Page 1 of 2 12 LastLast
Results 1 to 30 of 37

Thread: Simple 'Universal' DM 'halo' calculations

  1. #1
    Join Date
    Aug 2013
    Posts
    586

    Simple 'Universal' DM 'halo' calculations

    There doesn't seem to be an average density of dark matter apart from the usual universal percentages and a mainstream 'universal halo' is purely a model for individual galaxies with virial mass and radius.

    So what can be deduced if dM (or even dE) is considered as a halo of unobserved matter (or energy) that is outside the visible universe but has the same universal mean density of the visible universe?

    The attached image shows the working. Basically the density of the observable universe is considered equal to a larger combined observable and 'dark' matter universe with a larger volume and radius etc.

    Click image for larger version. 

Name:	Universe01.jpg 
Views:	45 
Size:	33.9 KB 
ID:	25206

    The results are shown below with the Observable universe radius (r2) = 1.0, the Observable universe + unobservable 'dark' matter halo (r1) radius, and Observable universe + unobservable 'dark' matter halo + dark energy halo (r3) radius are scaled accordingly.

    i.e. r1 = 1 and simplification gives mean density equivalence as Mo = (Mo + dM)/(r1^3) = (Mo + dM + dE)/(r3^3) or 5 = (5 + 27)/(r1^3) = (5 + 27 + 68)/(r3^3) divided by 5 and inverted gives 1 = r1^3/6.4 = r3^3/20.

    r2 = 1.0
    r1 = 1.85664
    r3 = 2.71442

  2. #2
    Join Date
    Jun 2006
    Posts
    4,832

    What?

    Are you proposing a halo of dark matter and dark energy around the visible universe? If so, why? Can you supply any observations to support this conjecture?
    I'm not a hardnosed mainstreamer; I just like the observations, theories, predictions, and results to match.

    "Mainstream isn’t a faith system. It is a verified body of work that must be taken into account if you wish to add to that body of work, or if you want to change the conclusions of that body of work." - korjik

  3. #3
    Join Date
    Aug 2003
    Location
    The Wild West
    Posts
    9,491
    Quote Originally Posted by John Mendenhall View Post
    Are you proposing a halo of dark matter and dark energy around the visible universe?
    Or is it just a "sphere graph" comparing the volumes of visible and dark matter and dark energy?
    Everyone is entitled to his own opinion, but not his own facts.

  4. #4
    Join Date
    Aug 2013
    Posts
    586
    Quote Originally Posted by John Mendenhall View Post
    Are you proposing a halo of dark matter and dark energy around the visible universe? If so, why? Can you supply any observations to support this conjecture?
    The CMBR observations are effectively made from a single point at the center of a sphere, the visible universe bounded by the CMBR, so this model is based on that observational structure. Outside of this observed 'visible' universe lie other things that are not dark matter or dark energy as described below.

    https://en.wikipedia.org/wiki/Chrono...f_the_universe

    Photon epoch 10 s ~ 370 ka
    The universe consists of a plasma of nuclei, electrons and photons; temperatures remain too high for the binding of electrons to nuclei.

    Recombination 370 ka
    Electrons and atomic nuclei first become bound to form neutral atoms. Photons are no longer in thermal equilibrium with matter and the universe first becomes transparent. Recombination lasts for about 100 ka, during which universe is becoming more and more transparent to photons. The photons of the cosmic microwave background radiation originate at this time.
    https://en.wikipedia.org/wiki/Plasma_(physics)
    Plasma may be the most abundant form of ordinary matter in the universe, although this hypothesis is currently tentative based on the existence and unknown properties of dark matter. Plasma is mostly associated with stars, extending to the rarefied intracluster medium and possibly the intergalactic regions.
    If plasma is the most abundant form of ordinary matter in the universe then the 'unobserved' Photon epoch, prior to the Recombination epoch, can explain 'dark' matter (and even 'dark' energy going back to the Quark epoch) in the context of a 'halo' around the visible universe.

    Also, my simple calculations are not scaled to account for universal expansion, due to the nature of the CMBR observation, and are intended to compare the mean densities (between the epoch's), which should remain the same for an isotropic homogeneous universe.

  5. #5
    Join Date
    Aug 2013
    Posts
    586
    Quote Originally Posted by Cougar View Post
    Or is it just a "sphere graph" comparing the volumes of visible and dark matter and dark energy?
    Please refer to my previous post.

  6. #6
    Join Date
    Mar 2010
    Location
    United Kingdom
    Posts
    7,279
    Quote Originally Posted by LaurieAG View Post
    If plasma is the most abundant form of ordinary matter in the universe then the 'unobserved' Photon epoch, prior to the Recombination epoch, can explain 'dark' matter (and even 'dark' energy going back to the Quark epoch) in the context of a 'halo' around the visible universe.
    Can explain what about dark matter? Because you are going to have to provide a plausible mechanism if you are claiming that a halo of material too far away to be causally linked to us is modifying the rotation curve of our galaxy right now. And as for dark energy - shell theorem. So you need to show why this doesn't apply and how whatever you are proposing can induce changes in the rate of expansion.

  7. #7
    Join Date
    Aug 2013
    Posts
    586
    Quote Originally Posted by Shaula View Post
    Can explain what about dark matter? Because you are going to have to provide a plausible mechanism if you are claiming that a halo of material too far away to be causally linked to us is modifying the rotation curve of our galaxy right now. And as for dark energy - shell theorem. So you need to show why this doesn't apply and how whatever you are proposing can induce changes in the rate of expansion.
    There are obvious conceptual issues with regards to viewing the observational context as represented in this thread although they are the same conceptual issues with regards to modelling and analyzing the CMBR, the Big Bang and even Lambda CDM within a visible universe. As such I am not proposing any changes to the rate of inflation, I am using an unscaled constant mean density to reflect what both the BB and Lambda CDM interpretations imply in the context of the observational model.

    On reflection it would be more correct to discard the notion of r1 and just regard r3 as the start of the plasma which existed at the end of the opaque Photon epoch just prior to the beginning of the Recombination epoch (when the universe started to become transparent) and r2 as the end of the Recombination epoch or thereabouts (when the universe became 'fully' transparent). In this context a scaled spherical model would show our visible universe from the observation point out to the CMBR with a much thinner but very dense plasma layer surrounding it.

    As the anisotropies evident in the CMBR have been measured in detail and according to Wikipedia:-

    match what would be expected if small thermal variations, generated by quantum fluctuations of matter in a very tiny space, had expanded to the size of the observable universe we see today.
    Then it is not unreasonable to expect that the photon rich plasma, that permeated the universe in the Photon epoch prior to the Recombination epoch (and much of which still exists in our universe today in large amounts), was also present in the CMBR as a 'background' for the anisotropies that evolved until the universe became 'fully' transparent at the 'end' of the Recombination epoch. In a similar way the matter between galaxies is not considered in galaxy rotation curves/shell theorem apart from that amount necessary to satisfy virial conditions.

    In effect the CMBR could contain the photons from 2 epoch's, in the observational context, and this double counting could be the real source for 'dark' matter and 'dark' energy.

  8. #8
    Join Date
    Mar 2010
    Location
    United Kingdom
    Posts
    7,279
    So you are proposing:
    - An 'explanation' for dark matter that doesn't fix galactic rotation curves, nucleosynthesis or any of the other reasons it was hypothesised
    - An 'explanation' for dark energy that doesn't change the expansion rate, which is the main reason it has been postulated in the form that it has

    Not sure what your idea really adds to our models of the universe then. And that is before we get into the implausibility of the physics in it.

  9. #9
    Join Date
    Aug 2013
    Posts
    586
    Quote Originally Posted by Shaula View Post
    So you are proposing:
    - An 'explanation' for dark matter that doesn't fix galactic rotation curves, nucleosynthesis or any of the other reasons it was hypothesised
    - An 'explanation' for dark energy that doesn't change the expansion rate, which is the main reason it has been postulated in the form that it has

    Not sure what your idea really adds to our models of the universe then. And that is before we get into the implausibility of the physics in it.
    You may not be aware of the NASA Cosmic Infrared Background ExpeRiment (CIBER) results, released in 2014, that found that there were as many stars between galaxies as there were within galaxies and that this was not due to light from ancient galaxies. The discovery of these stars (along with plasma) could help solve the 'photon underproduction crisis' and 'missing baryon problem' as the baryons that astronomers have accounted for in the local cosmic neighborhood are only half of those predicted to exist in that region.

    NASA Rocket Redefines What Astronomers Think of as Galaxies
    https://science.nasa.gov/science-new...14/06nov_ciber
    http://www.ciber.caltech.edu/rocket.html

    https://en.wikipedia.org/wiki/Big_Bang_nucleosynthesis
    Big Bang nucleosynthesis began roughly 10 seconds after the big bang, when the universe had cooled sufficiently to allow deuterium nuclei to survive disruption by high-energy photons. (Note that the neutron-proton freeze-out time was earlier). This time is essentially independent of dark matter content, since the universe was highly radiation dominated until much later, and this dominant component controls the temperature/time relation. At this time there were about six protons for every neutron, but a small fraction of the neutrons decay before fusing in the next few hundred seconds, so at the end of nucleosynthesis there are about seven protons to every neutron, and almost all the neutrons are in Helium-4 nuclei.
    ...
    During the 1970s, there was a major puzzle in that the density of baryons as calculated by Big Bang nucleosynthesis was much less than the observed mass of the universe based on measurements of galaxy rotation curves and galaxy cluster dynamics. This puzzle was resolved in large part by postulating the existence of dark matter.
    The whole problem seems to boil down to conception and 'fine tuning' as extending a galaxies virial radius by a ratio of 1.25992 will lead to an equal population of stars with the same stellar density in a thin halo outside the galaxy as within its virial radius (and lower average velocities). Also consider that using 0.79370 of the virial radius will leave half of the stars, the stars causing the 'galaxy rotation problem', outside the galaxy.

  10. #10
    Join Date
    Mar 2010
    Location
    United Kingdom
    Posts
    7,279
    Quote Originally Posted by LaurieAG View Post
    You may not be aware of the NASA Cosmic Infrared Background ExpeRiment (CIBER) results, released in 2014, that found that there were as many stars between galaxies as there were within galaxies and that this was not due to light from ancient galaxies. The discovery of these stars (along with plasma) could help solve the 'photon underproduction crisis' and 'missing baryon problem' as the baryons that astronomers have accounted for in the local cosmic neighborhood are only half of those predicted to exist in that region.
    I'm well aware of them. And aware that they are not even close to the density or distribution required to fix the rotation curve problem so largely irrelevant to my points.

    And you've misunderstood my point about nucleosynthesis. Nucleosynthesis proceeded independent of dark matter - but the initial conditions from which it started and the final state required that dark matter didn't take part in nucleosynthesis, something extra baryonic matter would. So just adding more stars doesn't work as the ratio of elements produced would be very different if the dark matter were baryonic.

    So we get back to this - You've proposed an idea that solves no problems without introducing more even more problems (problems that are either completely against observational evidence or are incompatible with theories which have been extensively tested).

    Edit to add - So my direct questions are: Show in detail what you think are the key predictions of your idea and how they address the underlying issues you claim that they do. Present a compelling case why we should accept the implausible mechanisms and impossible physics you have so far presented over existing theories.

  11. #11
    Join Date
    Apr 2020
    Posts
    1
    n the current cold dark matter (CDM) paradigm of structure formation, a key ... it is easy to calculate s(M) for a halo of mass Mobs at a given redshift zobs.
    by DH Zhao - ‎2009 - ‎Cited by 402 - ‎Related articles

  12. #12
    Join Date
    Aug 2013
    Posts
    586
    Quote Originally Posted by noor1 View Post
    n the current cold dark matter (CDM) paradigm of structure formation, a key ... it is easy to calculate s(M) for a halo of mass Mobs at a given redshift zobs.
    by DH Zhao - ‎2009 - ‎Cited by 402 - ‎Related articles
    Thanks, they also said:-

    It should be pointed out that both our model and the model of NFW are based on the correlation between halo concentration and a characteristic formation time. However, the two models have several important differences. First, in the NFW model the formation time was defined as the epoch when half of the halo mass M has been assembled in its progenitors of masses exceeding 0.01M, while in our model the time is defined as the epoch when its main progenitor has gained 4% of the halo mass. Second, the ways to relate the concentration to the characteristic time are also different. NFW assumed that the inner density at Rs of a halo is proportional to the mean density of the universe at the formation time, while we relate the halo concentration and the characteristic time by Equation (13). Finally, NFW used the extended Press–Schechter formula to compute the formation time, while we use our model of MAHs to calculate the time t0.04. These differences make a very big difference in the model predictions, as shown above.
    It appears from equation (13) that the halo's mass concentration (dM and dE?) is closely related to a growing galaxy when its ordinary matter % is close to the ordinary matter % of the Lambda CDM model.

  13. #13
    Join Date
    Aug 2008
    Location
    Wellington, New Zealand
    Posts
    4,415
    Quote Originally Posted by LaurieAG View Post
    So what can be deduced if dM (or even dE) is considered as a halo of unobserved matter (or energy) that is outside the visible universe but has the same universal mean density of the visible universe?
    ...
    The answer seems obvious but might not be - nothing. Surround the universe with a symmetrical spherical distribution of dark matter with constant density and it will have no effect according to the shell theorem.

    Your next post has lots of errors: The universe has no center (not even an effective center). The CMBR was emitted throughout the visible universe, not emitted from a boundary as "bounded by the CMBR" implies. We have no evidence about what is outside of the visible universe so we have use the assumption that it is not different, i.e. has the same matter, dark matter and dark energy. Plasma being the most abundant normal matter says nothing about dark matter. The Photon Epoch cannot explain dark matter because the hypothetical particles would be already exist - created in the Planck Epoch with energies of many Tev.

    You should review the evidence for dark matter and that it is not only the CMBR or galaxy rotation curves: Observational evidence
    Last edited by Reality Check; 2020-May-11 at 09:49 PM.

  14. #14
    Join Date
    Aug 2013
    Posts
    586
    Quote Originally Posted by Reality Check View Post
    You should review the evidence for dark matter and that it is not only the CMBR or galaxy rotation curves: Observational evidence
    This is also at the bottom of the page.

    https://en.wikipedia.org/wiki/Dark_m...phy_of_science
    In philosophy of science

    In philosophy of science, dark matter is an example of an auxiliary hypothesis, an ad hoc postulate added to a theory in response to observations which falsify it. It has been argued the dark matter hypothesis is a conventionalist hypothesis, that is, a hypothesis which adds no empirical content and hence is unfalsifiable in the sense defined by Karl Popper.[170]
    I referred to the conceptual issues with regards to the CMB observation, the visible universe and the BB model etc, in my third post. I have also seen statements where emitted photons that form the CMBR were all at t=0 and that dM existed before the Recombination epoch back to the BB and even before so, as I stated, this is an attempt to view the problem in the observational context without getting into unscientific dM 'belief' or conventionalist scientific fine tuning.

    If photons all travel at c from their point of emission in a line to the observer, while gradually stretching to the microwave frequencies seen from the CMB observations over time, then we can regard determining the 100,000 years from when the first photons to the last photons were emitted as being beyond our current measurement capability, but we cannot explain away the fact that our observation model requires that the observer is relatively equidistant from the emitting sources at the discrete observation point at the discrete time of the observation.

    This is a disconnect with regards to the BB model, which works outwards (backwards in the CMB observational context) from a single point, and the CMBR that was 'produced' at the end of the BB Recombination epoch and the observation of those photons, emitted from a great distance, that arrive at the center of a very large observational sphere. Coupling classical Newtonian type physics, like the Virial theorem, to justify dM in galaxies(albeit not universally) is also a disconnect between the methodologies which, while they may provide 'consistent' results belie the 'universality of physical laws' and are a more extreme version of fine tuning. Changing the criteria of multiples of critical density from 200 to 150 will also fine tune the result, remove faster stars, and therefore remove the need for dM.

    And if we are going to mix and match the 'universality of physical laws' and fine tune things how we like we may as well claim that many photons went into black holes, as it was an anti-de Sitter 'space' without mass before the first mass emerged, the universal 'space' then became unstable, changed (from anti-de Sitter space), and started expanding as a result, and the missing photons have stayed there the entire time without any dM.

    https://arxiv.org/abs/1812.04268
    https://www.quantamagazine.org/black...able-20200511/
    In a series of advances that began in 2017 and continue to this day, Moschidis has shown that a certain canonical configuration of Einsteinian space-time called anti-de Sitter (AdS) space is unstable. Throw a tiny bit of matter into AdS space, and eventually a black hole will emerge.
    ...
    The proof involves injecting a small bit of matter into the space-time, akin to dropping a stone into a pond. Waves ripple out and back, interacting in a way that eventually creates a black hole.

  15. #15
    Join Date
    Mar 2010
    Location
    United Kingdom
    Posts
    7,279
    You still haven't answered my questions about your idea. Am I to take that you don't have any examples of predictions you can make and cannot provide any reason that your ideas about dark matter are relevant to the observed universe? Because at the moment you are proposing particularly useless kinds of dark matter and energy that don't fix any of the issues that dark matter and energy were proposed to account for. You can list your objections to the current models as much as you like - it doesn't make anything you have proposed any more relevant or useful. You can only do that by showing how your ideas explain observations better than current models. Which so far you can only do even conceptually if you introduce a whole lot of magical thinking and more ad hoc parameters than DM/DE have.

  16. #16
    Join Date
    Aug 2008
    Location
    Wellington, New Zealand
    Posts
    4,415
    Quote Originally Posted by LaurieAG View Post
    This is also at the bottom of the page. ...
    You did not state any "conceptual issues" and they would not make the observational evidence for dark matter from many lines of evidence wrong. To make this clear, a formal question:
    IF01: State the conceptual issues that make applying the virial theorem to galaxy clusters and finding that there is matter that is not visible invalid, LaurieAG.
    Dark matter
    In 1933, Swiss astrophysicist Fritz Zwicky, who studied galaxy clusters while working at the California Institute of Technology, made a similar inference.[28][29][30] Zwicky applied the virial theorem to the Coma Cluster and obtained evidence of unseen mass he called dunkle Materie ('dark matter'). Zwicky estimated its mass based on the motions of galaxies near its edge and compared that to an estimate based on its brightness and number of galaxies. He estimated the cluster had about 400 times more mass than was visually observable. The gravity effect of the visible galaxies was far too small for such fast orbits, thus mass must be hidden from view. Based on these conclusions, Zwicky inferred some unseen matter provided the mass and associated gravitation attraction to hold the cluster together.[31] Zwicky's estimates were off by more than an order of magnitude, mainly due to an obsolete value of the Hubble constant;[32] the same calculation today shows a smaller fraction, using greater values for luminous mass. Nonetheless, Zwicky did correctly conclude from his calculation that the bulk of the matter was dark.[21]
    The rest of the post has errors and an irrelevant paper.
    What happened to create the cosmic microwave background was that the universe was in a hot dense state. That means that everything was ionized. That mans that any emitted photons were quickly absorbed - the universe was opaque. As the universe expanded, temperature and density dropped. At about t = 379,000 years, neutral matter formed and photons were no longer strongly absorbed - the universe became transparent. It is these photons that make up the CMBR. The CMBR is a bath of photons filling the universe and red shifting to microwaves due to the expansion of the universe.
    We can measure the CMBR! We can measure what the universe did to the CMBR photons before they were emitted. That gives us about 379,000 years of measurement before the CMBR was emitted. From memory we have physical evidence for the state of the universe back to t = 10-13 seconds.

    The BB model does not "work outward ..from a single point" . GR states that our universe must be contracting, expanding or unstably static. The physical evidence says the universe is expanding. We construct the BB model by taking the current universe, reversing time and applying the laws of physics. That gest us to a state of the universe where our physics breaks down (the BB singularity). That tells us that we cannot apply current physics at t = 0 and we have a BB model that starts at t > 0 and a universe that is not a single point.
    The CMBR was produced (no quotes) at the recombination event (not epoch).
    The CMBR was produced throughout the universe - there is no "observational sphere".
    The virial theorem can be applied to any Newtonian system such as stars in a galaxy or global cluster or galaxies in a cluster. GR is only needed for strong gravitational fields or relativistic speeds.
    Last edited by Reality Check; 2020-May-13 at 10:16 PM.

  17. #17
    Join Date
    Aug 2013
    Posts
    586
    Shaula and RC, I will respond to your last two posts and then discuss the "conceptual issues" below.

    Quote Originally Posted by Shaula View Post
    Am I to take that you don't have any examples of predictions you can make and cannot provide any reason that your ideas about dark matter are relevant to the observed universe?
    I have provided an observational model that puts all of the 'matter' that has not been revealed to be made of anything known in modern physics in a 'halo' beyond our visible universe to match the numbers given by Lambda CDM. I have also shown how the Virial theorem can be manipulated in a similar way to provide a consistent measure for all galaxies including those which have been revealed to have no 'dark' matter, without a dM halo.

    Quote Originally Posted by Reality Check View Post
    You did not state any "conceptual issues" and they would not make the observational evidence for dark matter from many lines of evidence (https://en.wikipedia.org/wiki/Dark_m...ional_evidence) wrong. To make this clear, a formal question:
    *IF01*: State the conceptual issues that make applying the Virial theorem to galaxy clusters and finding that there is matter that is not visible invalid, *LaurieAG*.
    Per my response to Shaula above the issue is that the 'matter', that is not visible and whose composition doesn't exist in modern physics, is a conceptual issue.

    Quote Originally Posted by Reality Check View Post
    We can measure the CMBR! We can measure what the universe did to the CMBR photons before they were emitted. That gives us about 379,000 years of measurement before the CMBR was emitted. From memory we have physical evidence for the state of the universe back to t = 10-13 seconds.
    ...
    The CMBR was produced (no quotes) at the recombination event (not epoch). The CMBR is a bath of photons filling the universe and red shifting to microwaves due to the expansion of the universe.
    ...
    The CMBR was produced throughout the universe - there is no "observational sphere".
    https://en.wikipedia.org/wiki/Chrono...abular_summary
    Recombination lasts for about 100 ka, during which universe is becoming more and more transparent to photons. The photons of the cosmic microwave background radiation originate at this time. The spherical volume of space which will become the observable universe is 42 million light-years in radius at this time. The baryonic matter density at this time is about 500 million hydrogen and helium atoms per m3, approximately a billion times higher than today.
    We can measure what happens on atomic scales and the particles that are emitted through experimental apparatus like the LHC but we cannot 'measure' the universe beyond the CMBR limit. Per my original thread in ATM we make observations of emitted photons that travel over large distances at c in a relatively straight line from a source to a relatively fixed point at the time of the observation. The CMBR observations from PLANCK and WMAP were made from a relatively compact stationary location (1-2LY) over a relatively minor observation time (1-2Y), compared with the distance travelled by the observed photons which were stretched to microwaves (13.8 billion Y).

    Also, some of the oldest identified stars in the universe, created during the 100 ka of the CMBR 'production', exist in the Milky Way and, considering their observed distances from us, it would be difficult to consider that their emitted photons are included in the CMBR.

    https://en.wikipedia.org/wiki/List_of_oldest_stars

    Conceptual Issues

    Shaula and RC, perception can be "the ability to see, hear, or become aware of something through the senses" (physically observe) or "the way in which something is regarded, understood, or interpreted." (think) and a misconception is "a view or opinion that is incorrect because based on faulty thinking or understanding."

    In my first thread in ATM, many people had a misconception about the observational model presented while RC was one of the few people who eventually recognized the concept as being in the mainstream. https://forum.cosmoquest.org/showthr...tating-sources

    At one observational extreme 'nebula' originally described galaxies and clouds of gas before our observations could identify the individual stars that made up galaxies. A modified virial radius can remove the galaxy relation problem if we either widen or lessen the scope of what exactly forms a galaxy i.e. do we include or exclude all of stars that are on their way out, can we identify them as such or even include all of them? At the other observational extreme we know that light that travels enormous distances stretches and creates a natural 'barrier' to the visible universe that we cannot physically observe past. We can back calculate from a point based on atomic research but we cannot observe past the CMBR limit.

    So should we ignore one or the other extreme or both just because we get convenient solutions but cannot identify what actually creates these solutions within modern physics?

    I have provided a simple model that matches how we physically observe the CMBR experimentally and have extended this model outwards to provide a place for the 'missing matter' that does not require thinking that the 'matter' is something that doesn't exist in modern physics, it is just in a location we cannot observe.

  18. #18
    Join Date
    Mar 2010
    Location
    United Kingdom
    Posts
    7,279
    Quote Originally Posted by LaurieAG View Post
    I have provided a simple model that matches how we physically observe the CMBR experimentally and have extended this model outwards to provide a place for the 'missing matter' that does not require thinking that the 'matter' is something that doesn't exist in modern physics, it is just in a location we cannot observe.
    This doesn't address any of the issues I have pointed out.

    What you are doing is breaking the current model, adding in magical physics and new finely tuned ad hoc parameters (that are for some reason 'better' than the ones you criticise in the current models) to create a framework so vague and poorly constrained that it predicts nothing and answers no questions. Until you produce something substantive and relevant to actual physics I'm going to regard this as a waste of time and bow out. All of your responses so far have been non-responses where you use a my comments as an excuse to post more irrelevant stuff while ignoring the questions or problems posed.

  19. #19
    Join Date
    Aug 2008
    Location
    Wellington, New Zealand
    Posts
    4,415
    Quote Originally Posted by LaurieAG View Post
    We can measure what happens on atomic scales....
    IF02: Give your sources that state we cannot "'measure' the universe beyond the CMBR limit" or give your own work, LaurieAG.
    An obvious answer is that you are wrong because we can measure the universe back to tiny times.

    The real limit to measurements is the inflationary epoch.

    Irrelevant stuff abut the CMBR and our detection of it before an obviously wrong "some of the oldest identified stars in the universe, created during the 100 ka of the CMBR 'production'" assertion. Stars did not exist during the actual CMBR production (no quotes).
    IF03: Give your sources that detected stars created between ~ 290,00 and 390,000 years ago, LaurieAG.
    List of oldest stars.
    You have already given and quoted from a source that debunks your own assertion! Chronology of the universe: No stars during recombination mentioned, Dark Ages are "The time between recombination and the formation of the first stars" and "Earliest galaxies: from about ?300-400 Ma (first stars: similar or earlier)".

    IF01: State the conceptual issues that make applying the virial theorem to galaxy clusters and finding that there is matter that is not visible invalid, LaurieAG.
    Last edited by Reality Check; 2020-May-17 at 10:03 PM.

  20. #20
    Join Date
    Aug 2013
    Posts
    586
    RC, As far as I am aware the BICEP2 results were invalid because the entire signal could be accounted for as dust. If you have any mainstream references related to 'seeing' beyond the CMB please post them as all I can find are references to Dark Flow, and the Practical horizons section in Cosmological Horizons in Wikipedia. The first quote below is referring to the age problem of the oldest star. further comments on the Virial theorem etc are at the bottom.

    https://en.wikipedia.org/wiki/Cosmol...tical_horizons

    https://www.space.com/how-can-a-star...-universe.html
    "Like all measured estimates, it is subject to both random and systematic error," said physicist Robert Matthews of Aston University in Birmingham, UK, who was not involved in the study. "The overlap in the error bars gives some indication of the probability of a clash with cosmological age determinations," Matthews said. "In other words, the best supported age of the star is in conflict with that for the derived age of the universe [as determined by the cosmic microwave background], and the conflict can only be resolved by pushing the error bars to their extreme limits."
    https://www.discovermagazine.com/the...f-the-universe
    The visible edge of the universe is, by definition, the most distant thing that we can see. That does not mean it is the most distant thing we can feel, however.

    According to astrophysicist Alexander Kashlinsky of NASA’s Goddard Space Flight Center, something from way beyond the edge seems to be pulling powerfully on galaxies in our universe, yanking them along in a motion he calls “dark flow.”

    Kashlinsky and his team noticed this phenomenon while studying the cosmic microwave background, radiation left over from just after the Big Bang. Giant clusters of galaxies scatter the radiation in a way that makes it possible to determine how each cluster is moving. When Kashlinsky plotted those motions, he determined that the galaxies seem to be racing in a particular direction, roughly aligned with the constellation Centaurus. The phenomenon was so unexpected that he conducted an expanded survey, looking at more and brighter galaxy clusters.

    The results, released last March, not only confirm the dark flow but extend its known reach. “This motion persists as far as we can see,” Kashlinsky says.

    Nothing in the known universe can account for the dark flow phenomenon. So Kashlinsky thinks the galaxies are responding to the pull of matter and energy lying beyond our cosmic horizon. That unseen stuff could be at least a thousand times farther out than the horizon and cause “a slight tilt to our universe,” he theorizes.

    Kashlinsky plans to use the European Space Agency’s new Planck spacecraft to make refined measurements of the dark flow to better understand what is causing it.
    https://en.wikipedia.org/wiki/Dark_flow
    The researchers had suggested that the motion may be a remnant of the influence of no-longer-visible regions of the universe prior to inflation. Telescopes cannot see events earlier than about 380,000 years after the Big Bang, when the universe became transparent (the cosmic microwave background); this corresponds to the particle horizon at a distance of about 46 billion (4.6×1010) light years. Since the matter causing the net motion in this proposal is outside this range, it would in a certain sense be outside our visible universe; however, it would still be in our past light cone.
    There are also many papers out there which refer to the virial theorem and problems with the Lambda CDM model such as these below.

    https://www.mdpi.com/2075-4434/5/1/17
    https://arxiv.org/abs/1606.07790

    One of the main problems seems to be with regards to fine tuning and resolving issues on smaller scales without breaking the model and how the Hubble tension impacts on measurements. I can understand how those fine tuning constraints can cause real problems.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	DMhalo calcs 1.jpg 
Views:	15 
Size:	44.2 KB 
ID:	25242  

  21. #21
    Join Date
    Aug 2008
    Location
    Wellington, New Zealand
    Posts
    4,415
    Quote Originally Posted by LaurieAG View Post
    RC, As far as I am aware the BICEP2 results were invalid because the entire signal could be accounted for as dust. ...
    That is correct and not my point. As I wrote: "The invalid BICEP2 results is a well known example of the information that we expect to have from before t = 390,000 years. Primordial gravitational waves also come from inflation. (emphasis added). Inflation is a period at t ~ 10-32 seconds which is less than t ~ 390,000 (the CMBR).

    Read (and answer) my IF02: Give your sources that state we cannot "'measure' the universe beyond the CMBR limit" or give your own work, LaurieAG post for the Wikipedia articles citing mainstream references related to seeing beyond the CMB.

    IF03: Give your sources that detected stars created between ~ 290,00 and 390,000 years ago, LaurieAG has List of oldest stars which included HD 140283 or the Methuselah Star which has an age of 14.46 ± 0.8 billion years. That is not a star formed during the CMBR formation which is your claim. It is a star whose age in 2013 was calculated as older than the universe. The uncertainty means its age may be similar to the other oldest stars (13 to 13.53 billion years).

    ETA: The Wikipedia article is out of date. The age of HD 140283 in 2013 needed the distance and thus luminosity of the star. This was found from parallax from Hubble measurements. Since then we have had the Gaia spacecraft measuring more precise parallax.
    Benchmark stars for Gaia Fundamental properties of the Population II star HD 140283 from interferometric, spectroscopic, and photometric data gets an age of 13.7 ± 0.7 Gyr (zero reddening) or 12.2 ± 0.6 Gyr (maximum reddening).

    An irrelevant paper does not answer my question.
    IF01: State the conceptual issues that make applying the virial theorem to galaxy clusters and finding that there is matter that is not visible invalid, LaurieAG.

    Small Scale Problems of the ΛCDM Model: A Short Review (pre-print). There is are conceptual problems with the virial theorem applied to galaxy clusters in that paper. There is no virial theorem applied to galaxy clusters at all! The word virial appears 10 times as virial mass or virial radius which are the application of the virial theorem.
    Last edited by Reality Check; 2020-May-19 at 10:06 PM.

  22. #22
    Join Date
    Aug 2013
    Posts
    586
    IF01, there is a major difference between the critical overdensity constant, Δc, derived via the ΛCDM model results and that used in the virial radius and virial mass calculations for galaxies.

    https://en.wikipedia.org/wiki/Virial_mass#Virial_radius
    Compare this to the currently accepted cosmological model for the Universe, ΛCDM model, where Ωm = 0.3 and ΩΛ = 0.7 in this case, Δc ≈ 100. Nevertheless, it is typically assumed that Δc = 200 for the purpose of using a common definition, and this is denoted as r200 for the virial radius and M200 for the virial mass.
    IF02, from NASA.
    https://science.nasa.gov/observable-universe
    In visible light, the farthest we can see comes from the cosmic microwave background, a time 13.8 billion years ago when the universe was opaque like thick fog. Some neutrinos and gravitational waves that surround us come from even farther out, but humanity does not yet have the technology to detect them.
    IF03, even the Gaia values have a large error range and the article I quoted said:-
    "In other words, the best supported age of the star is in conflict with that for the derived age of the universe [as determined by the cosmic microwave background], and the conflict can only be resolved by pushing the error bars to their extreme limits."
    The ages of (the oldest) stars
    https://arxiv.org/abs/1709.08656v2
    Parallax measurements for HD140283. The Gaia value (TGAS in the plot, after Tycho-Gaia Astrometric Solution) deviates significantly from the one obtained with HST in particular, which in turn is fully consistent with the Hipparcos value.
    Benchmark stars for Gaia: fundamental properties of the Population II star HD140283 from interferometric, spectroscopic and photometric data
    https://arxiv.org/abs/1410.4780
    We give an equation to estimate t from M, Yi (α), and AV . Establishing a reference α = 1.00 and adopting Yi = 0.245 we derive a mass and age of
    HD140283: M = 0.780 ± 0.010 M⊙ and t = 13.7 ± 0.7 Gyr (AV = 0.0 mag), or M = 0.805 ± 0.010 M⊙ and t = 12.2 ± 0.6 Gyr (AV
    = 0.1 mag).

  23. #23
    Join Date
    Aug 2008
    Location
    Wellington, New Zealand
    Posts
    4,415
    Quote Originally Posted by LaurieAG View Post
    IF01, ...
    Not an answer to my questions.
    IF01: State the conceptual issues that make applying the virial theorem to galaxy clusters and finding that there is matter that is not visible invalid, LaurieAG.
    IF02: Give your sources that state we cannot "'measure' the universe beyond the CMBR limit" or give your own work, LaurieAG
    IF03: Give your sources that detected stars created between ~ 290,00 and 390,000 years ago, LaurieAG

    IF01 is not a question abut critical density.
    IF02: The NASA observable universe is mostly correct. The earliest light we can detect is the CMBR but its fluctuations let us 'measure' (but we cannot 'measure' the universe beyond the CMBR limit) back to inflation. Astronomy is not limited to light. Neutrino observatories exist (not used for the CνB evidence though). Indirect evidence for the CνB. We can study the CMBR and detect any possible gravitational waves.
    IF03: You still do not list the stars that have been measured to have been created between ~ 290,00 and 390,000 years ago.

    HD 140283 has an age of 14.46 ± 0.8 billion years calculated in 2013. If we take 14.4 billion years as set in stone then this is irrelevant to your claim - this star was created before ~ 290,000 years ago. If we look at the uncertainty then we only know that it was created between 13.66 and 15.4 billion years ago and it is irrelevant to your claim again.
    Benchmark stars for Gaia Fundamental properties of the Population II star HD 140283 from interferometric, spectroscopic, and photometric data gets an age of 13.7 ± 0.7 Gyr or 12.2 ± 0.6 Gyr using more precise Gaia data.
    Last edited by Reality Check; 2020-May-21 at 04:35 AM.

  24. #24
    Join Date
    Aug 2013
    Posts
    586
    IF01: The Virial theorem is about critical overdensity (giving the Virial mass and Virial radius) and there is a major discrepancy between the critical overdensity of the ΛCDM model (100) and that used for galaxies (200). As I stated previously, if we halve the difference between the two (150) we exclude the stars that cause the galaxy rotation problem and the matter that cannot be identified to be made from anything in our modern physics is invalid.

    https://arxiv.org/abs/1606.07790
    In fact, so few halo baryons assemble in actual galaxies that the correlation with virial mass is unclear, while, as the disk sizes remain so small compared to the estimated virial sizes of galaxy haloes, scaling between their two characteristic velocities appears unrealistic. In addition, baryonic feedback mechanisms determining the galaxies’ baryonic masses seems too variable to ensure similar galactic baryon fractions for all haloes.
    IF02: You link the Wikipedia page that linked from the Practical Horizons page that agrees with the NASA page.

    IF03: The "more precise* Gaia data calculations use the *more precise* value (also from Gaia) for the Hubble constant (and the age of the universe) so the two figures are the same (8% difference) and, within the error bars, the star could have been created between ~ 290,00 and 390,000 years after the big bang.

    HD 140283 is measured as being 190LY away from us (minimal redshift) so there should also be a large sphere around the observer in the practical observable universe where it is impossible for photons from the CMBR to be redshifted enough to arrive at the observers location during the time of the observation because they have past by already, expansion or otherwise. In the observational model the observer can only observe those photons that would have arrived at that discrete location during the observation period regardless of whether the observer was there or not.

  25. #25
    Join Date
    Aug 2008
    Location
    Wellington, New Zealand
    Posts
    4,415
    Quote Originally Posted by LaurieAG View Post
    IF01: The Virial theorem is about critical overdensity ....
    Repeating the same irrelevancy (and ignorance) does not answer my questions:
    IF01: State the conceptual issues that make applying the virial theorem to galaxy clusters and finding that there is matter that is not visible invalid, LaurieAG.
    IF02: Give your sources that state we cannot "'measure' the universe beyond the CMBR limit" or give your own work, LaurieAG
    IF03: Give your sources that detected stars created between ~ 290,00 and 390,000 years ago, LaurieAG

    This is the Virial theorem
    In mechanics, the virial theorem provides a general equation that relates the average over time of the total kinetic energy of a stable system of discrete particles, bound by potential forces, with that of the total potential energy of the system.
    This is a galaxy cluster. Zwicky applied the virial theorem to the Coma galaxy cluster. Explained at Using the virial theorem: the mass of a cluster of galaxies.

    The NASA page does not state that we cannot 'measure' (e.g. use the CMBR fluctuations to measure properties of the universe) earlier the CMBR. As you quoted "In visible light, the farthest we can see comes from the cosmic microwave background, a time 13.8 billion years ago when the universe was opaque like thick fog. Some neutrinos and gravitational waves that surround us come from even farther out, but humanity does not yet have the technology to detect them.". See is not your measure which is the wider concept of being able to deduce the existence of something from data. We do not see dark matter but we do measure dark matter from its effects. Likewise we measure the effects of inflation and density fluctuations before ~390,000 years on the CMBR.

    The actually more precise Gaia measurements I referred to have nothing to do with the Hubble constant. This is stellar parallax. We use it to measure the distance to stars in the Milky Way. HD 140283 is in the Milky Way. The age of HD 140283 depends on its luminosity. Read Benchmark stars for Gaia Fundamental properties of the Population II star HD 140283 from interferometric, spectroscopic, and photometric data gets an age of 13.7 ± 0.7 Gyr or 12.2 ± 0.6 Gyr. Note no use of the Hubble constant. The expansion of the universe has no measurable effect in galaxies.
    ETA: I may have given you the impression that this 2015 paper uses Gaia data. The first data release was about a year after this paper. At the title and abstract state, HD 140283 is "one of a list of 34 benchmark stars defined for Gaia astrophysical parameter calibration". The authors use new interferometric and spectroscopic observations.

    An "HD 140283 is measured as being 190LY away from us (minimal redshift)" error. HD 140283 is not a galaxy obeying Hubble's law. We use stellar parallax to measure its distance.

    The Wikipedia page on HD140283 states the star formed between 13.66 and 15.4 billion years ago and that is all we can say about the date of formation. It could have formed 1 minute outside of your dates!
    Last edited by Reality Check; 2020-May-24 at 09:51 PM.

  26. #26
    Join Date
    Aug 2013
    Posts
    586
    Quote Originally Posted by Reality Check View Post
    As applied to galaxies it requires a virial radius and virial mass determined by multiples of the critical overdensity constant per my link to Virial Mass and Radius. https://en.wikipedia.org/wiki/Virial_mass#Virial_radius

    Quote Originally Posted by Reality Check View Post
    The NASA page does not state that we cannot 'measure' (e.g. use the CMBR fluctuations to measure properties of the universe) earlier the CMBR.
    The NASA page states that we don't have the technology yet.

    Quote Originally Posted by Reality Check View Post
    The *actually* more precise Gaia measurements I referred to have nothing to do with the Hubble constant.
    https://www.nasa.gov/feature/goddard...smic-conundrum
    Using Hubble and newly released data from Gaia, Riess’ team measured the present rate of expansion to be 73.5 kilometers (45.6 miles) per second per megaparsec. This means that for every 3.3 million light-years farther away a galaxy is from us, it appears to be moving 73.5 kilometers per second faster. However, the Planck results predict the universe should be expanding today at only 67.0 kilometers (41.6 miles) per second per megaparsec. As the teams’ measurements have become more and more precise, the chasm between them has continued to widen, and is now about four times the size of their combined uncertainty.
    Quote Originally Posted by Reality Check View Post
    An "HD 140283 is measured as being 190LY away from us (minimal redshift)" error. HD 140283 is not a galaxy obeying Hubble's law. We use stellar parallax to measure its distance.
    You used zero and maximum redenning in your original response.

    Quote Originally Posted by Reality Check View Post
    Benchmark stars for Gaia Fundamental properties of the Population II star HD 140283 from interferometric, spectroscopic, and photometric data[/URL] gets an age of 13.7 ± 0.7 Gyr (zero reddening) or 12.2 ± 0.6 Gyr (maximum reddening).

  27. #27
    Join Date
    Aug 2008
    Location
    Wellington, New Zealand
    Posts
    4,415
    [QUOTE=LaurieAG;2513899....[/QUOTE]
    Still irrelevant to my questions.
    IF01: State the conceptual issues that make applying the virial theorem to galaxy clusters and finding that there is matter that is not visible invalid, LaurieAG.
    IF02: Give your sources that state we cannot "'measure' [your quotes] the universe beyond the CMBR limit" or give your own work, LaurieAG
    IF03: Give your sources that detected stars created between ~ 290,00 and 390,000 years ago, LaurieAG

    We still: Measure the effects of inflation creating density fluctuations in the CMBR, have evidence of the cosmic neutrino background radiation exists which was emitted at t ~ 1 second and Big Bang nucleosynthesis happened between t = about 10 seconds to 20 minutes.

    The actually more precise Gaia measurements I referred to have nothing to do with the Hubble constant - they are parallax measurements to stars in this galaxy to determine their distance, luminosity and thus age (see IF02).

    I did use zero and maximum reddening in my original response because that is what the paper says - not your "redshift" implying cosmological redshift which does not exist in the paper.
    Benchmark stars for Gaia Fundamental properties of the Population II star HD 140283 from interferometric, spectroscopic, and photometric data where reddening is not any kind of redshift. It is the reddening of light by dust and gas between us and the star.
    One of the biggest difficulties in determining the bolometric flux is the unknown reddening to the star. For stars that are close enough we can often make the assumption that interstellar extinction is non-existent, or AV = 0.0 mag. However, we also know that the distribution of gas and dust is not homogenous in the Galaxy and even stars that are close may suffer some degree of reddening. In fact, Bond et al. (2013) discussed this point for HD 140283 and remarked that by using HD 140283 as a standard candle and assuming a small degree of reddening yielded a distance to the globular cluster M 92 in much better agreement than without reddening.

  28. #28
    Join Date
    Aug 2013
    Posts
    586
    I have always said in this thread that it is the matter that we cannot see that does not exist in modern physics that is invalid as well as measurements made from technology that doesn't exist yet.

    I posted the link and the actual text of the paper you referred to because you added text that was not in the original in your quote. Also, maximum reddening for a star 190LY away, virtually in our own backyard, seems like more fine tuning to suit a desired answer because it totally skews what 'maximum redness' means on much larger scales by tens of thousands of percent.

    Especially when baryons have been found between galaxies. This paper uses a flat universe with matter and dark energy and their independent measurement is consistent with Cosmic Microwave Background and Big Bang Nucleosynthesis values.
    https://arxiv.org/abs/2005.13161

  29. #29
    Join Date
    Mar 2010
    Location
    United Kingdom
    Posts
    7,279
    Quote Originally Posted by LaurieAG View Post
    This paper uses a flat universe with matter and dark energy and their independent measurement is consistent with Cosmic Microwave Background and Big Bang Nucleosynthesis values.
    https://arxiv.org/abs/2005.13161
    It also uses dark matter. It is about missing baryons, not dark matter. Do the math - it has a universe made of 69% dark energy, 5% baryonic matter. What's missing? It explicitly states several times that it uses the Planck15 cosmology.

  30. #30
    Join Date
    Aug 2008
    Location
    Wellington, New Zealand
    Posts
    4,415
    Quote Originally Posted by LaurieAG View Post
    I posted the link and the actual text of the paper you referred to because you added text that was not in the original in your quote.
    That is wrong. I never misrepresented the paper by adding text to my quote from the paper.
    Quote Originally Posted by Reality Check View Post
    I did use zero and maximum reddening in my original response because that is what the paper says - not your "redshift" implying cosmological redshift which does not exist in the paper.
    Benchmark stars for Gaia Fundamental properties of the Population II star HD 140283 from interferometric, spectroscopic, and photometric data where reddening is not any kind of redshift. It is the reddening of light by dust and gas between us and the star.
    One of the biggest difficulties in determining the bolometric flux is the unknown reddening to the star. For stars that are close enough we can often make the assumption that interstellar extinction is non-existent, or AV = 0.0 mag. However, we also know that the distribution of gas and dust is not homogenous in the Galaxy and even stars that are close may suffer some degree of reddening. In fact, Bond et al. (2013) discussed this point for HD 140283 and remarked that by using HD 140283 as a standard candle and assuming a small degree of reddening yielded a distance to the globular cluster M 92 in much better agreement than without reddening.
    Accusing the authors of making basically faking their data is not good. They applied well known astronomy (the interstellar medium reddens light from stars) and used values of zero and a maximum found in the literature as in my quote.
    This reddening of light from stars in the Milky Way from the interstellar medium in the Milky Way is irrelevant to galaxies. Once again you seem to think that this is something to do with redshift. Redshift is the shift of the entire spectrum to the red from galaxy peculiar velocities or the expanding universe. This reddening is the absorption and emission of starlight by gas and dust of part of the spectrum.

    The missing baryon problem was that we had only detected half of the 4.85% of the universe that is the baryons of visible matter. This was resolved in 2017 by finding more intergalactic matter from the Sunyaev-Zel'dovich effect. The irrelevant to this thread A census of baryons in the Universe from localized fast radio bursts paper is a way of directly detecting the baryons.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •