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

[Pluto]

G'day From the land of ozzzzzz

Freeztar said:

Quote:
Originally Posted by Pluto
What test did it pass?

Start at the beginning of this thread, and read it through. It's not fair to ask someone to repeat information that has already been given many times through in this very thread.

Yes I know what Modest wrote and yet new readers need to be reminded of the so called evidence.

What I'm saying is:

What evidence is there that cannot be disputed and not be related to another model, totally supporting the BBT.

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

On a topic on origins of jets, that I started to discuss before.

This paper is quite interesting.

[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.

[modest]

Originally Posted by coldcreation

Actually, general relativity has passed every test tossed in its direction (except for those related to gravitational waves). It seems that GR is not to blame for the standard model mishaps. Galactic rotational curves being largely flat (e.g.) does not make GR wrong, nor does it mean CDM is responsible.

In fact, galactic rotation curves leave 2 possibilities:

1. GR is wrong
2. 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.

Furthermore, the predictions of general relativity are fixed; the theory contains no adjustable constants so nothing can be changed. Thus every test of the theory is either a potentially deadly test or a possible probe for new physics. Although it is remarkable that this theory, born 90 years ago out of almost pure thought, has managed to survive every test, the possibility of finding a discrepancy will continue to drive experiments for years to come.

The Confrontation between General Relativity and Experiment (section 7: conclusions)

General Relativity is composed of non-linear partial differential equations that are extremely difficult to solve for any real-world situation. It is, however, possible to find *exact* solutions to GR:

The Einstein field equations are nonlinear and very difficult to solve. Einstein used approximation methods in working out initial predictions of the theory. But as early as 1916, the astrophysicist Karl Schwarzschild found the first non-trivial exact solution to the Einstein field equations, the so-called Schwarzschild metric.

-General relativity

The Schwarzschild metric is an exact solution to GR. It gives exact answers in the setting of a non-rotating spherically symmetric mass. It is, therefore, useful when considering something like a planet or a solar system. There are other such exact solutions and the FLRW metric is one such non-trivial, exact solution.

The best-known exact solutions, and also those most interesting from a physics point of view, are the Schwarzschild solution, the Reissner-Nordström solution and the Kerr metric, each corresponding to a certain type of black hole in an otherwise empty universe,[41] and the Friedmann-Lemaître-Robertson-Walker and de Sitter universes, each describing an expanding cosmos.

-General relativity

From a physics standpoint, this has a lot of meaning. 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.

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.

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

Ned Wright's Javascript Cosmology Calculator

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.

~modest

[Pluto]

G'day from the land of ozzzzzzz

I have some friends reading some of the comments.

They have asked me to ask Modest, can you explain the above, sounds great, but! what does it mean, how does it explain the workings of the parts within the universe?

[modest]

Originally Posted by Pluto

G'day from the land of ozzzzzzz

I have some friends reading some of the comments.

They have asked me to ask Modest, can you explain the above, sounds great, but! what does it mean, how does it explain the workings of the parts within the universe?

Your friends are welcome to join.

CC and I are discussing the concordance model which also goes by the name Lambda-CDM or ΛCDM. You/they can read about it here:

Lambda-CDM model - Wikipedia, the free encyclopedia

Originally Posted by Pluto

how does it explain the workings of the parts within the universe?

The concordance model is a model of the universe. It explains (with specific answers) why a galaxy at some certain distance will have a given brightness, redshift, angular size, etc. It's a model of the universe's past and future based on the physics of General Relativity.

What specific workings or parts of the universe are you/they considering?

~modest

[coldcreation]

Originally Posted by modest

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.

Originally Posted by modest

...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.

Originally Posted by modest

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.

Originally Posted by modest

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.

Originally Posted by modest

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, 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

Originally Posted by modest

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.





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]

Originally Posted by Pluto

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.

Originally Posted by Pluto

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).

Originally Posted by Pluto

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]

Originally Posted by coldcreation

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 ).

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.

Originally Posted by coldcreation

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.

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 , 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 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.

Originally Posted by coldcreation

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]

Originally Posted by modest

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)

Originally Posted by modest

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.

Originally Posted by modest

The indirect evidence is speaking pretty loudly.

True, but direct evidence leaves little to be desired.

Originally Posted by modest

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.

Originally Posted by modest

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.

Originally Posted by modest

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.

Originally Posted by modest

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).

Originally Posted by modest

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.

Originally Posted by modest

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.

Originally Posted by modest

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