Origin of the Universe,,,,Bang or no Bang

[coldcreation]

In fact, galactic rotation curves leave 2 possibilities: GR is wrong, there is unaccounted-for mass.

 

The only way to make galactic rotation curves agree with General Relativity is to add mass because GR itself cannot be tweaked—it cannot be adjusted. This is something you often disagree with for one reason or another, but it isn't open to interpretation. GR is exactly demanding.

 

Indeed, this situation seems to require the introduction of non-baryonic matter (a hypothetical form of matter not made of electrons, protons, neutrons, quarks, etc.). It is a well-known that much of the mass in the universe is invisible to our telescopes. Planets, rocks, asteroids, brown dwarfs, often called “massive astrophysical compact halo objects” (MACHOS), objects with very little (or no) surface luminosity. But these objects may be insufficient to appease the necessary constraints.

 

Only 20% of the dark matter in our galaxy is in the form of MACHOs.

 

True, then, there appears to be an additional budgetary problem, but I wouldn't count on something nonbaryonic until it can be demonstrably tested experimentally that such a bizarre form of material exists. As you know, I argue that there is no such thing. Like eather of the 19th century, I suppose we'll have to live with it for a while, until an alternative quantitative solution (aside from MOND) emerges that does away with the untenable concept. (There already exists a qualitative scenario :)).

 

Perhaps there will be found a way to adjusted GR (with a slight modification) in such a way that allows for the observed curves without revamping the entire postulate.

 

It seems logical that such an analytical solution should be sought, rather than accepting unilaterally the ethereal, the dark, without palpable empirical evidence.

 

 

...The same theory that predicts gravitational effects in our solar system to extraordinary precision also predicts the behavior of the FLRW metric (i.e. a Friedmann universe). Any observation of a homogeneous, isotropic universe that obeys the physics of General Relativity *must* agree with the FLRW metric or General Relativity is proven wrong by example. There is no leeway on this.

 

The difference is that there is no need for CDM or DE within solar system dynamics (GR works). The same cannot be said of a Friedmann universe, where GR needs to be supplemented liberally.

 

That doesn't mean GR is wrong. It could simply be that the FLRW metric is not the metric of choice when it comes to describing the universe. If the latter is the case, then there is your leeway.

 

 

Our cosmic observations do indeed agree with the FLRW metric if the makeup of the universe is currently 74% vacuum energy density and 26% mass density as a ratio to the critical density. Either this is not the makeup of our universe, the universe is not homogeneous and isotropic, or FLRW and by extension GR are wrong.

 

It would have been a beautiful result had cosmic observations agreed with the FLRW metric without 74% vacuum energy and 26% nonbaryonic cold dark mass density.

 

 

Now the beauty is nowhere to be found.

 

 

 

The only Leeway FLRW affords is setting the values (the Omegas) which is the same as declaring what our universe is made of. That's it.

 

I know you feel DE and CDM follow naturally from GR or FLRW, but believe me, there is nothing natural about it.

 

Dangit them SNe Type Ia.

 

 

You seem to be confusing the setting, measuring, and changing of these parameters with a change to the underlying physics.

 

Underlying physics has to change.

 

High-energy physicists have proposed various candidates for non-baryonic dark matter' date=' all of which would indicate new physics beyond the well tested Standard Model of particle physics. [...']

 

Another candidate for non-baryonic dark matter is the family of heavier neutral particles known as weakly interacting massive particles or WIMPs. The leading candidate in this class is the neutralino, a particle predicted by the so-called supersymmetric (SUSY) extension to the Standard Model. [...]

 

Altogether there are now more than a dozen experiments searching for WIMPs, plus several experiments that are looking for axions - very light particles with masses in the range 10-4-10-6 eV c-2 that have been predicted to exist by several theories. Detection of a WIMP particle or an axion would clearly have a major impact on future directions in particle physics. Source: The search for dark matter

 

 

You can set Omega-M and Omega-Vac and get a prediction at a chosen redshift. Pre-1998 cosmology can be solved on this calculator as well as the current Lambda-CDM model, because they use *exactly* the same physics.

 

 

 

PS. Check this out. The world's first space resort in orbit by 2012, a good place to ponder the fate of the universe. It's not too late to make your reservations. :doh:

 

 

 

 

 

CC

[Pluto]

G'day Modest

 

I gave my friends the link for them to join.

 

I hope they do in a way, but than again they are BBT people.

 

Smile.

 

===============================

 

I thought the mass of 95% is found as compact matter through out the galaxy.

 

I could be wrong, I better check it, before someone tells me to back it up.

 

Eg Our Sun has 99% mass compared to the remaining solar system.

 

Yes I know that the sun is not all compact. But! The core is.

[modest]

I thought the mass of 95% is found as compact matter through out the galaxy.

 

I believe you're confusing a few different things. It's possible to roughly determine the mass of the Milky Way by measuring the velocity of stars and dwarf galaxies at the perimeter of our galaxy. Doing this shows a mass of at least 600 billion solar masses, and more-likely one trillion solar masses. (1)(2).

 

Only about 200 billion solar masses of that total mass is definitively accounted for as "visible" matter. That is a very rough estimate because there is a lot of uncertainty regarding the number of low-mass stars. But, it's generally agreed that there is some form of hidden or invisible mass which is (at this point) only detectable through its gravitational effects.

 

That hidden matter goes by the name dark matter. The term "dark" refers to our inability to see it which mostly reflects our ignorance regarding what exactly it is. The search is on and some dark matter candidates have been convincingly ruled out.

 

Where you say "95% is found as compact matter", I believe you are recalling the dark matter candidate MACHOs (massive astrophysical compact halo object). It is NOT the same thing as degenerate matter (which you often call compact matter). MACHOs are planet-sized or star-sized chunks of normal matter which do not emit much (if any) light. These might include black holes, neutron stars, white dwarfs, or red dwarfs.

 

Studies have shown that MACHOs are not likely to account for large amounts of dark matter. Astrophysicist seem more-convinced that dark matter consists of fundamental non-baryonic (non-relativistic) particles. You can think of these as invisible subatomic particles floating around everywhere, but they are invisible and don't interact with normal baryonic matter (the stuff you and I are made of). This cold dark matter is NOT the same thing as degenerate matter (or compact matter).

 

The current big bang theory proposes that there is five and a half times as much cold dark matter as there is normal visible matter. This could be consistent with the missing mass in galaxies. I believe the number you gave of 95% was meant to be 96% which is the proposed percentage of the universe's energy density which is not normal visible matter. However, only 22% is cold dark matter. The other 74% is dark energy which is a whole different subject (again—*not* degenerate or compact matter).

 

So, I think your quote above probably meant to say that 96% of our universe (not galaxy) is dark matter and dark energy—which I would agree, that is the current model which cosmologists use to describe our universe. But, as Coldcreation said, those numbers represent something we believe is there, but we know very little about.

 

Eg Our Sun has 99% mass compared to the remaining solar system.

 

I believe strongly that you're confusing the sun (which is normal baryonic matter like you and I are made of) with degenerate matter (such as you would find in a neutron star) and dark matter / dark energy (neither of which make up stars).

 

Yes I know that the sun is not all compact. But! The core is.

 

Yes, when the sun runs out of stuff to fuse then thermal pressure will give way to degenerate pressure and it will collapse into a white dwarf composed of "degenerate matter" and considered a "compact object". You can read about the sun's core in its current condition in this article:

Solar core - Wikipedia, the free encyclopedia

It is not currently degenerate matter but that is very far off the topic of cold dark matter.

 

~modest

[modest]

Indeed, this situation seems to require the introduction of non-baryonic matter (a hypothetical form of matter not made of electrons, protons, neutrons, quarks, etc.). It is a well-known that much of the mass in the universe is invisible to our telescopes. Planets, rocks, asteroids, brown dwarfs, often called “massive astrophysical compact halo objects” (MACHOS), objects with very little (or no) surface luminosity. But these objects may be insufficient to appease the necessary constraints.

 

Only 20% of the dark matter in our galaxy is in the form of MACHOs.

 

True, then, there appears to be an additional budgetary problem, but I wouldn't count on something nonbaryonic until it can be demonstrably tested experimentally that such a bizarre form of material exists. As you know, I argue that there is no such thing. Like eather of the 19th century, I suppose we'll have to live with it for a while, until an alternative quantitative solution (aside from MOND) emerges that does away with the untenable concept. (There already exists a qualitative scenario :shrug:).

 

Well said. I don't see this as an unreasonable position. Non-baryonic dark matter is not an easy pill to swallow. It seems, though, more and more evidence is coming in that is consistent with non-baryonic and cold dark matter—like dark matter gravitational lensing. Meanwhile, more and more candidates for baryonic dark matter are ruled out as telescopes get better at looking for them.

 

The indirect evidence is speaking pretty loudly.

 

The difference is that there is no need for CDM or DE within solar system dynamics (GR works). The same cannot be said of a Friedmann universe, where GR needs to be supplemented liberally.

 

Well, I would prefer GR work at all scales. As far as the solar system goes, I don't think the presence of dark energy or dark matter would really change the motion of the planets.

 

The cosmological constant part of gravity (dark energy) increases linearly with distance while the term responsible for gravitational attraction decreases quadratically.

[math]\text{Gravitational Force}=-\frac{GM}{r^2}+\frac{c^2{\Lambda}r}{3}[/math]

This means there is virtually no contribution from the cosmological constant over small distances. The second term above is very nearly zero with a small r (r is distance). Over larger and larger distances the cosmological constant becomes a larger and larger factor. As r increases the first term above tends toward zero while the second becomes increasingly larger. So, dark energy which has a very noticeable effect on the evolution of the universe may have no noticeable effect on the motion of the planets. The following paper comes to that conclusion doing all the proper calculations:

In this note we have discussed the possibility of constraining the cosmological constant [math]\Lambda[/math], in a general relativistic framework, with Solar System observations in view of the latest results in planetary orbit determinations. Contrary to what claimed by some authors, it turns out that it is not possible to get useful bounds on [math]\Lambda[/math] from such local scale tests.

 

http://arxiv.org/PS_cache/gr-qc/pdf/0602/0602095v2.pdf

 

Also, non-baryonic CDM might not show up as gravitational effects in the solar system. Dark matter doesn't interact with ordinary matter so it wouldn't necessarily clump together with normal matter on scales so small. Dark matter would only affect the orbit of the planets if the concentration of dark matter in our solar system was greater than the concentration in the background of the galaxy. And, that is not the case:

In this paper we have worked out the effects that a local excess of dark matter in our Solar System over the galactic background would induce on the orbits of the planets... The comparison with the latest data show that the upper bounds obtainable from the mean longitudes and the perihelia are of the order of 10^−20 g cm−3 and 10^−19 g cm−3, respectively.

 

http://arxiv.org/PS_cache/gr-qc/pdf/0602/0602095v2.pdf

 

So, General Relativity can be consistent with our observations in the solar system as well as galactic and cosmic observations if dark matter and dark energy do indeed exist. If they do *not* exist then we would expect solar system observations to be the same, but galactic and cosmic observations would be somewhat different that we have observed.

 

That doesn't mean GR is wrong. It could simply be that the FLRW metric is not the metric of choice when it comes to describing the universe. If the latter is the case, then there is our leeway.

 

But, there can't be two solutions describing the same physical situation that give two different answers. That would be like solving GR and finding the surface gravity on earth should be g and solving it a different way and finding the surface gravity should be twice g. As far as I know, General Relativity (including any exact solutions to GR) give exact answers. I don't think we can just find a new metric, or try to solve GR differently.

 

A great example of this are the first two models of cosmology based on GR—that of de Sitter and Einstein himself. Einstein's metric had matter, was spatially closed, and had a cosmological constant. De Sitter's had no matter or radiation pressure, was spatially open, and had a cosmological constant. These two metrics described two very different situations, but the later development of Friedmann's metric (FLRW) could include both situations. In fact, it was shown that Einstein's and de Sitter's universe were two examples of a family of universes described by FLRW. It is now generally accepted that our universe is turning into a de Sitter universe as described by wiki here:

Because our Universe has entered the Dark Energy Dominated Era a few billion years ago, our universe is probably approaching a de Sitter universe in the infinite future. If the current acceleration of our universe is due to a cosmological constant then as the universe continues to expand all of the matter and radiation will be diluted. Eventually there will be almost nothing left but the cosmological constant, and our universe will have become a de Sitter universe.

 

de Sitter universe - Wikipedia, the free encyclopedia

 

Such a universe can be described with the de Sitter metric or the FLRW metric. Where they describe the same thing, they are the same. So, I don't think it's a matter of finding a new metric.

 

It seems, at this point, we either need to accept dark energy and dark matter as plausible or we need to figure out what has gone wrong with our cosmic solutions to general relativity.

 

Also, let me be clear—we're talking about the finer points of a big bang model here. The integrity of "the big bang" (i.e. the primordial atom) is not IMHO in jeopardy. The evidence for a big bang persist even if ΛCDM ends up being completely broken. If a person uses math to model a car crash and the model ends up being wrong that doesn't mean the car crash didn't happen. The broken glass and skid marks and whatnot are evidence of the crash with or without the model.

 

~modest

[Pluto]

G'day from the land of ozzzzzz

 

I have been away for the last 2 days.

 

I have read modests response, and will come back to it in the next day or so.

[coldcreation]

Well said. I don't see this as an unreasonable position. Non-baryonic dark matter is not an easy pill to swallow.

 

It's funny, Lawrence Krauss is of the same opinion. After having written that he would be “very surprised if any of these initial models [GUTs or inflation] turned out to be true” (since both were divest of quantum gravity) he promptly then introduces the nonbaryonic dark matter issue to explain the flatness problem, saying the “stuff” must be made of “something else” as opposed to ordinary matter, and that we must have “missed most of it,” then concludes in his most expansive moment; “This is a very large pill to swallow.” (Krauss, 2001, pp. 138-68)

 

 

It seems, though, more and more evidence is coming in that is consistent with non-baryonic and cold dark matter—like dark matter gravitational lensing. Meanwhile, more and more candidates for baryonic dark matter are ruled out as telescopes get better at looking for them.

 

Eventually—and again, this is just an opinion or a prediction based on an alternative pet theory—all candidates for nonbaryonic cold dark matter should be ruled out. This at least is the hope, as our theoretical underpinnings of how nature works become more robust.

 

 

The indirect evidence is speaking pretty loudly.

 

True, but direct evidence leaves little to be desired.

 

 

Well, I would prefer GR work at all scales. As far as the solar system goes, I don't think the presence of dark energy or dark matter would really change the motion of the planets.

 

I would prefer GR work at cosmological scales without artificial contrivance, a voluntary Agent, a divine arm. The outlook is that in absence of a solid basis of experimental corroboration, a projected hypothesis is not on firm ground. In other words, modern cosmology has erected ‘new physics’ to fill the growing breach between theory and empirical evidence, direct or indirect.

 

 

So, General Relativity can be consistent with our observations in the solar system as well as galactic and cosmic observations if dark matter and dark energy do indeed exist...

 

Yes, and that seems to be the only way around the budgetary problem, without a full-scale revision of cosmology.

 

What counts (pun non-intended) is that physics must be verifiable, factual when possible and that it be utilized to make accurate interpretations.

 

Clearly there is a risk here. If physics is over-relaxed, or worse, vacated (extended beyond the empirically testable), the result inevitably leads towards something that is not physics, not natural, and ultimately less desirable, especially when the goal is to explain the physical world.

 

Tough standards, therefore, should be maintained (and imposed) to reduce the risk of cosmology running amok.

 

For now, few seem to believe that cosmology should stick to standard particle physics, despite the current low-credibility factor with respect to a mysterious cold dark matter dominating the cosmos.

 

This is another risk, yet perhaps worth taking: to place the field of cosmology back into the domain of testable physics. This policy might help reinvigorating a constructive debate over such important issues as the SNe Ia survey results.

 

 

But, there can't be two solutions describing the same physical situation that give two different answers. [...] As far as I know, General Relativity (including any exact solutions to GR) give exact answers. I don't think we can just find a new metric, or try to solve GR differently.

 

Einstein had written, 'It is the theory that decides what we can observe.'

 

There can be two interpretations (or solutions) describing the same observations that give two different answers. The solution depends on fundamental assumptions made at the outset.

 

Cosmology is a field where direct observations are made but the interpretation of those observations depend heavily on (in this case) a form a matter (CDM) currently beyond the limits of experimental verification and thus becomes more based on assumptions, a person's philosophy and/or religion. (See here for an interesting discussion: The Problem of Observation and Regional Ontologies).

 

Some interpretations are treated as if they were observations. These are 'commonsense' interpretations, such as "there's not enough visible mass to cause gravitational lensing, or a flat rotational curve, so there has to be something more: CDM." Here, there is an interpretation—though based on direct observations—presented as if it were the actual observation of CDM, and so the need to support the interpretation with direct evidence or explanation within the bounds of tested particle physics is vacated.

 

It gives the impression of solid evidence, though with an unstated presumption that a large body of underlying physics must be true, and simultaneously failing to consider opposing interpretations, because of uncritically accepted assumptions inherent within the standard model.

 

We should challenge the scientific community to offer alternative scenarios based on an underlying physics that has been tested, and challenge the untestable assumptions.

 

 

A great example of this are the first two models of cosmology based on GR—that of de Sitter and Einstein himself. Einstein's metric had matter, was spatially closed, and had a cosmological constant. De Sitter's had no matter or radiation pressure, was spatially open, and had a cosmological constant. These two metrics described two very different situations, but the later development of Friedmann's metric (FLRW) could include both situations. In fact, it was shown that Einstein's and de Sitter's universe were two examples of a family of universes described by FLRW. It is now generally accepted that our universe is turning into a de Sitter universe...

 

But just because something is generally accepted does not make it true.

 

It's ironic, too, that the original de Sitter world model was non-expanding and non-contracting (stationary).

 

Recall Edwin Hubble's words: “In the de Sitter cosmology, displacements of the spectra arise from two sources, an apparent slowing down of atomic vibrations and a general tendency of material particles to scatter. The latter involves an acceleration and hence introduces the element of time.” (Hubble 1929, A Relation Between Distance and Radial Velocity Among Extra-Galactic Nebula).

 

Though Hubble had slightly misinterpreted the de Sitter effect. The slowing down of clocks with distance is the element of time.

 

In the same works, Hubble wrote: “The outstanding feature, however, is the possibility that the velocity-distance relation may represent the de Sitter effect, and hence that numerical data may be introduced into discussions of the general curvature of space.”

 

The de Sitter universe was static, yet the light emitted by objects in it appeared redshifted (the infamous de Sitter effect).

 

 

Such a universe can be described with the de Sitter metric or the FLRW metric. Where they describe the same thing, they are the same. So, I don't think it's a matter of finding a new metric.

 

A de Sitter universe can either be interpreted as flat and expanding, or curved and stationary.

 

The observation is the same. The interpretation is different.

 

 

It seems, at this point, we either need to accept dark energy and dark matter as plausible or we need to figure out what has gone wrong with our cosmic solutions to general relativity.

 

Great point. More work arguably needs to be done on the latter.

 

 

Also, let me be clear—we're talking about the finer points of a big bang model here. The integrity of "the big bang" (i.e. the primordial atom) is not IMHO in jeopardy. The evidence for a big bang persist even if ΛCDM ends up being completely broken. If a person uses math to model a car crash and the model ends up being wrong that doesn't mean the car crash didn't happen. The broken glass and skid marks and whatnot are evidence of the crash with or without the model.

 

Actually, the primordial atom echoes the full pictorial inventiveness of Biblical creation (a useful parameterization of ignorance).

 

Truly, the primeval atom has left Himself without witness. Until physics can take us there (to t = 0) the primordial atom is in jeopardy.

 

The big bang itself, with its inaccessible tenants, has always carried with it a heightened vigilance against guided attacks; freed from the customary checks and balances of natural laws, physics, the ethical codes of science.

 

If Lambda-Cold Dark Matter ends up being completely broken, say, after more is learned about the applicable fundamental physics, or if next-generation telescopes show it to be untenable, then both the big bang theory and the shrouded primeval detonation (whatever is believed to have happened at t = 0) are in jeopardy.

 

To use your analogy above, the broken glass and skid-marks may not be evidence of a crash at all, within the framework of a model that would/should/could eventually replace ΛCDM.

 

The fundamental physical origin of matter (e.g., electrons, protons and neutrons), the physical interpretation of redshift z, the quasi-scale-invariant spectrum of CMBR curvature perturbations, the origin of the CMBR itself, large scale structure observations and SNe Ia data would all be subject to review.

 

 

 

 

CC

[modest]

It's funny, Lawrence Krauss is of the same opinion. After having written that he would be “very surprised if any of these initial models [GUTs or inflation] turned out to be true” (since both were divest of quantum gravity) he promptly then introduces the nonbaryonic dark matter issue to explain the flatness problem, saying the “stuff” must be made of “something else” as opposed to ordinary matter, and that we must have “missed most of it,” then concludes in his most expansive moment; “This is a very large pill to swallow.” (Krauss, 2001, pp. 138-68)

Uhhh... Great minds think alike....? :hihi:

 

It's ironic, too, that the original de Sitter world model was non-expanding and non-contracting (stationary).

 

Recall Edwin Hubble's words: “In the de Sitter cosmology, displacements of the spectra arise from two sources, an apparent slowing down of atomic vibrations and a general tendency of material particles to scatter. The latter involves an acceleration and hence introduces the element of time.” (Hubble 1929, A Relation Between Distance and Radial Velocity Among Extra-Galactic Nebula).

 

Though Hubble had slightly misinterpreted the de Sitter effect. The slowing down of clocks with distance is the element of time.

 

In the same works, Hubble wrote: “The outstanding feature, however, is the possibility that the velocity-distance relation may represent the de Sitter effect, and hence that numerical data may be introduced into discussions of the general curvature of space.”

 

The de Sitter universe was static, yet the light emitted by objects in it appeared redshifted (the infamous de Sitter effect). :)

 

A de Sitter universe can either be interpreted as flat and expanding, or curved and stationary.

 

The observation is the same. The interpretation is different.

 

I probably shouldn't have picked that scab :doh:

 

De Sitter's universe is static... sure. The thing is, if you put two stars in his universe separated by some distance, they will scatter. They will physically move apart in a way that is exactly described by FLRW with de Sitter parameters (zero mass and cosmological constant).

 

So, the repulsion (the expansion) is real in either metric. Milton Karl Munitz explains:

Allusion has been made to the fact that the recession of the galaxies in the present theory of the expanding universe is not precisely the effect forseen by de Sitter. It may be well to explain the manner of the transition. The phenomenon that is generally called the “de Sitter effect” was a rather mysterious slowing down of time at great distances from the observer; atomic vibrations would be executed more slowly, so that their light would be shifted to the red and imitate the effect of a receding velocity. But besides discovering this, de Sitter examined the equations of motion and noticed that the real velocities of distant objects would probably be large; he did not, however, expect these real velocities to favour recession rather than approach. I am not sure when it was first recognized that the complication in the equations of motion was neither more nor less than a repulsive force proportional to the distance; but it must have been before 1922. Summarizing the theory at that date, I wrote—“De Sitter’s theory gives a double explanation of this motion of recession: first, there is the general tendency to scatter according to the equation [math]d^2r/ds^2 = 1/2 \lambda r[/math]; second, there is the general displacement of spectral lines to the red in distant objects due to the slowing down of atomic vibrations which would be erroneously interpreted as motion of recession.” I also pointed out that it was a question of definition whether the later effect should be regarded as a spurious or a genuine velocity. During the time that its light is traveling to us, the nebula is being accelerated by the cosmcal repulsion and acquires an additional outward velocity exceeding the amount in dispute; so that the velocity, which was spurious at the time of emission of the light, has become genuine by the time of its arrival. Inferentially this meant that slowing down of time had become a very subsidiary effect compared with cosmical repulsion; but this was not so clearly realized as it might have been. The subsequent developments of Freedmann and Lemaitre were geometrical and did not allude to anything so crude as “force”; but, examining them to see what has happened, we find that slowing down of time has been swallowed up in the cosmical repulsion; it was a small portion of the whole effect (a second order term) which had been artificially detached by the earlier methods of analysis.

 

Theories of the Universe: From ... - Google Book Search

 

~modest

 

EDIT: **************

 

I'm sorry, I attributed the passage above to Milton Munitz. It comes from Munitz's book, but is written by Eddington.

 

In looking for a source to expand his "double explanation of this motion of recession" quote I found the following paper which I really enjoyed reading:

The Origins of the Velocity-Distance Relation JOURNAL FOR THE HISTORY OF ASTRONOMY V. 10, P. 133, 1979

It has a bit more of Eddington's quote:

One of the most perplexing problems of cosmogony is the great speed of the spiral nebulae. Their radial velocities average 600 km per second and there is a great preponderance of velocities of recession from the solar system. It is usually supposed that these are remote objects known (though the view is opposed by some authorities), so that here if anywhere we might look for effects due to a general curvature of the world [universe]. De Sitter’s theory gives a double explanation of this motion of recession; first, there is the general tendency to scatter... second, there is the general displacement of spectral lines to the red in distant objects due to the slowing down of atomic vibrations which... would be erroneously interpreted as the motion of recession.

 

-A.S. Eddington; The mathematical theory of relativity (1923)

 

The paper also discusses de Sitter's rejection of his own model in favor of Lemaitre's.

 

I also found an interesting 1929 paper by Tolman which relates de Sitter's model to astronomical findings:

http://adsabs.harvard.edu/full/1929ApJ....69..245T

[Pluto]

G'day from the land of ozzzzz

 

Great discussion by Modest and coldcreation.

 

===========================

 

Compact matter and degenerate matter.

 

Does matter need to become degenerate before compaction?

 

===========================

 

I'm reading through this topic, still on the search for the mechanism that originates all forms of jets small or large.

 

 

Tokamak

arXiv.org Search

 

 

 

Spherical Tokamak Plasma

arXiv.org Search

 

and it seems that the pinching of magnetic fields could be the trigger.

 

I feel that I'm years from the answer.

 

Unless someone here can help.

[modest]

Compact matter and degenerate matter.

 

Does matter need to become degenerate before compaction?

 

I don't know the difference between the two. As far as I can tell, "degenerate matter" is what you mean. When a star collapses and forms degenerate matter (such as a neutron star) then the star is often called a "compact object". My guess is that you've combined the terms "compact object" and "degenerate matter". But, I would avoid doing that. "Compact matter" is not a term that's usually used as far as I can tell. Degenerate is more descriptive and more-often used.

 

~modest

[Pluto]

G'day from the land of ozzzzz

 

Your right Modest.

 

I have used

 

Degenerate matter

Compact matter

Ultra dense matter

Ultra dense plasma matter

Compact objects

 

Some papers use these terms.

 

This is a good excuse to read up on some papers

Such as, this does not mean that you have to read them, just letting you know how I occupy my time.

 

arXiv.org Search

 

In due time I will understand the origins of jets and what triggers them.

 

I should have pick up tennis.

[Pluto]

G'day from the land of ozzzzzz

 

I came across this paper, it maybe of interest.

 

[0803.2509] Twisted coronal loops in uniform gravity

Twisted coronal loops in uniform gravity

 

Authors: G.J.D. Petrie

(Submitted on 17 Mar 2008)

 

Abstract: Coronal loop emission profiles are often of remarkably constant width along their entire lengths, contradicting expectations based on model coronal magnetic field strengths decreasing with height. Meanwhile Paul Bellan has produced a theoretical model in which an initially empty, twisted force-free loop, on being filled with plasma via upflow at each foot point, in the absence of significant gravitational effects, forms a narrow, filamentary loop of constant cross-section. In this paper, we focus on equilibrium states that include stratification by uniform gravity while retaining the effects of magnetic field twist. Comparing these with related force-free equilibria, it is found that injection of low-$beta $ plasma under coronal conditions is not likely to change the shape of a loop significantly. These linear equilibria apply to the interiors and boundaries of loops only, with external influences modeled by boundary total pressures. The effects of total pressure balance with surroundings and of gravitational stratification are to inhibit the pinching of a loop to a constant cross-section. Only if the plasma $beta$ were high enough for the plasma to reconfigure the external field and the hydrostatic scale height much greater than the loop size could the final state have nearly constant cross section. We do not expect this to occur in the corona.

 

and

 

[0802.2034] Extragalactic jets with helical magnetic fields: relativistic MHD simulations

Extragalactic jets with helical magnetic fields: relativistic MHD simulations

 

Authors: R. Keppens, Z. Meliani, B. van der Holst, F. Casse

(Submitted on 14 Feb 2008)

 

Abstract: Extragalactic jets are inferred to harbor dynamically important, organized magnetic fields which presumably aid in the collimation of the relativistic jet flows. We here explore by means of grid-adaptive, high resolution numerical simulations the morphology of AGN jets pervaded by helical field and flow topologies. We concentrate on morphological features of the bow shock and the jet beam behind the Mach disk, for various jet Lorentz factors and magnetic field helicities. We investigate the influence of helical magnetic fields on jet beam propagation in overdense external medium. We use the AMRVAC code, employing a novel hybrid block-based AMR strategy, to compute ideal plasma dynamics in special relativity. The helicity of the beam magnetic field is effectively transported down the beam, with compression zones in between diagonal internal cross-shocks showing stronger toroidal field regions. In comparison with equivalent low-relativistic jets which get surrounded by cocoons with vortical backflows filled by mainly toroidal field, the high speed jets demonstrate only localized, strong toroidal field zones within the backflow vortical structures. We find evidence for a more poloidal, straight field layer, compressed between jet beam and backflows. This layer decreases the destabilizing influence of the backflow on the jet beam. In all cases, the jet beam contains rich cross-shock patterns, across which part of the kinetic energy gets transferred. For the high speed reference jet considered here, significant jet deceleration only occurs beyond distances exceeding ${cal O}(100 R_j)$, as the axial flow can reaccelerate downstream to the internal cross-shocks. This reacceleration is magnetically aided, due to field compression across the internal shocks which pinch the flow.

 

 

Could this process be part of a recycling of matter from degenerate to normal matter?

[CraigD]

[0803.2509] Twisted coronal loops in uniform gravity

Twisted coronal loops in uniform gravity

 

Authors: G.J.D. Petrie

(Submitted on 17 Mar 2008)

 

and

 

[0802.2034] Extragalactic jets with helical magnetic fields: relativistic MHD simulations

Extragalactic jets with helical magnetic fields: relativistic MHD simulations

 

Authors: R. Keppens, Z. Meliani, B. van der Holst, F. Casse

(Submitted on 14 Feb 2008)

 

Could this process be part of a recycling of matter from degenerate to normal matter?

In short, based on the quoted text, no.

 

No reference is made in the quoted text to degenerate mater. All the reference and research literature of which I’m familiar, including all that quoted in this thread, explicitly or implicitly states that the jets and disks of various astronomical consist only of normal matter at densities much less than those of stellar cores, which are insufficiently compacted to undergo any form of degeneracy. Objects such as neutron stars, and possibly black holes, are strongly hypothesized to contain degenerate matter, but have no mechanism that can eject this matter.

 

Pluto, if you have any references contradicting this, please post them. Don’t continue posting quotes that don’t support your claim, then repeating the same claim in the form of a question. You can’t make sources that don’t support, and in many cases contradict, your claims, support them by providing many such sources. :)

[Pluto]

G'day from the land of ozzzzz

 

CraigD said:

 

In short, based on the quoted text, no.

 

Which quoted text?

 

We know that the progressive evolution of a stella black hole is via the formation of a Neutron core Star. This would imply that the matter found in the so called black hole is in some form of degenaracy.

 

We also know that by general information that the form that a galaxy takes is directly related to the size and activity of the central black hole. This also implies that the Black hole mass changes by some mechanism meaning that black holes can in release or lose mass.

 

After reading hundreds of papers from NASA ADS and arXiv there is seems to be no evidence either way to say that black holes cannot eject matter from the core. There is a question mark on the mechanism of how the jets form either from the core or from the disc or a combination of both.

 

Weak jets tend to form in turbulent areas while stable jets a formed by a strong stable origin possibly near or in the core of a black hole. If we treat the core as compact matter than we can apply physics to the area.

 

[0801.0617] The Trails of Superluminal Jet Components in 3C111

The Trails of Superluminal Jet Components in 3C111

 

Authors: M. Kadler (NASA GSFC and MPIfR), E. Ros (MPIfR), M. Perucho (MPIfR), Y. Y. Kovalev (MPIfR and ASC Lebedev), D. C. Homan (Denison U.), I. Agudo (CSIC and MPIfR), K. I. Kellermann (NRAO), M. F. Aller (U. Michigan), H. D. Aller (U. Michigan), M. L. Lister (Purdue U.), J. A. Zensus (MPIfR)

(Submitted on 4 Jan 2008 (v1), last revised 7 Jan 2008 (this version, v2))

 

Abstract: In 1996, a major radio flux-density outburst occured in the broad-line radio galaxy 3C111. It was followed by a particularly bright plasma ejection associated with a superluminal jet component, which has shaped the parsec-scale structure of 3C111 for almost a decade. Here, we present results from 18 epochs of Very Long Baseline Array (VLBA) observations conducted since 1995 as part of the VLBA 2 cm Survey and MOJAVE monitoring programs. This major event allows us to study a variety of processes associated with outbursts of radio-loud AGN in much greater detail than has been possible in other cases: the primary perturbation gives rise to the formation of a leading and a following component, which are interpreted as a forward and a backward-shock. Both components evolve in characteristically different ways and allow us to draw conclusions about the work flow of jet-production events; the expansion, acceleration and recollimation of the ejected jet plasma in an environment with steep pressure and density gradients are revealed; trailing components are formed in the wake of the primary perturbation possibly as a result of coupling to Kelvin-Helmholtz instability pinching modes from the interaction of the jet with the external medium. The interaction of the jet with its ambient medium is further described by the linear-polarization signature of jet components traveling along the jet and passing a region of steep pressure/density gradients.

 

 

and

 

[0710.1326] Magnetar Driven Bubbles and the Origin of Collimated Outflows from GRBs

Magnetar Driven Bubbles and the Origin of Collimated Outflows from GRBs

 

Authors: N. Bucciantini (1), E. Quataert (1), J. Arons (1), B.D. Metzger (1), Todd A. Thompson (2) ((1)Astronomy Department, UC Berkeley, (2)Department of Astrophysical Sciences, Princeton)

(Submitted on 5 Oct 2007)

 

Abstract: We model the interaction between the wind from a newly formed rapidly rotating magnetar and the surrounding progenitor. In the first few seconds after core collapse the magnetar inflates a bubble of plasma and magnetic fields behind the supernova shock, which expands asymmetrically because of the pinching effect of the toroidal magnetic field, as in PWNe, even if the host star is spherically symmetric. The degree of asymmetry depends on the ratio of the magnetic energy to the total energy in the bubble. We assume that the wind by newly formed magnetars inflating these bubbles is more magnetized than for PWNe. We show that for a magnetic to total power supplied by the central magnetar $sim 0.1$ the bubble expands relatively spherically while for values greater than 0.3, most of the pressure in the bubble is exerted close to the rotation axis, driving a collimated outflow out through the host star. This can account for the collimation inferred from observations of long-duration gamma-ray bursts (GRBs). Given that the wind magnetization increases in time, we thus suggest that the magnetar-driven bubble initially expands relatively spherically (enhancing the energy of the associated supernova) while at late times it becomes progressivelymore collimated (producing the GRB). Similar processes may operate in more modestly rotating neutron stars to produce asymmetric supernovae and lower energy transients such as X-ray flashes.

 

This pinching effect of the magnetic fields maybe the key to extracting the degenerate matter that is found in compact objects.

The ejection of degenrate matter changes back to normal matter very quickly. We cannot see the process in action.

 

I'm well awear of the properties of jets. As to their overall density and properties I'll come back to that later.

[REASON]

We also know that by general information that the form that a galaxy takes is directly related to the size and activity of the central black hole. This also implies that the Black hole mass changes by some mechanism meaning that black holes can in release or lose mass.

 

This is unsupported conjecture. How does the variable size and activity of a supermassive black hole at the center of a galaxy *imply* that its mass is changing such that it can release or lose mass. Black holes are either actively consuming matter and increasing mass or stable. I am unaware of any evidence that black holes are capable of releasing or losing mass. If a black hole could release matter, and thus mass, it would not fit the definition of a black hole, which is identified as an object so massive and dense that its gravitation force does not allow even light to escape, much less any form of matter.

 

This shouldn't have to be continually restated in this thread, pluto.

 

 

After reading hundreds of papers from NASA ADS and arXiv there is seems to be no evidence either way to say that black holes cannot eject matter from the core. There is a question mark on the mechanism of how the jets form either from the core or from the disc or a combination of both.

 

This question mark you refer to is only proffered by you and your ilk. Astrophysicists are comfortable in their reasoning that these reletivistic jets do not emanate from the core of black holes.

 

You want these jets to emanate from the core to fit your theory that matter is recycled in black holes. But there is no evidence in support of your theory, even among all of the documents you've linked to. You know why? Because the properties of black holes are such that matter and energy cannot escape. That's why they are called black holes.

 

 

Weak jets tend to form in turbulent areas while stable jets a formed by a strong stable origin possibly near or in the core of a black hole. If we treat the core as compact matter than we can apply physics to the area.

 

This is unsupported conjecture. Saying it over and over wil not make it a reality.

 

 

I'm well awear of the properties of jets. As to their overall density and properties I'll come back to that later.

 

Apparently you are not because you keep saying that they emanate from within black holes. If light cannot escape, neither can jets.

 

Sorry, pluto, but you're barking up a tree with this one.

[freeztar]

Great response Reason!

 

I'd only like to point out that Hawking Radiation is a theoretical mechanism whereby particles can be expelled from the event horizon. Of course, this is for infalling matter, so it's not like the black hole is losing mass it already had.

[CraigD]

I'd only like to point out that Hawking Radiation is a theoretical mechanism whereby particles can be expelled from the event horizon. Of course, this is for infalling matter, so it's not like the black hole is losing mass it already had.

That a black hole is losing mass it already had is exactly what Hawking radiation predicts. Unlike the more common kinds of radiation associated with black holes, which are produced mainly by thermal glowing of their disks of infalling matter, Hawking radiation is predicted to occur even if the black hole is surrounded by no matter or light at all.

 

The problem with Hawking radiation being significant over short periods around star-mass and greater black holes is that its power varies inversely with the square of the mass of the black hole, so the larger the black hole, the less it emits. So, even if the universe had no matter outside of black holes, and was dark at all frequencies of EM radiation, even the smallest stellar black holes would take mind-bogglingly long to “evaporate” – something like [math]10^{68}[/math] years, or, in other units [math]10^{58}[/math] lifetimes of the Sun, a duration that for all practical purposes can be considered infinite. As the universe will be full of matter and light for a long time, present day black holes increase their mass from infalling matter and radiation many times more quickly than they lose it via Hawking radiation.

 

While I can find no theoretical or observational support for Pluto’s idea that neutron stars or black holes just spit degenerate matter out in their disks and jets, I find the question of what would happen if you could remove degenerate matter from a super-dense object like a neutron star an interesting one. Once it is no longer part of a large mass, a lump of matter like neutronium is essentially the enormous nucleus of a nameless unstable element, and should fission like mad. Would it emit free neutrons, which would each beta decay in about 1 minute to produce an atom of hydrogen, or would it do something more exotic? The question is way over my head. :shrug:

[maddog]

I went back and read BBT papers and I must say the huge amounts of papers supporting the the BBT. Than I tried to look at the evidence supporting the BBT. Not one evidence could stand up without an ad hoc idea supporting it. In my opinion the BBT is on weak foundation.

Pluto,

 

You are welcome to your opinion. Excuse us if not all of the rest of us agree with you. :)

 

maddog