #10
[/Moderator Note]

[Van Rijn]

Whether light is a particle or wave was debated for centuries, and the argument was finally resolved by recognizing it is both. In a parallel manner, Einstein famously “solved” his equations of GR and discovered that every possible universe would either contract or expand, depending on its initial conditions. When giant telescopes were developed, pointed skyward and the Hubble expansion was unveiled, the reaction was, “Ah hah! The universe is expanding after all!” But this is a case of not seeing the forest for the trees.

When we look to distances of less than about 5 Mpc, we do not see expansion. We see contraction. The Andromeda galaxy is on a collision-course with the Milky Way, and all the mass within the entire Local Group is caught in the local gravitational grip, pirouetting about the local center of gravity, slowly spiraling inwards. Throughout this local region, gas is contracting in myriad regions, forming new stars; and virtually every visible point of light in the sky is a center of local gravitational contraction, furiously radiating away energy as the gravitational field continues crushing matter in its ever tightening grip.

What model includes this?

The Andromeda and Milky Way galaxies are heading towards each other, it isn't a "collapse." But in any event, at the shorter scales, gravity dominates over cosmological expansion. If it didn't, we wouldn't exist. This quantitative issue certainly isn't ignored, and in fact, there is the idea of the Big Rip where, if validated, there could come a time in the distant future when galaxies and even planets and living creatures would be ripped apart.

[Bjoern]

The duality I refer to is not the wave/particle duality, but the idea is the same: we see two apparently contradictory phenomena occurring at the same time.

Whether light is a particle or wave was debated for centuries, and the argument was finally resolved by recognizing it is both. In a parallel manner, Einstein famously “solved” his equations of GR and discovered that every possible universe would either contract or expand, depending on its initial conditions. When giant telescopes were developed, pointed skyward and the Hubble expansion was unveiled, the reaction was, “Ah hah! The universe is expanding after all!” But this is a case of not seeing the forest for the trees.

When we look to distances of less than about 5 Mpc, we do not see expansion. We see contraction. The Andromeda galaxy is on a collision-course with the Milky Way, and all the mass within the entire Local Group is caught in the local gravitational grip, pirouetting about the local center of gravity, slowly spiraling inwards. Throughout this local region, gas is contracting in myriad regions, forming new stars; and virtually every visible point of light in the sky is a center of local gravitational contraction, furiously radiating away energy as the gravitational field continues crushing matter in its ever tightening grip.

What model includes this?

Take any mainstrea model that includes math, and you will see only one distance term. It is implied, but not stated, that r in the referenced equations is > 5 Mpc. If you use an r of less than that, say 1 Mpc, the approximate distance of Andromeda, you get an answer that is completely wrong, because our local region of the universe does not participate in the cosmic expansion.

Now we take this observation and apply the Copernican Principle: we assume there is nothing special about our position, and most observers in the universe see the same thing. And in fact, we can confirm the CP by looking carefully beyond the 5 Mpc inflection point (the distance at which contraction transitions to expansion): we see galaxies colliding and clusters of galaxies that are—by all appearances—caught in a local gravitational tango, same as we are in the Local Group.

The duality is there, staring us in the face. Like the cheating spouse: how could we miss it for so long? Like the wave/particle duality, it is not one or the other. The universe is not contracting or expanding, it is doing both: two-timing us! Space is expanding at the ends of the universe, to be sure, but it is contracting right before our eyes.

As for the math, again, it is simply missing-in-action
I have argued that if you include it in your model, local contraction will show up in GR—as currently formulated—as “dark energy.” But that is just my guess. All I know is duality is not in the mainstream models. If it were, you would not be asking what it is.

The duality is reality. Once you see it, it is drop-dead obvious and it becomes impossible to not-see. But it is not yet seen by the mainstream and is not included in any model.

Ever heard of simulations of large-scale structure formation? They use the math of GR (essentially a Friedmann-Lemaitre model, i. e. an expanding universe) and use this to study the formation of structure (mainly galaxy super clusters, filaments and voids, but there are also simulations for the formation of galaxy clusters, groups or even single galaxys) - i. e. they study "collapsing" matter in an expanding universe.

So your claim that no model incorporates this is obviously wrong - physicists have been doing such simulations for about 20 years now, AFAIK, and even before computers were capable of doing this, it has been clear for decades how this works in principle.

Contrast these quantitative simulations with your entirely qualitative musings about "duality".........



BTW, bringing up the Schwarzschild metric in the context of development of the universe makes no sense at all.



And another BTW, local contraction has precisely nil to do with dark energy; it is a straightforward prediction of General Relativity / the Big Bang theory even if one does not include dark energy in it (hint: that's because of the basic fact that gravity is an attractive force). You would know that if you would bother to actually study the math behind GR and the BBT.

[Peter Wilson]

The Andromeda and Milky Way galaxies are heading towards each other, it isn't a "collapse."

Look, don't mince words.

If there was nothing beyond 5 Mpc, but otherwise everyting looked the same up to 5 Mpc, we would say, "The universe is 5 Mpc across and contracting." (According to GR as currently formulated, the universe must do one or the other: expand or contract.) It is not until we look beyong 5 Mpc that we observe expansion. So we say, "The universe is expanding."

But this is incorrect. It is not doing one or the other; it is doing both at the same time: contracting locally/expanding non-locally.

But in any event, at the shorter scales, gravity dominates over cosmological expansion. If it didn't, we wouldn't exist. This quantitative issue certainly isn't ignored, and in fact, there is the idea of the Big Rip where, if validated, there could come a time in the distant future when galaxies and even planets and living creatures would be ripped apart.

Duality, as you point jout, is observable. "The Big Rip" is pure speculation. Speculation does nothing to invalidate what is observed.

[Van Rijn]

Look, don't mince words.

If there was nothing beyond 5 Mpc, but otherwise everyting looked the same up to 5 Mpc, we would say, "The universe is 5 Mpc across and contracting." (According to GR as currently formulated, the universe must do one or the other: expand or contract.) It is not until we look beyong 5 Mpc that we observe expansion. So we say, "The universe is expanding."

But this is incorrect. It is not doing one or the other; it is doing both at the same time: contracting locally/expanding non-locally.

Rather, expansion is observable at larger scales, gravity dominates at smaller scales. There isn't a "5 Mpc" line in the sand, and expansion as well as gravitational force are accounted for.

Duality, as you point jout, is observable.

I would hardly call the interplay of expansion, gravity and other forces, "duality."

[Peter Wilson]

Ever heard of simulations of large-scale structure formation? They use the math of GR (essentially a Friedmann-Lemaitre model, i. e. an expanding universe) and use this to study the formation of structure (mainly galaxy super clusters, filaments and voids, but there are also simulations for the formation of galaxy clusters, groups or even single galaxys) - i. e. they study "collapsing" matter in an expanding universe.

So your claim that no model incorporates this is obviously wrong - physicists have been doing such simulations for about 20 years now...

Really? Then why did nobody see the accelerating expansion coming?

If Jupiter's orbit is contracting, then the orbit of some other planet(s) must be expanding!!! (The duality.) Conservation of energy and angular momentum dictate this. Apply this principle to the universe at large, and the result is the same: if the universe is contracting locally everywhere, then some other parts (non-local) must be expanding!!!

If duality were incorporated into mainstream models, the accelerating expansion would have been predicted; the mainstream would not have been caught by surprise.

Contrast these quantitative simulations with your entirely qualitative musings about "duality"...

My point is, the mainstream model is all mathematical, but it leaves out duality. A math model which leaves out an essential feature does not count as "quantitative."

And another BTW, local contraction has precisely nil to do with dark energy...

In your opinion.

...(local contraction) is a straightforward prediction of General Relativity / the Big Bang theory even if one does not include dark energy in it...

No.

The prediction from GR is that space either contracts or expands. Predictions aside, it is observed to be doing both.

[Bjoern]

Look, don't mince words.

If there was nothing beyond 5 Mpc, but otherwise everyting looked the same up to 5 Mpc, we would say, "The universe is 5 Mpc across and contracting." (According to GR as currently formulated, the universe must do one or the other: expand or contract.) It is not until we look beyong 5 Mpc that we observe expansion. So we say, "The universe is expanding."

If there was nothing beyond 5 Mpc, the universe would not be homogeneous, and we would need another model instead of the now-used Robertson-Walker metric.

But this is incorrect. It is not doing one or the other; it is doing both at the same time: contracting locally/expanding non-locally.

Technically, you are correct. But cosmology deals only with the behaviour of the universe "as a whole", i. e. on very large scales. When one talks about the behaviour of the universe "as a whole", local effects are simply neglected.
"on the whole", the universe is expanding.

But that obviously does not mean that cosmology is entirely ignoring the more local effects - as I already pointed out.

[Bjoern]

Hello, Peter. Nice to see you here again. What happened to our discussion in the other thread? (Dark energy Dark matter)

Really? Then why did nobody see the accelerating expansion coming?

Err, because this has nothing at all to do with the accelerated expansion. I know you think otherwise - but in contrast to standard physics, you have not supported that assertion in any way so far.

If Jupiter's orbit is contracting, then the orbit of some other planet(s) must be expanding!!! (The duality.)

There is no duality in the form in which you propose it.

Conservation of energy and angular momentum dictate this.

Show your math. Don't forget to include the energy and angular momentum contained in the sun, and in the interplanetary gas etc.

Apply this principle to the universe at large, and the result is the same: if the universe is contracting locally everywhere, then some other parts (non-local) must be expanding!!!

No, that's a non sequitur.

Again: show your math.

If duality were incorporated into mainstream models, the accelerating expansion would have been predicted; the mainstream would not have been caught by surprise.

Show your math: how does duality predict an accelerated expansion?

My point is, the mainstream model is all mathematical, but it leaves out duality. A math model which leaves out an essential feature does not count as "quantitative."

Well, what about showing first, quantitatively, that your "duality" exists and can account for the acceleration?

In your opinion.

If you think otherwise: provide evidence that it does. I. e.: show your math.

No. The prediction from GR is that space either contracts or expands.

Wrong.

The prediction from GR for a totally homogeneous universe is that it either expands or contracts. However, the prediction from GR for a universe with density fluctuations is that even if the universe on the whole expands, these fluctuations will "contract" (on smaller scales).

In the pop-science literature, you will almost always find only the first prediction. Suggestion: try reading some real scientific papers (or at least a textbook) on a theory before attacking it.

[Peter Wilson]

I'm gonna start another thread on duality here in a bit. We'll take these issues up there.

[Peter Wilson]

The raison d'être for the BA part of BAUT is to shoot-down astronomical misconceptions. I have put a concept on the table—duality—that purports to explain the expansion of the universe, and it remains undebunked...at least in my estimation

While mistakes were made in the original exposition, all but one were immediately caught by the readers, and all but one were immediately acknowledged and corrected by author…call the score even. Since all reported errors have been rectified, the conception/misconception sits in limbo. You can help decide the proposition.

What is Duality?

Duality is the observation that the universe is neither expanding nor contracting, but doing both at the same time, i.e. is contracting locally while expanding cosmically. It is my contention that mainstream models do not incorporate duality, and if they did, it will be seen that the cosmic (Hubble) expansion is merely the flip-side of local contraction.

Perhaps part of the difficulty is the fact that contraction and expansion manifest in different ways, and it is not at all immediately obvious that they are related.

--The universe is expanding at the rate of 2.3E-18/s (72 km/s/Mpc) at distances of greater than 5 Mpc,
--The universe is contracting at the rate of 1.0E-8 j/kg/s at distances of less than 5 Mpc.

Cosmic expansion is manifested as an increasing recession velocity with distance; local contraction shows up as points of light, i.e. sources of radiant energy. In order to compare “apples to apples,” the rate-of-expansion must be converted to the rate-of-contraction. When you do this, you find that the rate-of-contraction is actually greater than the rate-of-expansion:

Rate of contraction (estimate post 33): = 2E-8 j/kg/s (2 x 10^(-8)).
Rate of expansion (estimate post 256): = 6E-9 j/kg/s

The first number represents the rate at which gravitational potential energy (GPE) is being converted to radiant energy. The second number represents the rate at which radiant energy is converted back into gravitational potential energy (see here). The difference between the two numbers is the net rate at which GPE is being converted into radiant energy.

In a nutshell, the cosmos is contracting “faster” than it is expanding. That is, the energy released by contraction is more than enough to explain the expansion.

Unless you can show where the numbers are wrong

[Van Rijn]

--The universe is contracting at the rate of 1.0E-8 j/kg/s at distances of less than 5 Mpc.

What is your specific evidence that the universe contracts at scales less than 5 Mpc?

As I noted in another thread, gravity dominates at smaller scales. That is very different from what you are saying.

[absolutely]

You are on the right track. The Universe is expanding and gravity is contracting. Do the math and see. The point of gravitational equilibrium for our local cluster is about 5 Mpc. For our galaxy it is about 1 Mpc. For a typical star (like our sun) it is about 1 pc. It explains the dynamics of everything from globular clusters and galaxies up to super-clusters as a viscous fluid, no dark matter required. See the universe in a coffee cup indeed.

[Bjoern]

Hello again, Peter. I am still waiting for you to answer my questions in the thread "Dark energy Dark matter". I asked them on December 30rd - one week ago. Isn't there a policy here on BAUT that questions about ATM ideas should be answered within a week...?

What is Duality?

Duality is the observation that the universe is neither expanding nor contracting, but doing both at the same time, i.e. is contracting locally while expanding cosmically.

Why do you think one needs to make up a fancy term for something which has been known for about 80 years, and which has been studied theoretically for at least 20 years now? Which is perfectly well explained by General Relativity? (studying density fluctuations on a Big Bang background)

It is my contention that mainstream models do not incorporate duality,

I already corrected you on that. Why do you ignore that?

and if they did, it will be seen that the cosmic (Hubble) expansion is merely the flip-side of local contraction.

They do, and it is clearly seen that your claim is totally wrong.

local contraction shows up as points of light, i.e. sources of radiant energy.

What on earth does that have to do with contraction?

In order to compare “apples to apples,” the rate-of-expansion must be converted to the rate-of-contraction. When you do this, you find that the rate-of-contraction is actually greater than the rate-of-expansion:

Rate of contraction (estimate post 33): = 2E-8 j/kg/s (2 x 10^(-8)).
Rate of expansion (estimate post 256): = 6E-9 j/kg/s

Why don't you convert both to a relative rate of change per second? Would make much more sense!

The first number represents the rate at which gravitational potential energy (GPE) is being converted to radiant energy. The second number represents the rate at which radiant energy is converted back into gravitational potential energy (see here). The difference between the two numbers is the net rate at which GPE is being converted into radiant energy.

GPE? Oh, that again reminds me of the answers in the other posts I'm still waiting for... (see above)

In a nutshell, the cosmos is contracting “faster” than it is expanding. That is, the energy released by contraction is more than enough to explain the expansion.

How does contraction release energy, and why does expansion require energy?

[Bjoern]

It would be helpful if you provided links to the relevant posts themselves instead of only to the threads containing them...

Rate of contraction (estimate post 33): = 2E-8 j/kg/s (2 x 10^(-8)).

That post and that number are about the energy emitted in the form of radiation, not about a "rate of contraction". Additionally, in that post you said that this energy output powers the expansion, not the contraction.

Rate of expansion (estimate post 256): = 6E-9 j/kg/s

That post is about the power required to separate two large "clumps" (5 Mpc), not about a "rate of expansion".


Calling these numbers "rate of contraction/expansion" makes little sense - you yourself pointed out already that such rates are usually given in the unit 1/s (or something equivalent). If you converted the numbers above to that unit somehow, please tell me where I can find the relevant post.

The first number represents the rate at which gravitational potential energy (GPE) is being converted to radiant energy. The second number represents the rate at which radiant energy is converted back into gravitational potential energy (see here).

I don't see what the "rate of contraction" should have to do with "the rate at which GPE is being converted to radiant energy", and what "rate of expansion" should have to do with "rate at which radiant energy is converted into GPE", and what both have to do with the power required to separate two 5 Mpc large clumps of matter. And I didn't find anything clarifying about that in the thread you mention here. It is quite long, so I perhaps missed the relevant post; could you please tell me which you meant?

[Peter Wilson]

Why do you think one needs to make up a fancy term for something which has been known for about 80 years, and which has been studied theoretically for at least 20 years now?

My first request, Bjoern, is that you not rush to judgement. The mainstream has overlooked something; it would behoove you to slow down and take a look at what I'm suggesting has been overlooked.

… How does contraction release energy, and why does expansion require energy?

If you consider the simplest gravitational system—two bodies orbiting each other—the system does not change without the input or loss of energy. If the system contracts, it must somehow lose energy; if the system expands, it must somehow gain energy.

If you consider gravitational systems more complex that two bodies, one part of the system—generally—contracts (releases energy) while another part expands (gains energy). Consider a 3-body system: the earth; a low-earth satellite and the moon. The satellite spirals in, losing gravitational potential energy (GPE), which is radiated away as heat; the moon, on the other hand, spirals away, gaining GPE. Thus, one part of this 3-body system contracts, while the other part expands.

So to answer the first part: How does contraction release energy? It does so via electromagnetic radiation: that is, local GPE is radiated away. To answer the 2nd part: Why does expansion require energy? For the same reason going up stairs requires energy.

Why don't you convert both to a relative rate of change per second? Would make much more sense!

It does not matter which units are used. If 10 mph is faster than 7 mph, it will still be faster in m/s, or whatever units you use. The answer does not depend upon the units: the universe is contracting faster than it is expanding.

Rate of contraction (estimate post 33): = 2E-8 j/kg/s (2 x 10^(-8)).

That post and that number are about the energy emitted in the form of radiation, not about a "rate of contraction". Additionally, in that post you said that this energy output powers the expansion, not the contraction.

Associated with contraction is the release of energy. Thus, the rate of energy loss is equivalent to the rate of contraction. The satellite orbiting earth and losing GPE as it spirals in loses energy at the rate at which it radiates away GPE. The satellite’s orbit is contracting at the rate it is radiating away energy. Virtually all “local” gravitational systems behave this way: they contract at the rate at which they radiate away energy.

Rate of expansion (estimate post 256): = 6E-9 j/kg/s

That post is about the power required to separate two large "clumps" (5 Mpc), not about a "rate of expansion".


Calling these numbers "rate of contraction/expansion" makes little sense - you yourself pointed out already that such rates are usually given in the unit 1/s (or something equivalent). If you converted the numbers above to that unit somehow, please tell me where I can find the relevant post.

Expanding two bodies in orbit, at a given rate, is an approximation for expanding an infinite number of bodies, at the same rate. If you do the calculation on a per-body basis (i.e. per kilogram), the 2-body approximation is in the same ballpark as the infinite-body system.

I don't see what the "rate of contraction" should have to do with "the rate at which GPE is being converted to radiant energy", and what "rate of expansion" should have to do with "rate at which radiant energy is converted into GPE", and what both have to do with the power required to separate two 5 Mpc large clumps of matter. And I didn't find anything clarifying about that in the thread you mention here. It is quite long, so I perhaps missed the relevant post; could you please tell me which you meant?

When you do see it, it will all add up.

If you look around, starting with yourself, you will see every “local” entity is in orbit around a local center-of-gravity. Yet a body orbiting another body does nothing without input or output of energy (see above). Think about a cloud of gas, contracting to form a star. The cloud of gas is orbiting about a center of gravity. There is a gravitational force inward; there is a gas-pressure force acting outwards. These two forces are in perfect balance…except for the radiant losses. With every photon radiated away, the gas cloud loses a little energy, and contracts a little bit. Therefore, the cloud of gas contracts at the rate at which it radiates away energy.

[Peter Wilson]

You are on the right track. The Universe is expanding and gravity is contracting. Do the math and see. The point of gravitational equilibrium for our local cluster is about 5 Mpc. For our galaxy it is about 1 Mpc. For a typical star (like our sun) it is about 1.5 ly. It explains the dynamics of everything from globular clusters and galaxies up to super-clusters as a viscous fluid, no dark matter required. See the universe in a coffee cup indeed.

I don't knkow about the coffe cup...but, Thanks.

Thanks also to Bob Angstrom, who has posted elsewhere his clear understanding and LOUD support of duality.

[Bjoern]

My first request, Bjoern, is that you not rush to judgement. The mainstream has overlooked something; it would behoove you to slow down and take a look at what I'm suggesting has been overlooked.

I've already told you several times now that in the mainstream, it has been clear for decades that on smaller scales, there is contraction, not expansion. So what has the mainstream overlooked?

If you consider the simplest gravitational system—two bodies orbiting each other—the system does not change without the input or loss of energy.
If the system contracts, it must somehow lose energy; if the system expands, it must somehow gain energy.

True for a circular orbiting system (for elliptical orbits, I think one could say that the system expands and contracts periodically). But consider an even simpler gravitational system: one body flying away from another. That system expands, and nevertheless its total energy stays the same. Hence you can't conclude that in general, expansion always implies gaining energy.

If you consider gravitational systems more complex that two bodies, one part of the system—generally—contracts (releases energy) while another part expands (gains energy).

Again: I wouldn't say that this is "generally" the case. Citing some examples does not prove that this happens generally.

As long as you haven't established that this is a general phenomenon (and I already gave a counterexample showing that this is indeed not general), your whole idea stands on rather shaky grounds. Hence I'll not respond to your further comments lower down in the same vein.

So to answer the first part: How does contraction release energy? It does so via electromagnetic radiation: that is, local GPE is radiated away. To answer the 2nd part: Why does expansion require energy? For the same reason going up stairs requires energy.

And yet again, radiating away GPE in the form of electromagnetic radiation happens only in some cases. You have not established that this is a general phenomenon. For example, in the case of the famous double pulsars, energy is emitted in the for of gravitational waves - not electromagnetic radiation.

It does not matter which units are used.

For a comparison, that obviously does not matter. But it would be far more intuitive expressed in that way.

If 10 mph is faster than 7 mph, it will still be faster in m/s, or whatever units you use. The answer does not depend upon the units: the universe is contracting faster than it is expanding.

But both of your calculations, for the expansion as well as for the contraction rate, were based on some simplifying (in some cases rather crude) assumptions. Hence the results are only (crude) approximations - and hence you can't use these numbers for claiming that one rate is bigger than the other. Doing a more accurate calculation could show that the opposite is true!

[Peter Wilson]

Rather, expansion is observable at larger scales, gravity dominates at smaller scales. There isn't a "5 Mpc" line in the sand, and expansion as well as gravitational force are accounted for...

Then what is the "expansion" force, if it is accounted for?

Did someone solve the Dark Energy problem, and I missed it?

No. An ad-hoc explosion was originally hypothesized to explain the expansion; this conjecture met with the horizon and flatness problems, so another ad-hoc conjecture--Infaltion--was added; this conjecture met with the acceleration problem, so a 3rd ad-hoc conjecture was added: Dark Energy. According to the mainstream, its ad-hoc conjectures all the way down.

Duality as an explanation, on the other hand, makes no conjectures or suppositions. It starts with one observation--all gravitational systems exhibit duality--and follows this observation to its logical conclusion: If every local region in the universe is contracting, then every non-local region be expanding. And this is exactly what we see.

Duality does not "guess" that there was a big explosion long ago.
Duality does not "guess" that there was "Inflation" long ago.
Duality does not "guess" that there is unseen Dark Energy today.
Duality does not "guess" that the speed of light is changing.
Duality does not "guess" that the gravitational "constant" is changing.

Duality observes, reasons, and concludes: The universe is contracting; the universe is expanding; the contraction releases more energy taken up by the expansion, ergo, the contraction is causing the expansion.

There is the explanation, from beginning to end.

[Peter Wilson]

I've already told you several times now that in the mainstream, it has been clear for decades that on smaller scales, there is contraction, not expansion. So what has the mainstream overlooked?

Sure, everybody knows clouds of gas contract to form stars, and galaxies collide, etc, but where is this local-contraction in the mainstream expansion model? I've already pointed you to one mainstream source that includes only one distance-scale, and no energy input from local contraction. "It" has been clear for decades, but "it" is missing from the mainstream model.

True for a circular orbiting system (for elliptical orbits, I think one could say that the system expands and contracts periodically). But consider an even simpler gravitational system: one body flying away from another. That system expands, and nevertheless its total energy stays the same. Hence you can't conclude that in general, expansion always implies gaining energy.

As you suggest, kinetic-plus-potential energy is constant; this is true for elliptical orbits and unbound bodies. My point is that the kinetic-plus-potential energy changes at the rate at which radiation carries off energy.

Consider the rings around Saturn and an accretion disk around a black hole. The rings of Saturn are quasi-stable, because they have no way to lose energy. The gas around a BH, however, reaches "billions-and-billions" of degrees, and because it is hot, it radiates away energy. Hence, the material around BHs spirals inwards (contracts) because--and only because--it is radiating away energy.

Again: I wouldn't say that this is "generally" the case. Citing some examples does not prove that this happens generally.

Right. I can give a few examples of animals that have sex. This does not prove that animals in general reproduce by having sex. But it is still true. And it is still true that in general, gravitational systems do not contract, except in proportion to the amount of energy they radiate away.

And yet again, radiating away GPE in the form of electromagnetic radiation happens only in some cases. You have not established that this is a general phenomenon. For example, in the case of the famous double pulsars, energy is emitted in the for of gravitational waves - not electromagnetic radiation...

Ok.
But it is still true that in general, gravitational systems do not contract, except in proportion to the amount of energy they radiate away...whatever form that radiation may take.

For a comparison, (the units used) obviously does not matter. But it would be far more intuitive expressed in that way.

Since we see stars radiating so-much energy per second, I feel this is the most intuitive way to express it. Evidently, you feel different.

But both of your calculations, for the expansion as well as for the contraction rate, were based on some simplifying (in some cases rather crude) assumptions. Hence the results are only (crude) approximations...Doing a more accurate calculation could show that the opposite is true!

Finally! Something we agree on

You are absolutely right: my estimates could be wrong.

But is it really my job to show it?

[Amber Robot]

An ad-hoc explosion was originally hypothesized to explain the expansion;

This ad hoc explanation also made predictions that agree with observations.

[nutant gene 71]

The raison d'être for the BA part of BAUT is to shoot-down astronomical misconceptions. I have put a concept on the table—duality—that purports to explain the expansion of the universe, and it remains undebunked...at least in my estimation

While mistakes were made in the original exposition, all but one were immediately caught by the readers, and all but one were immediately acknowledged and corrected by author…call the score even. Since all reported errors have been rectified, the conception/misconception sits in limbo. You can help decide the proposition.

What is Duality?

Duality is the observation that the universe is neither expanding nor contracting, but doing both at the same time, i.e. is contracting locally while expanding cosmically. It is my contention that mainstream models do not incorporate duality, and if they did, it will be seen that the cosmic (Hubble) expansion is merely the flip-side of local contraction.

Perhaps part of the difficulty is the fact that contraction and expansion manifest in different ways, and it is not at all immediately obvious that they are related.

--The universe is expanding at the rate of 2.3E-18/s (72 km/s/Mpc) at distances of greater than 5 Mpc,
--The universe is contracting at the rate of 1.0E-8 j/kg/s at distances of less than 5 Mpc.

Cosmic expansion is manifested as an increasing recession velocity with distance; local contraction shows up as points of light, i.e. sources of radiant energy. In order to compare “apples to apples,” the rate-of-expansion must be converted to the rate-of-contraction. When you do this, you find that the rate-of-contraction is actually greater than the rate-of-expansion:

Rate of contraction (estimate post 33): = 2E-8 j/kg/s (2 x 10^(-8)).
Rate of expansion (estimate post 256): = 6E-9 j/kg/s

The first number represents the rate at which gravitational potential energy (GPE) is being converted to radiant energy. The second number represents the rate at which radiant energy is converted back into gravitational potential energy (see here). The difference between the two numbers is the net rate at which GPE is being converted into radiant energy.

In a nutshell, the cosmos is contracting “faster” than it is expanding. That is, the energy released by contraction is more than enough to explain the expansion.

Unless you can show where the numbers are wrong

I must admit that I cannot understand ‘duality’ as here hypothesized, where something can be and not be at the same time. Either the universe is ‘homogenous and isotropic’ and it is expanding, or it is not. However, this hypothesized expansion of space is a function of our astronomical observations, that it ‘appears’ to be expanding at progressively larger distances, even appearing to be accelerating, if I understand it correctly, that at very great distances expansion is slower than for shorter distances. At the local level, no such expansion can be verified, now understood as a function of gravitational forces holding intra-galaxy matter together, so it may be contracting, but something that is not evident for inter-galaxies space, where they appear to be expanding. I wrote on the preceding thread (pre-split) something I think applies here as well:

I think this is the conundrum we encounter in Astronomy, versus all other science, in that our ‘tests’ for astronomical scientific theories are always at a distance, sometimes very great distances, so we do not have the benefit of falsifiable tests up close. How do we measure the speed of light, for example, in vicinity of our nearest stellar neighbors, such as Alpha Centaury? Or how do we know that implied Dark Energy, that which explains space expansion, exists at all? If we assume Doppler space expansion, something we cannot test for here on Earth, then the whole web of knowledge, even mathematically quantifiable knowledge, is only within the parameters of the logic constructed around this assumption. (Einstein assumed a homogenous and isotropic universe, but this is merely an assumption and not testable at present; in fact, we hope this is right to make it all fit mathematically!) But have we found other evidence to collaborate this logic? Is there evidence, for example, of space expansion tangentially? We only know of space expansion via ‘line of sight’, what we see in our instruments delving progressively deeper into space, and there the logic holds. But we cannot falsifiably test for it in any other way, except within the parameters of the web of mathematics we created to explain (assumed) Doppler space expansion. Is there any evidence of space expanding on Earth? No. So without such a collateral test, we are forced to fall back upon the logical explanations based upon our assumptions. But what if cosmic light redshifts for some other reason, perhaps something not yet considered (not counting tired light here), which would explain this redshift from another cause so that our observations of redshifts, consistent that they are for all distance as calculated, are actually no more than an optical illusion? Good science demands that we know the answer to this with some degree of falsifiable tests, and not merely accept that the logical calculations all work, so it must be right.

If the universe is indeed homogenous and isotropic, there should be some evidence of expansion locally, but there seems to be none, only gravitational effects holding our immediate vicinity of space as static. This is also not evident at the Quantum level, where no such expansion of space is evident. And since we cannot test for this expansion hypothesis tangentially, we are left with only the ‘line of sight’ evidence, due to redshifted light, that there is expansion at very great distances from our galaxy. Since we are unable to go in situ beyond our galaxy (we are barely able to send probes beyond our solar system), then we have no way to verify that such expansion is in fact real, and not merely an observational illusion. But if illusionary as an artifact of what our instruments register, then what happens to the Hubble constant? Is it illusory too? No math here, just some common sense reason. The alternative hypothesis, therefore and by default, is that our observed light redshift from great distances, as opposed to near our solar system, is that it may be due to other causes, as yet unknown (perhaps gravitationally driven), which means that in deep inter-galactic space something is different from what we know here. If so, then it necessitates entertaining at least the possibility that the universe is not ‘homogenous and isotropic’ as now postulated, or at least not the same matter, sans ‘dark matter/dark energy’, whereby the universe is homogenous and isotropic differently for out there versus in here. (I can produce the math to show how this is so, but it would be OT for this thread, not to mention highly speculative at this point.) Until we can find evidence that gravity acts differently for beyond the galaxy, viz. MOND like, than for within the solar system, we have no empirical evidence with which to support the math. So, thus it rests: a duality in our thinking, though not necessarily a duality in the way the universe works. In fact, it may all be very well unified with a better cosmological theory than GR/BBT type hypothesis, for example, where the variability of G for inner regions of space versus those very distant are explained by a new theory of the physics of gravity. Just a thought.

That said, I do find Peter Wilson’s hypothesis, that ” Duality is the observation that the universe is neither expanding nor contracting, but doing both at the same time, i.e. is contracting locally while expanding cosmically. It is my contention that mainstream models do not incorporate duality, and if they did, it will be seen that the cosmic (Hubble) expansion is merely the flip-side of local contraction,” intriguing. However, this necessitates some physics mechanism to explain how ” The first number represents the rate at which gravitational potential energy (GPE) is being converted to radiant energy. The second number represents the rate at which radiant energy is converted back into gravitational potential energy (see here). I am unfamiliar with such a thesis, where ‘gravitational potential’ and ’radiant energy’ are interactive as described. Indeed, the cosmological redshift is a ‘can of worms’ as said here. What happens to the Hubble constant if there is no Doppler expansion, but merely illusional, for example? Nixed?

[Bjoern]

Then what is the "expansion" force, if it is accounted for?

Who ever said expansion requires a force?

Did someone solve the Dark Energy problem, and I missed it?

What do you mean? That we don't know yet what it is?

No. An ad-hoc explosion was originally hypothesized to explain the expansion;

Would be news to me that the reasoning went like that. Please provide a quote from the inventors of the Big Bang theory saying that (hint: modern popular science descriptions don't count).

In fact, what happened was that it was observed that space expands, and this was extrapolated back. The obvious result was that there was a time when the density, temperature etc. were infinitely large, and the universe expanded and cooled down from that state. Calling this an "explosion" is, as far as I know, not found anywhere in actual scientific articles - only in dumbed down popular science descriptions.

this conjecture met with the horizon and flatness problems, so another ad-hoc conjecture--Infaltion--was added;

I don't know much about inflation or the reasons why it was used - hence I grant you that point.

this conjecture met with the acceleration problem, so a 3rd ad-hoc conjecture was added: Dark Energy.

The cosmological constant is a natural parameter in the equations of GR (and hence the BBT). It was not added ad hoc - it was simply determined by observations that its value is not zero (as was assumed for decades - for simplicity, and because no observations were available saying otherwise).

According to the mainstream, its ad-hoc conjectures all the way down.

May I ask you if you ever read a textbook on the BBT, or if you have all your information on it from popular science sources?

Duality as an explanation, on the other hand, makes no conjectures or suppositions. It starts with one observation--all gravitational systems exhibit duality--

I already presented a counterexample.

and follows this observation to its logical conclusion: If every local region in the universe is contracting, then every non-local region be expanding. And this is exactly what we see.

And how does this explain why the expansion is accelerating?

Additionally: can you make any quantitative descriptions of the expansion based on this idea and address the available data?

Duality does not "guess" that there was a big explosion long ago.

And neither the BBT. See above.

Duality does not "guess" that there was "Inflation" long ago.

The BBT did in a sense "guess" that, but then went on to look for evidence for this "guess" - or more properly said, hypothesis (hint: that's how science is done in general). And some evidence has already been found.

Duality does not "guess" that there is unseen Dark Energy today.

Again not a guess - but the observational determination of the value of a natural parameter of the theory.

Duality does not "guess" that the speed of light is changing.

And neither the BBT. Who said ever otherwise?

Duality does not "guess" that the gravitational "constant" is changing.

And neither the BBT. Who said ever otherwise?

Duality observes, reasons, and concludes: The universe is contracting; the universe is expanding; the contraction releases more energy taken up by the expansion, ergo, the contraction is causing the expansion.

Nice story. And now please address the actual data based on this idea. I. e., present something quantitative.

There is the explanation, from beginning to end.

A qualitative story is not an explanation.

[Bjoern]

Either the universe is ‘homogenous and isotropic’ and it is expanding, or it is not.

No, that's a false dichotomy. The universe is homogeneous and isotropic on large scales - and hence on large scales, there is expansion. On small scales, there obviously is lots of inhomogenity - and we see no expansion there, but contraction (in a sense). Matches quite well.

Since we are unable to go in situ beyond our galaxy (we are barely able to send probes beyond our solar system), then we have no way to verify that such expansion is in fact real, and not merely an observational illusion.

Why do you think that checking the predictions of the BBT against the observations is not a way to verify it?

If you can come up with a way how an "observational illusion" can explain all the evidence available for expansion (not only redshift, but also the time dilation in SN brightness curves, changing temperature of the CMBR, Tolman tests, simulations of large-scale structure formation agreeing with what is observed today etc.), feel free to present it.

The alternative hypothesis, therefore and by default, is that our observed light redshift from great distances, as opposed to near our solar system, is that it may be due to other causes, as yet unknown (perhaps gravitationally driven), which means that in deep inter-galactic space something is different from what we know here.

Again: feel free to come up with an explanation, based on this idea, which matches all the available evidence. See above.

If so, then it necessitates entertaining at least the possibility that the universe is not ‘homogenous and isotropic’ as now postulated,

Err, it is observed that the universe is homogeneous on large scales - not simply postulated (any more).
See e. g. here:
http://www.talkorigins.org/faqs/astr...ml#homogeneity

(I can produce the math to show how this is so, but it would be OT for this thread, not to mention highly speculative at this point.) Until we can find evidence that gravity acts differently for beyond the galaxy, viz. MOND like, than for within the solar system, we have no empirical evidence with which to support the math.

MOND is in trouble.
http://cosmicvariance.com/2006/08/21...matter-exists/

That said, I do find Peter Wilson’s hypothesis, that ” Duality is the observation that the universe is neither expanding nor contracting, but doing both at the same time, i.e. is contracting locally while expanding cosmically. It is my contention that mainstream models do not incorporate duality, and if they did, it will be seen that the cosmic (Hubble) expansion is merely the flip-side of local contraction,” intriguing.

Unfortunately for Mr. Wilson, mainstream models do incorporate both cosmological expansion and local contraction (and have done so for decades).
He continues to ignore that.

What happens to the Hubble constant if there is no Doppler expansion, but merely illusional, for example?

The cosmological redshift isn't attributed to a Doppler effect by cosmologists usually.
http://www.astronomycafe.net/cosm/expan.html

[Amber Robot]

In fact, what happened was that it was observed that space expands

Actually what was observed was a redshift-distance correlation. This has been explained, theoretically, by an expansion of space.

[Bjoern]

Sure, everybody knows clouds of gas contract to form stars, and galaxies collide, etc, but where is this local-contraction in the mainstream expansion model?

Look up "simulations of large-scale structure formation". These are based on an expanding universe (using BB math), but nevertheless describe local collapses of matter quite accurately. BTW, I already told you that, IIRC.

Since these simulations are rather complicated (essentially, one is doing numerical perturbation theory using big computers), you won't find this stuff mentioned in most popular science accounts of the BBT. You have to dig a bit deeper - but it is there nonetheless.

Try e. g. this article, for starters:
http://arxiv.org/pdf/astro-ph/0504097

I've already pointed you to one mainstream source that includes only one distance-scale, and no energy input from local contraction.

I don't remember you pointing me to such a source. Could you please provide the link again?

The gas around a BH, however, reaches "billions-and-billions" of degrees, and because it is hot, it radiates away energy. Hence, the material around BHs spirals inwards (contracts) because--and only because--it is radiating away energy.

You have it the wrong way round here. The gas heats up (and hence emits radiation) only because it spirals inwards. So the spiralling inwards is the cause of the radiation, not vice versa.

And it is still true that in general, gravitational systems do not contract, except in proportion to the amount of energy they radiate away.

Again, obviously right. So do you propose that only some systems are contracting, not all (could you give a proportion?), and the energy emitted by these some systems is already enough to cause the cosmological expansion? Or what?

Since we see stars radiating so-much energy per second, I feel this is the most intuitive way to express it. Evidently, you feel different.

For giving the amout of radiation emitted by stars, your units make sense. But you called your number the "rate of expansion". For such a rate, your units are awkward.

You are absolutely right: my estimates could be wrong.

But is it really my job to show it?

If you want to claim that your idea of duality can explain the expansion, obviously it is your job that this is indeed the case, and your result isn't just based on some rather crude approximations, which easily could be wrong! Who makes a claim, has to support it.

[Bjoern]

Actually what was observed was a redshift-distance correlation. This has been explained, theoretically, by an expansion of space.

Point granted. But one should also take into account that already several years previous to the redshift-distance correlation observation, Einstein predicted theoretically that space can expand (or contract). Hence I think one could also say that the redshift observation was essentially an observation that space expands.

[Amber Robot]

Hence I think one could also say that the redshift observation was essentially an observation that space expands.

Perhaps... I just think it is healthy for scientists to keep themselves intellectually honest by remembering what things are observations and what are theories.

[nutant gene 71]

No, that's a false dichotomy. The universe is homogeneous and isotropic on large scales - and hence on large scales, there is expansion. On small scales, there obviously is lots of inhomogenity - and we see no expansion there, but contraction (in a sense). Matches quite well.

Indeed, there is a difference in our observations of 'large scale vs. small scale', which is part of the conundrum.

Why do you think that checking the predictions of the BBT against the observations is not a way to verify it?

Independent verification is needed to falsifiably test our 'line of sight' observations. GR fits BBT, so it is acceptable in today's cosmology, but it is NOT a final test, IMO.

If you can come up with a way how an "observational illusion" can explain all the evidence available for expansion (not only redshift, but also the time dilation in SN brightness curves, changing temperature of the CMBR, Tolman tests, simulations of large-scale structure formation agreeing with what is observed today etc.), feel free to present it.

Then there's the Pioneer Anomaly, anomalous Titan's large atmosphere, flat rotation curves for outer galaxy, etc. We need better comprehensive theories, again IMO.

Again: feel free to come up with an explanation, based on this idea, which matches all the available evidence. See above.

I explored these ideas in various threads, some of the MOND math is here, and a whole thread discussing variable mass per variable G here, among others, like Jerry's ATM thread, and more. Lots of ATM questions, not fully explained.

Err, it is observed that the universe is homogeneous on large scales - not simply postulated (any more).
See e. g. here:
http://www.talkorigins.org/faqs/astr...ml#homogeneity

MOND is in trouble.
http://cosmicvariance.com/2006/08/21...matter-exists/
...
The cosmological redshift isn't attributed to a Doppler effect by cosmologists usually.
http://www.astronomycafe.net/cosm/expan.html

Thanks for the referenced links, lots to read up on, Bjoern. I agree with Galaxy Redshifts Reconsidered and Dark Matter Exists, though at this time not fully convinced that our homogenous/isotropic universe is not at higher Newton's (universal constant?) G for ordinary non-luminous baryonic matter, hence 'dark matter'.

[snip]

[Bjoern]

Perhaps... I just think it is healthy for scientists to keep themselves intellectually honest by remembering what things are observations and what are theories.

Well, I am a theoretical physicist, so I tend to talk more about theories than about observations.

[Amber Robot]

Well, I am a theoretical physicist, so I tend to talk more about theories than about observations.

And as a theoretical physicist, you should know the difference.