Cosmology Fine tuning Intelligent Design

At Phys.org: Can cosmic inflation be ruled out?

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A team of astrophysicists say that cosmic inflation—a point in the universe’s infancy when space-time expanded exponentially, and what physicists really refer to when they talk about the “Big Bang”—can in principle be ruled out in an assumption-free way.

CMBR. Image credit: ESA and the Planck Collaboration – D. Ducros

The astrophysicists, from the University of Cambridge, the University of Trento, and Harvard University, say that there is a clear, unambiguous signal in the cosmos which could eliminate inflation as a possibility. Their paper, published today in The Astrophysical Journal Letters, argues that this signal—known as the cosmic graviton background (CGB)—can feasibly be detected, although it will be a massive technical and scientific challenge.

“Inflation was theorized to explain various fine-tuning challenges of the so-called ‘hot Big Bang’ model,” says the paper’s first author Sunny Vagnozzi who is affiliated with Cambridge’s Kavli Institute for Cosmology and the University of Trento. “It also explains the origin of structure in our universe as a result of quantum fluctuations.”

Note: Here is a statement acknowledging that some scientific theories are promoted not because the they are so robustly supported by the evidence, but due to a commitment to materialism – to avoid the conclusion of divine design. However, the proposed mechanism of cosmic inflation also relies upon layers of fine tuning in order to bring about our present universe. [See Canceled Science, p. 65-66.]

“However, the large flexibility displayed by possible models for cosmic inflation, which span an unlimited landscape of cosmological outcomes, raises concerns that cosmic inflation is not falsifiable, even if individual inflationary models can be ruled out. Is it possible in principle to test cosmic inflation in a model-independent way?” Vagnozzi asks.

Some scientists raised concerns about cosmic inflation in 2013 when the Planck satellite released its first measurements of the cosmic microwave background (CMB), the universe’s oldest light.

“When the results from the Planck satellite were announced, they were held up as a confirmation of cosmic inflation,” says Avi Loeb, Professor of Astronomy from Harvard University and Vagnozzi’s co-author on the new paper. “However, some of us argued that the results might be showing just the opposite.”

Along with Anna Ijjas and Paul Steinhardt, Loeb was one of those who argued that results from Planck showed that inflation posed more puzzles than it solved, and that it was time to consider new ideas about the beginnings of the universe, which, for instance, may have begun not with a bang but with a bounce from a previously contracting cosmos.

The maps of the CMB released by Planck represent the earliest time in the universe humankind could “see,” 100 million years before the first stars formed. We cannot see farther.

“The actual edge of the observable universe is at the distance that any signal could have traveled at the speed-of-light limit over the 13.8 billion years that elapsed since the birth of the universe,” says Loeb. “As a result of the expansion of the universe, this edge is currently located 46.5 billion light years away. The spherical volume within this boundary is like an archaeological dig centered on us: the deeper we probe into it, the earlier is the layer of cosmic history that we uncover, all the way back to the Big Bang which represents our ultimate horizon. What lies beyond the horizon is unknown.”

“It could be possible to dig even further into the universe’s beginnings by studying near-weightless particles known as neutrinos, which are the most abundant particles that have mass in the universe. The universe allowed neutrinos to travel freely without scattering from approximately a second after the Big Bang, when the temperature was ten billion degrees. The present-day universe must be filled with relic neutrinos from that time,” says Vagnozzi.

Vagnozzi and Loeb say we can go even further back, however, by tracing gravitons, particles which mediate the force of gravity.

“The universe was transparent to gravitons all the way back to the earliest instant traced by known physics, the Planck time: 10 to the power of -43 seconds, when the temperature was the highest conceivable: 10 to the power of 32 degrees,” says Loeb. “A proper understanding of what came before that requires a predictive theory of quantum gravity, which we do not possess.”

Vagnozzi and Loeb say that once the universe became transparent to gravitons, a relic background of thermal gravitational radiation with a temperature of slightly less than one degree above absolute zero should have been generated: the cosmic graviton background (CGB).

However, the Big Bang theory does not allow for the existence of the CGB, as it suggests that the exponential inflation of the newborn universe diluted relics such as the CGB to a point that they are undetectable.

This can be turned into a test, the team says: if the CGB were detected, clearly this would rule out the entire cosmic inflation paradigm, which does not allow for its existence.

Vagnozzi and Loeb argue that such a test is possible, and the CGB could in principle be detected in the future. The CGB adds to the cosmic radiation budget, which otherwise includes microwave and neutrino backgrounds. It therefore affects the cosmic expansion rate of the early universe at a level that is detectable by next-generation cosmological probes, which could provide the first indirect detection of the CGB.

However, to claim a definitive detection of the CGB, the “smoking gun” would be the detection of a background of high-frequency gravitational waves peaking at frequencies around 100 GHz. This would be very hard to detect, and would require tremendous technological advances in gyrotron and superconducting magnets technology. Nevertheless, say the researchers, this signal may be within our reach in the future.

Phys.org

6 Replies to “At Phys.org: Can cosmic inflation be ruled out?

  1. 1
    AaronS1978 says:

    Jeesey Creesey sounds similar to another theory I often criticize for the same reasons

    “However, the large flexibility displayed by possible models for cosmic inflation, which span an unlimited landscape of cosmological outcomes, raises concerns that cosmic inflation is not falsifiable, even if individual inflationary models can be ruled out”

    When it comes to the op I hope they can rule out cosmic inflation all together because it would put an end to theories like chaotic inflation that give rise to many forms of multiverse nonsense

  2. 2
    bornagain77 says:

    As to, “Vagnozzi and Loeb say we can go even further back, however, by tracing gravitons, particles which mediate the force of gravity.”,,,

    In the article, Vagnozzi and Loeb give no hint that it is very much likely that gravitons might not even exist in the first place.,,, Gravitons were simply ‘hypothesized’ by men to exist, and were not inferred to exist from actual experimental evidence.

    As the following article states, “In an attempt to marry gravity with quantum theory, physicists came up with a hypothetical particle—the graviton. The graviton remains hypothetical,”,,,

    The Edge of Physics: Do Gravitons Really Exist? – 2018
    Excerpt: Einstein’s theory of relativity described gravity as the distortion of space and time—which bend and stretch based on the masses of objects within them as well as the energy released from the phenomena. A few years later however, we gained awareness of the confusing world of quantum physics as physicists discovered the existence of very small particles—which were later found to affect even the biggest, most powerful phenomena in the universe.
    This led to the discovery of force-carrier particles, or bosons, behind three of the fundamental forces governing the universe: the electromagnetic field has photons, the strong nuclear force has gluons, and the weak force is carried by W and Z bosons. This leaves gravity out. Physicists hypothesize that, if the other three fundamental forces have a corresponding quantum theory, there must be a particle behind gravity too.
    In an attempt to marry gravity with quantum theory, physicists came up with a hypothetical particle—the graviton. The graviton is said to be a massless, stable, spin-2 particle that travels at the speed of light.
    The graviton remains hypothetical, however, because at the moment, it’s impossible to detect.,,,
    https://futurism.com/the-edge-of-physics-do-gravitons-really-exist

    Nor did Vagnozzi and Loeb give any hint of the “severe problems” faced by most theories containing gravitons,,,

    Graviton
    In theories of quantum gravity, the graviton is the hypothetical quantum of gravity, an elementary particle that mediates the force of gravitational interaction. There is no complete quantum field theory of gravitons due to an outstanding mathematical problem with renormalization in general relativity. In string theory, believed to be a consistent theory of quantum gravity, the graviton is a massless state of a fundamental string.,,,
    Difficulties and outstanding issues
    Most theories containing gravitons suffer from severe problems. Attempts to extend the Standard Model or other quantum field theories by adding gravitons run into serious theoretical difficulties at energies close to or above the Planck scale. This is because of infinities arising due to quantum effects; technically, gravitation is not renormalizable. Since classical general relativity and quantum mechanics seem to be incompatible at such energies, from a theoretical point of view, this situation is not tenable. One possible solution is to replace particles with strings. String theories are quantum theories of gravity in the sense that they reduce to classical general relativity plus field theory at low energies, but are fully quantum mechanical, contain a graviton, and are thought to be mathematically consistent.[28]
    https://en.wikipedia.org/wiki/Graviton#Difficulties_and_outstanding_issues

    From their paper we find that they are hoping that “a detection of the CGB would thus provide an experimental test bed for theories attempting to unify quantum mechanics and gravity”. And that the hoped for CGW detection would, (depending on what level CGB would hypothetically be detected at), differentiate between the bouncing model and the (string theoretic) emergent model.

    The Challenge of Ruling Out Inflation via the Primordial Graviton Background
    Sunny Vagnozzi1 and Abraham Loeb – Nov. 2022
    Excerpt: 2. The Cosmic Graviton Background,,,
    ,,, a detection of the CGB would thus provide an experimental test bed for theories attempting to unify quantum mechanics and gravity.,,,
    5. Alternatives to Inflation,,,
    ,,, Within bouncing cosmologies,,, (it is possible) a thermal CGB would be generated and would survive the phase transition between the bouncing and expanding phases.,,,
    ,,, In emergent scenarios,,, the energy density in the emergent phase is close to the Planck density, making it likely for gravitons to be in thermal equilibrium and therefore for a CGB to be generated.
    However, the initial state in string gas cosmology is not a thermal state of particles but of strings, giving a different scaling of thermodynamical quantities. It is therefore unlikely that the string gas CGB takes the blackbody form, although it is in principle possible that its spectral energy density may be higher than our benchmark CGB, enhancing detection prospects.
    https://iopscience.iop.org/article/10.3847/2041-8213/ac9b0e

    To put it mildly, I am extremely skeptical that they will ever detect these hypothetical gravitons via CGW, in order to lend support to the notion that either the ‘bouncing model’ or the ’emergent model’ is correct.

    For instance, we already have experimental evidence that string theory, which lies behind the emergent model, is incorrect.

    According to string theory, all particles in the universe can be divided into two types: bosons and fermions. String theory predicts that a type of connection, called supersymmetry, exists between these two particle types.
    Under supersymmetry, a fermion must exist for every boson and a boson for every fermion. Unfortunately, experiments have not yet detected these extra particles.

    String Theory and Supersymmetry
    Excerpt: According to string theory, all particles in the universe can be divided into two types: bosons and fermions. String theory predicts that a type of connection, called supersymmetry, exists between these two particle types.
    Under supersymmetry, a fermion must exist for every boson and a boson for every fermion. Unfortunately, experiments have not yet detected these extra particles.
    Supersymmetry is a specific mathematical relationship between certain elements of physics equations. It was discovered outside of string theory, although its incorporation into string theory transformed the theory into supersymmetric string theory (or superstring theory) in the mid-1970s.
    One benefit of supersymmetry is that it vastly simplifies string theory’s equations by allowing certain terms to cancel out. Without supersymmetry, the equations result in physical inconsistencies, such as infinite values and imaginary energy levels.
    https://www.dummies.com/education/science/physics/string-theory-and-supersymmetry/

    And as the following 2021 article points out, ‘After years of searching and loads of accumulated data from countless collisions, there is no sign of any supersymmetric particle. In fact, many supersymmetry models are now completely ruled out, and very few theoretical ideas remain valid.’

    Where are all the squarks and gluinos?
    The future of supersymmetry is in serious doubt. – Jan 2021
    Excerpt: The ATLAS collaboration, made up of hundreds of scientists from around the world, have released their latest findings in their search for supersymmetry in a paper appearing in the preprint journal arXiv.
    And their results? Nothing. Nada. Zilch. Zero.
    After years of searching and loads of accumulated data from countless collisions, there is no sign of any supersymmetric particle. In fact, many supersymmetry models are now completely ruled out, and very few theoretical ideas remain valid.
    While supersymmetry has enjoyed widespread support from theorists for decades (who often portrayed it as the obvious next step in advancing our understanding of the universe), the theory has been on thin ice ever since the LHC turned on. But despite those initial doubtful results, theorists had hoped that some model of tuning of the theory would produce a positive result inside the collider experiment.
    While not every possible model of supersymmetry has been ruled out, the future of the theory is in serious doubt. And since physicists have invested so much time and energy into supersymmetry for years, there aren’t a lot of compelling alternatives.
    Where will physics go from here, in a universe without supersymmetry? Only time (and a lot of math) will tell.
    https://www.livescience.com/no-signs-supersymmetry-large-hadron-collider.html

    Thus, String Theory, via the falsification of supersymmetric particles, is found to be, basically, purely mathematical fantasy with no detectable connection to the real world.

    And thus, since the emergent model is based on string theory, we already have fairly strong experimental evidence that all but completely rules out the emergent model.

    Whereas the ‘bouncing/cyclical model’ has its own problems. Specifically, the BGV theorem, when it was recently applied to Ijjas and Steinhardt’s cyclical model, shows that the universe “still has to have a beginning”. Moreover, in the near future when Kinney and Stein apply the BGV theorem to Penrose’s cyclical model they “will likely show,,, (that) it also requires a beginning”.

    Science Journal Reaffirms Universe Had a Beginning, a Key Argument in Meyer’s God Hypothesis
    Brian Miller – August 9, 2022
    Excerpt: A key argument in Stephen Meyer’s Return of the God Hypothesis centers on the universe having a beginning. He argues that the beginning points to the cosmos resulting from the mind of a creator. Meyer’s case for the God Hypothesis includes discrediting the claim that cyclical cosmological models could avoid a beginning by his appealing to the Borde-Guth-Vilenkin (BGV) theorem. His reasoning was recently reaffirmed by University of Buffalo physicists Will Kinney and Nina Stein in their analysis of Ijjas and Steinhardt’s (IS) cosmological model. They published their results in the Journal of Cosmology and Astroparticle Physics.
    Correspondent Charlotte Hsu summarizes the research at Phys.org:
    “People proposed bouncing universes to make the universe infinite into the past, but what we show is that one of the newest types of these models doesn’t work,” says Kinney, Ph.D., professor of physics in the UB College of Arts and Sciences. “In this new type of model, which addresses problems with entropy, even if the universe has cycles, it still has to have a beginning.”
    Cyclical Cosmologies and the BGV Theorem
    Kinney and Stein applied the BGV theorem to the IS model, which I have previously critiqued. Anna Ijjas and Paul Steinhardt propose that the universe expanded, then contracted, and then bounced back into an expansion stage in a never-ending cycle. Each iteration grows vastly larger than the previous one, so the universe is on average always expanding. Kinney and Stein rigorously demonstrate that the BGV theorem mandates the IS model being “geodesically pastincomplete,” meaning that spacetime had an absolute beginning:
    “In this paper, we use the BGV theorem to demonstrate that growth in the scale factor inevitably means that the spacetime is geodesically past-incomplete. … This result is completely general: any bouncing spacetime which obeys the condition for entropy dissipation and the Null Energy Condition outside the bounce must be geodesically incomplete. This is consistent with the BGV theorem, which shows that any spacetime for which the average Hubble parameter is positive must be similarly geodesically incomplete. The IS cosmology satis?es this condition and therefore cannot be past eternal, independent of the details of the dynamics.”
    In the next stage of their research, Kinney and Stein will analyze Penrose’s conformal cyclical cosmology (CCC). As I have reported previously, the CCC model has been severely critiqued by cosmologists including Ethan Siegel for its lack of empirical support and its failed predications. In addition, it requires numerous fine-tuned parameters. By avoiding the evidence for design from a beginning, it requires equal levels of design in its construction. Kinney and Stein will likely show that even if it were true, it also requires a beginning.
    https://evolutionnews.org/2022/08/science-journal-reaffirms-universe-had-a-beginning-a-key-argument-in-meyers-god-hypothesis/

    So again, we already have fairly strong empirical and theoretical reasons to believe that both the ‘bouncing model’ and the ’emergent model’ are incorrect.

    And thus, to repeat, to put it mildly, I am extremely skeptical that they will ever detect these hypothetical gravitons via CGW, in order to lend support to the notion that either the ‘bouncing model’ or the ’emergent model’ is correct.

    Supplemental note as to “attempting to unify quantum mechanics and gravity”

    ,,, And when we rightly allow the agent causality of God ‘back’ into physics, as the Christian founders of modern science originally presupposed, and as is now empirically demanded by the closing of the ‘freedom of choice’ loophole by Anton Zeilinger and company, then that very reasonable concession on our part to rightly allow the Agent causality of God ‘back’ into physics provides us with a very plausible resolution for the much sought after ‘theory of everything’ in that Christ’s resurrection from the dead bridges that infinite mathematical divide that exists between General Relativity and Quantum Mechanics and provides us with an empirically backed reconciliation, (via the Shroud of Turin), between Quantum Mechanics and General Relativity into the much sought after ‘Theory of Everything”
    https://uncommondescent.com/philosophy/at-quanta-magazine-how-godels-proof-works/#comment-768973

    Verse:

    Colossians 1:15-20
    The Son is the image of the invisible God, the firstborn over all creation. For in him all things were created: things in heaven and on earth, visible and invisible, whether thrones or powers or rulers or authorities; all things have been created through him and for him. He is before all things, and in him all things hold together. And he is the head of the body, the church; he is the beginning and the firstborn from among the dead, so that in everything he might have the supremacy. For God was pleased to have all his fullness dwell in him, and through him to reconcile to himself all things, whether things on earth or things in heaven, by making peace through his blood, shed on the cross.

  3. 3
    relatd says:

    More speculative speculation.

    Gravitons? I seriously doubt that. How do planets create/generate gravity? What happens when space rocks get too close to a planet’s gravitational pull? The best description for gravity is this: Gravity describes angular motion. Now before anyone starts thinking about traveling at an angle, think about motion this way. If you accelerate from 0 to 60 MPH in 6 seconds, you are pushed back in your seat. If you are in a large aircraft and begin falling at a speed faster than freefall, what happens? You become weightless. You float around in the cabin. That’s gravity in action, not gravitons.

    Then scientists came up with “dark energy” and “dark matter.” With little evidence for either.

  4. 4
    Querius says:

    Note: Here is a statement acknowledging that some scientific theories are promoted not because the they are so robustly supported by the evidence, but due to a commitment to materialism – to avoid the conclusion of divine design. However, the proposed mechanism of cosmic inflation also relies upon layers of fine tuning in order to bring about our present universe.

    Indeed!

    What I don’t understand is why they seem to have left out the red-shift evidence. Without space-time expansion, they’re left with explaining how some galaxies are traveling faster than the speed of light.

    And without evidence, they seem to reject Einstein’s General Theory of Relativity, “which stands as one of the best-tested theories in science. General relativity predicted many phenomena years before they were observed, including black holes, gravitational waves, gravitational lensing, the expansion of the universe, and the different rates clocks run in a gravitational field.”
    https://www.cfa.harvard.edu/research/science-field/einsteins-theory-gravitation

    -Q

  5. 5
    Querius says:

    Relatd @3,

    Then scientists came up with “dark energy” and “dark matter.” With little evidence for either.

    “Dark matter” (actually better termed transparent matter) is hypothesized due to the significant amount of unaccounted mass that affects galaxy rotation curves.

    “Dark energy” is hypothesized to account for of the expansion of space-time and the red-shift of light coming from the galaxies we observe.

    Neither dark matter or dark energy has been measured directly. They’re only hypothesized as a result of the unexplained phenomena observed.

    -Q

  6. 6
    Querius says:

    Note:
    Because the “the Big Bounce” (cyclical or oscillatory) theory has been discounted due to a comparison of inward gravitational acceleration and outward expansionary acceleration. It’s also been noted that “It is impossible for the universe to be both gravitationally closed (Big Bounce) and geometrically flat.” Measurements seem to indicate that the universe is gravitationally flat (planar), i.e. not a spherical, paraboloid, or hyperboloid gravitational surface. The presence of a Cosmic Microwave Background (CMB) and gravitational waves support the Big Bang theory.

    BUT . . .

    There are also well-known problems with the Big Bang theory, including

    1. What’s the nature and source of “dark energy” that’s accelerating all stars and galaxies away from each other?

    2. Why is there something rather than nothing? What’s the origin of the Big Bang, since mass-energy, space AND time, gravity, dark matter, and the laws of physics all originated at the Big Bang. Without the presence of time, there’s no probability.

    3. Physics and the associated math generally abhor zero-volume points with infinite densities (point masses excepted since they’re finite).

    4. Ideologically, a “beginning” of the universe, even one 13.8 billion years ago, is repulsive to deterministic physicists. Thus, there’s considerable effort to rationalize what “musta” happened to justify an infinite universe of some kind, steady state or cyclical. Loop quantum gravity and many other imaginative possibilities are being mobilized into the effort as a result.

    -Q

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