Moni Bidin, the lead author on a paper detailing the finding in the November 20 issue of The Astrophysical Journal Letters, says that one can always conclude that dark matter escapes detection because it has an exotic nature or unexpected properties. "But failing to detect it in indirect kinematical measurements such as ours," he says, "means finding a way out is harder."

Another dynamical complication comes from the so-called Tully-Fisher relationship, which describes the relation between a galaxy's luminosity and its rotation velocity: the higher the luminosity, the faster a galaxy rotates.

The measured rotation speeds on the outskirts of a spiral galaxy, Milgrom says, depend in "a very strict manner only on the total visible mass of the galaxy." But if the theory of dark matter is correct, then the speed of stars rotating on the galaxy's outskirts should also depend on the shape of the galaxy's dark matter halo.

"Dark matter halos should be lumpy, underinflated football shapes; not spherical," says Stacy McGaugh, an astronomer at the University of Maryland, College Park. "Statistically, that means we should see many [different galactic rotation] velocities for the same luminosity. We don't."

Instead, McGaugh says, the "baryonic tail wags the dark matter dog." In other words, astronomers can predict just what the galactic rotation curves will be from a given galaxy's stellar distribution. McGaugh makes the claim that if dark matter is dominant, observers shouldn't be able to predict the galactic rotation curves by what they see in normal luminous matter.

"Because each dark matter halo should be unique, you should see lots of variation in rotation curves for the same galaxy," he says. "You don't expect the kind of uniformity that we observe in hundreds of galactic rotation curves."

Even if dark matter raises questions on such large galactic scales, particle physicists are hopeful that it will be detected in the lab. If dark matter particles in the sun, for instance, undergo self-annihilation, then such annihilation events could create high-energy neutrinos that would potentially be detectable with ground-based neutrino telescopes.

Then there are detectors, such as the Xenon100 experiment at Italy's National Laboratory in Gran Sasso, built to register direct hits from particulate dark matter. Xenon100 is designed to search for the most favored dark matter particle candidate—the weakly interacting massive particle (WIMP)—by watching for signs that a WIMP has recoiled off an atom in a tank of liquid xenon. A recent analysis of an 11-day observing run in 2009, however, failed to identify any such dark particles, casting doubt on two competing groups' prior claims of possible dark matter signals.

One problem in making such detections is the uncertainty over dark matter's density in the local universe, says Chris Mihos, an astrophysicist at Case Western Reserve University. "Does the dark matter particle not exist," he wonders, "or are we just unlucky in terms of the local dark matter density?"

Current direct detection scenarios include potential dark matter particles with masses between one and 1,000 times the mass of a proton and with interaction "cross-sections" roughly one trillionth the size of a neutron.

After each non-detection, McGaugh says, theorists continually redefine the interaction cross-section of WIMPs to safely undetectable levels. This kind of behavior, he adds, can spark a never-ending game of leapfrog between experimental physicists and theoreticians, allowing them to continue business as usual without ever revising their cosmology.

"There is a lot of misplaced certainty in the dark matter model—a feeling that it's not 'if' we directly detect dark matter, but 'when,'" Mihos says.

Or, as McGaugh puts it, "Once you convince yourself that the universe is full of an invisible substance that only interacts with ordinary matter through gravity, then it is virtually impossible to disabuse yourself of that notion. There is always a way to wiggle out of any observation."

121 Comments

1. 1. scanate 08:05 AM 12/30/10

   Might as yet unknown cosmological dynamics somehow amplify gravity alluding to the existence of Dark Matter?

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2. 2. bertrand_ducharme 08:07 AM 12/30/10

   M. Dorminey, it is refreshing to read an article such as yours. I say so even though I tend to advocate a very peculiar form of dark matter. Everyone may have his pet theory, but they must take into account all the facts.

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3. 3. dbtinc 08:45 AM 12/30/10

   ... or maybe the gravitational constant isn't!

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4. 4. promytius 08:53 AM 12/30/10

   "Dark matter comes about because people unquestionably find mass discrepancies in galaxies and clusters of galaxies" - That, I am sure, is not what he meant. He misspoke; there are not "mass discrepancies" the discrepancies are, in fact, teeny-tiny. What he meant to say, I am sure, was, "Dark matter comes about because people unquestionably find discrepancies in the masses of galaxies and clusters of galaxies."
   Hey, it's my language, I'm the grammar police, and we're here to help you! Clarity above all else. ;)

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5. 5. Peter Fred 09:13 AM 12/30/10

   To quote from the article, "Another dynamical complication comes from the so-called Tully-Fisher relationship, which describes the relation between a galaxy's luminosity and its rotation velocity: the higher the luminosity, the faster a galaxy rotates."
   M. Milgrom and Stacy McGaugh seize upon the empirical Tully-Fisher relation to bolster their view of a modified mass-based gravity theory. But why should mass mediate the gravitational force? What mysterious inherent property does mass have to either attract mass or warp pace?
   On the other hand, could the Tully-Fisher relation mean what is says it means? That is could luminosity of a galaxies be causing the rotation velocity of a galaxy? In other word, could it be the interchanged luminosity between stars, planets, galaxies and clusters that gravitationally binds these bodies? This is an obvious simple, plausible explanation for what causes gravity that has not been seriously explored as say the dark matter hypothesis.
   
   I have placed a test mass between a 1000 W heat source and a ice-filled heat sink. What was observed in four experiments was an average 10% increase of the copper and iron test masses. This is an important result and scientist need to replicate my experiments to rule out the the simple far-reaching possibility that is ubiquitous luminosity that mediates the gravitational force.
   http://vixra.org/abs/0907.0018

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6. 6. Dr. Scott 09:14 AM 12/30/10

   Dear Dr. Bishop: While I am not a proponent of Dark Matter, nor a professional physicist or mathematician, I encountered great difficulties reading your paper.
   
   You have interesting ideas, to be sure. And while some of the current theories you directly attack are obviously flawed, you too casually dismiss any number of observationally verifiable tenets at the core of accepted cosmological physics. The analogies with which you would supplant them may fit some aspects of what we observe, but I submit that they --just like Dark Matter theory-- create unsolvable problems and unanswerable questions in far greater abundance than the current theories. That which is presented without evidence may be dismissed without evidence.
   
   To stay more on-topic with the article, perhaps there is a cosmological physicist out there who can address a multi-part question for me:
   
   First, if gravity is actually an energy force (debatable in M-Theory, I realize) and is propagated in waves, then do competing gravitational waves reinforce, cancel, or otherwise interfere with one another?
   
   Second, if gravity is energy, and energy has mass, then does gravitational energy itself have mass and therefore generate more gravity? And if so, could the density of gravitational fields potentially warp or affect the cosmological constant on a local level so as to produce the effects usually attributed to the elusive and potentially nonexistent "dark matter?"

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7. 7. djl76 09:59 AM 12/30/10

   I have long doubted the existence of "Dark Matter". It is human nature to make up something to explain what we don't understand. Long ago some thought we must have "angered the Gods" and that is why we have no rain, or why we are having a plague. Is that any crazier than to imagine "Dark Matter", something we can't see, can't detect, and yet makes up most of the mass of the universe, in order to explain why the universe doesn't behave the way our theories predict it should? Perhaps the theories, in some fundamental way we don't yet understand, are flawed.

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8. 8. tmt2018 10:03 AM 12/30/10

   It is worth pointing out that the authors of the paper "No Evidence for a Dark Matter DIsk WIthin 4 kpc From the Galactic PLane" (see http://arxiv.org/abs/1011.1289) note that their findings directly contradict the predictions of the most popular modified gravity theory, MOND (Modified Newtonian Dynamics). It predicts a 60% higher disk mass increase than that found.
   
   It is indeed frustrating that incontrovertible evidence for the dark matter particle has still eluded researchers. But the dark matter theory provides a consistent means by which the same galaxies that MOND can explain in terms of certain aspects of their dynamics formed in the first place.
   
   Of course, it may be that the assumed propertes if the dark matter particle (cold, slow moving) have to be modified. Some recent experimental results, both on the ground and in space, indicate that dark matter may be warm, and exist in the form of a sterile neutrino. A recent study of a nearby dwarf galaxy using the Chandra x-ray telescope observed a bump of x-rays at the predicated wavelength that would have been emitted if a sterile neutrino decayed. Experiments at Fermilab have also provided tentative evidence of sterile neutrinos.
   
   The warm dark matter hypothesis should be considered, both for the possible experimental signatures mentioned above, but also because their existence might explain some of the null results of other dark matter searches. Sterile neutrinos wouldn't have weak-scale interactions, and so wouldn't scatter off of target nuclei making up direct detection experiments such as CDMS and XENON100. And they wouldn't annihilate with one another, and so wouldn't produce a gamma ray signature, perhaps explaining why the Fermi satellite hasn't found anything yet.
   

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9. 9. jtdwyer in reply to promytius 10:46 AM 12/30/10

   
   Restated more precisely, astrophysicists unquestionably find _only_ discrepancies between observed gravitational effects (primarily the velocities of objects) and their own _estimations_ of the gravitational effects produced by their _estimations_ of mass, derived primarily on the luminosity apparent in (often only visible light) observations.

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10. 10. jtdwyer in reply to Peter Fred 11:05 AM 12/30/10

    You ask the question: "...why should mass mediate the gravitational force? What mysterious inherent property does mass have to either attract mass or warp [s]pace?"
    
    I'm no physicist, but the mysterious property evidenced by mass is its potential energy, which can be shown to proportionally 'absorb' external energy applied to objects of mass:
    
    - When force is applied to an object of mass, it resists the production of motion. Try pushing your car up a hill.
    
    - Accelerating an object of mass increases its effective mass in addition to producing incremental velocity - the more energy that is applied increases the energy necessary to produce incremental velocity: it is the energy that would have otherwise produced velocity that is applied to increasing the object's effective mass.
    
    I think that Einstein's stated relationship between velocity and the gravitational effect doesn't go quite far enough: IMO, the effect of gravitation _is_ velocity, in the form of an external field of energy generally directed towards the localized center of collective mass. I think that observations of gravitational effects generally support this perspective.

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11. 11. jtdwyer 11:30 AM 12/30/10

    In relation to the critical identification of the Galaxy Rotation Problem that generally established a requirement for some compensatory 'undetected' mass, the accompanying small infrared image of the Andromeda galaxy is highly instructive. Please examine it closely.
    
    It displays the non-visible light generated from the cooler massive clouds of gas, distributed primarily among the galaxy's spiral arms. These massive clouds are not only invisible in the visible light spectrum of early astronomical observations but they are the primary source of new star production, obscuring many stars emitting visible light both enveloped within and laying behind them, in relation to the observer.
    
    Imaged in the visible light spectrum, this galaxy appears, based on its apparent luminosity features, to represent a highly centralized distribution of mass. I suggest this is why Vera Rubin and most astronomers erroneously considered spiral galaxies to operation similarly to the extremely centralized mass Solar system. If they had had access to infrared images of highly distributed mass spiral galaxies they might not have jumped to this erroneous conclusion.
    
    It was the simple, unfounded expectation that spiral galaxies should exhibit the same gravitational characteristics as planetary orbital systems that produced apparent observational discrepancy that seemed to require the presence of undetected mass.

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12. 12. jtdwyer 12:08 PM 12/30/10

    This article presents a nice cursory summation of some of issues surrounding the perceived requirements for dark matter/modified gravity. As a highly experienced information systems analyst, I certainly can't respond to the very many capable physicists who have researched these issues primarily during the past forty years, but from my perspective this whole issue is the product of obviously erroneous analysis of observational data.

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13. 13. jtdwyer in reply to jtdwyer 12:09 PM 12/30/10

    (continued)
    
    Around 1970, Vera Rubin observed the orbital velocities of stars at varying distances from the center of spiral galaxies. To her and her contemporaries' amazement, those velocities did not vary as a function of the stars' distances from the galactic center, as specified by the laws of Planetary Motion derived from observations of the Solar system.
    
    There was no real basis for their expectations, since the only similarities between spiral galaxies and planetary systems is that they primarily consist of a rotating planar disc.
    
    In contrast, planetary systems orbit a dominating central mass (98.8% of total Solar system mass is contained within the Sun), planets are sparsely distributed, bound primarily to the stellar mass. As a result, the further away a planet is from the Sun, the further it is away from most system mass.
    
    Much of spiral galaxies' mass is distributed throughout its planar disc. Stars at the periphery of spiral galaxies primary gravitational influences are the billions of comparable stars and gaseous masses nearest to them, not some oversimplified 'center of mass' located many tens of thousands light years away.
    
    The simple explanation for why the peripheral stars are not expelled from spiral galaxies, despite their seemingly excessive rotational velocity is that, rather than being gravitational bound only to some extremely distant center of mass as presumed by most applications of gravitational analyses, they are much more strongly bound to their many neighboring massive objects in a network of multidirectional gravitational bindings. These bindings produce locally bound structures that can easily resist local centrifugal effects.
    
    There was never any sound, much less proven, basis for expecting the billions of stars in the rotating planar disc of a spiral galaxy to behave like the few planets orbiting our Sun. As a result, there was no need to 'correct' this perceived discrepancy by applying undetected mass or modifying gravitational theory.
    
    I know there is an enormous body of asserted confirming evidence for the existence of dark matter, which I cannot counter effectively here, certainly, but if the observations initially producing its perceived requirements and specification were invalid, shouldn't all asserted confirming evidence be reevaluated?
    

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14. 14. rloldershaw 12:38 PM 12/30/10

    
    
    It is possible that dark matter has already been detected by the various microlensing experiments, and by the research of M. Hawkins and R Schild on quasar and AGN variability.
    
    Their findings suggest that the dark matter is composed of both planetary-mass and stellar mass [~ 0.1 to 1.0 solar masses] MACHOs, and primordial black holes are the most likely candidate if they are right.
    
    RLO
    www.amherst.edu/~rloldershaw
    

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15. 15. zenGeek in reply to jameylynne 01:08 PM 12/30/10

    Jamey, I enjoyed reading your post considerably more than the article. In fact, I created an account just to be able to thank you. Good job.

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16. 16. brodix 01:36 PM 12/30/10

    In very simple terms, what if 'space" expands, but the "universe" does not? The result would be external pressure on the gravitational vortices of collapsing "space," aka, galaxies. This would cause a higher rate of spin on the periphery, as is seen.
    Since expansion and gravity are already inversely proportional, such that large scale space is flat, would the logical conclusion be that there is some sort of cyclical process of collapsing mass and expanding radiation causing the various effects we do see, without recourse to the various ad hoc theories, from inflation to dark energy and matter

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17. 17. carlofab 01:43 PM 12/30/10

    I've always thought of Dark Matter as a temporary door stop to plug a hole in the standard cosmic model. The model works very well except for this annoying problem. And so the door stop allows other researchers doing work that assumes on the standard model to continue for now.
    
    Back in college Qunine's introduction to his logic text addressed the problem of threats to a major theory or model that serves an important role. Problems on the periphery can simply be noted as anomalies. But a threat that strikes at a fundamental of the model must either be dealt with or the model discarded.
    
    And so the Dark Matter door stop saves the theory for now, but is only a temporary patch.
    
    Basically it is the model itself that says Dark Matter must exist. But if this cannot be empirically verified, eventually we must think of something else. The enormity of what is at stake is evidenced by how many cosmologists are hustling to figure this out.
    
    Basically dark matter is being described not by empirical evidence, but by what the model needs to survive. It has no other existence that that.
    
    Some qualified cosmologist please kick me if I'm wrong. This is merely an observation, nothing more.

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18. 18. brodix 01:47 PM 12/30/10

    (Something wrong with the software in this comments section. It freezes when i try to correct...) To continue:
    We recently discovered enormous bubbles of gamma rays around the poles of the Milky Way. Presumably this is the constituent energy of whatever mass fell into the center and is boiling our of the poles, not falling into some bloack hole into another dimension. Possibly it is all the radiation being shed by galaxies which radiates back out across space, causing it to effectively expand, or at least redshift the spectra of light crossing it.
    When gravity bends the path of light, we don't consider the source to actually move. I think a similar optical effect is the cause of redshift, not the actual recession of distant galaxies. That way, dark energy wouldn't be necessary either, since the cosmological constant would be a reverse curvature of the path of light, from that of gravity.
    Remember that the speed of light remains constant. If space actually expanded, wouldn't the speed of light increase proportionally?
    

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19. 19. brodix in reply to carlofab 01:51 PM 12/30/10

    Are suggesting the emperor is naked?
    There is no program for naked emperors, so it cannot be.

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20. 20. bashir59 in reply to jameylynne 02:49 PM 12/30/10

    Your paper of A New Explanation of the Universe is synchronizing with the principles of space physics,further on others whow are going far away in there researches needs to consider this explanation.
    
    Dr. basheer kadhum
    Doctorate in Mech.Eng.

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21. 21. carpefishus 03:06 PM 12/30/10

    Dark matter will be easy to detect once we detect the Ether.

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22. 22. jtdwyer in reply to carlofab 03:21 PM 12/30/10

    Not a cosmologist either but, historically, the consensus recognition of a requirement for 'missing mass' was established solely by the identification of the supposed Galaxy Rotation Problem.
    
    As I understand, that cosmologists found that the proposed compensatory dark matter required by the supposed GRP facilitated a solution to some sticky problems with the standard model of cosmology further added support for the idea of dark matter's existence.
    
    However, dark matter was not nearly enough the standard model of cosmology - it seemed to require the enormous additional mass-energy presumedly provided by the proposed 'dark energy'!
    
    IMO, cosmology's issues may be completely separate from the amount of mass-energy in the observed universe: isn't the amount of mass-energy that is not contained within the _observable_ universe also a solution to those same sticky problems?

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23. 23. jtdwyer 03:45 PM 12/30/10

    The article states:
    "Stars at the very edges of spiral galaxies, for instance, rotate much faster than can be explained by Newtonian gravity alone; the picture makes sense only if astrophysicists either modify gravity itself or invoke additional gravitational acceleration due to an unknown source of mass such as dark matter."
    
    The existence of their characteristic, persistent namesake spiral structures in spiral galaxies is evidence that, in contrast to standard galactic gravitational evaluations, the rotational forces applied to the inner disc is to some degree applied to the entire spiral structure.
    
    Flexibly cohesive spiral structures themselves may consist of loose local and regional gravitational bindings among their component stars and massive clouds rather than the more commonly considered unexplained 'waves' within a fluid of independent masses.
    
    This transference of force can very simply help explain why peripheral stars (gravitationally 'attached' to a spiral structure) rotate at the same velocity as the stars within the inner disc.

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24. 24. wsiebert 04:20 PM 12/30/10

    Is Dark Matter a meta-state of energy between Dark Energy (Black Hole)and matter? If so, it would have many (infinite) values and be impossible to calculate.

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25. 25. Momus 04:32 PM 12/30/10

    @jameylynne > "...This is the old, fifth grade equation, . In two dimensions, that means that as the radius grows, the circumference grows exponentially."
    
    Perhaps it's time to go back to that fifth grade....

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26. 26. QuantaUniverse.com 05:22 PM 12/30/10

    EM forces in plasma labs produce jets with associated x-rays and gamma rays. Black holes are only inferred to exist, with equations using falsely presumed constants proved to vary. light speed slows 5,000 miles per sec in water and was frozen motionless in the lab by magnetic fields. EM forces in our 99.9% plasma universe can freeze light too preventing escape and can explain and do without phony invented dark matter galaxy halos created to keep the obvious EM defined shapes of spiral thin flat galaxies that are composed of magnetized dust and gas having stronger EM forces then gravity that weakens with the square of the distance. the WHIM is ~1 million degrees and constitutes most visible matter in the universe, and is known to be barely visible along the black hole sculpture wall of galaxies, seen as connecting filaments for the cosmic web of imaginary dark matter. the WHIM is denied as evidence and proof that EM forces do not need the enormous extra missing gravity.

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27. 27. jtdwyer in reply to QuantaUniverse.com 05:43 PM 12/30/10

    As I understand, the power or intensity of EM effects also diminish as the inverse square of the distance from their emission source.
    
    Estimating gravitational effects between and object of mass and some attributed center of mass over the vast intragalactic distances of tens of thousands of light years disregards the gravitational effects of billions of much nearer 'neighboring' masses.
    
    The discrepancy between observed gravitational effects and those estimated by astrophysicists are founded in improper estimation methods, not the diminishment of gravitation over distance.

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28. 28. BoRon in reply to jameylynne 06:48 PM 12/30/10

    "...in the time it takes for the ripple to double in size, those two points move apart at over four times the speed of the ripple."
    
    One of your first statements is clearly wrong: the distance between the points, as well as the arc length between them, doubles. Are you thinking of area? I'll try to read more of your "paper" after I read the real comments.

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29. 29. GusGus 07:18 PM 12/30/10

    Not to be nit-picking (well, I guess I am nit-picking), but I learned a long time ago that the convention in astronomy is that "rotation" means an object spinning on its axis, and "revolution" means an object's orbital path. Therefore the paper's references to "rotation" should all be "revolution" except when referring to a galaxy's "rotation". Shouldn't a professed expert in astronomy/astrophysics be aware of this convention? Or has something changed since I learned this convention in the 1950's?

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30. 30. John37309 07:20 PM 12/30/10

    The comments for this article are as interesting as the article itself.
    
    But credit to Bruce Dorminey for excellent science journalism in writing this inspiring article to challenge the dark matter/dark energy problem.
    
    Gentlemen 2011 is the year we will hear the answer to the dark matter/dark energy problem. 2011 is the year when we will have the answer to the problem of understanding gravity in particle physics.
    
    The answer is coming soon gentlemen....... i estimate early January 2011.....and some heads are going to roll!
    
    I need a few days to write the paper.
    John.

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31. 31. carlofab 09:27 PM 12/30/10

    Reply to 21. brodixin .
    
    Sorry brodixin, this dunderhead doesn’t understand. No offense. I’m always embarrassed when I don’t get a joke and someone has to explain it.
    
    * *
    Repley to: 24 - jtdwyerin re: the consensus recognition of a requirement for 'missing mass' was established solely by the identification of the supposed Galaxy Rotation Problem.
    
    * *
    Yes -- and that’s my point. Empirically we find galaxies do not rotate as our cosmic model predicts. For the moment we’ve plugged that hole in the model with a temporary patch called Dark Matter. For now DM is merely a fictional beast based on our standard model’s DESCRIPTION of how galaxies SHOULD rotate.
    
    If we can find empirical evidence dark matter is real, problem solved. If not, we have to decide if we just can’t find it -- or the standard model is fatally flawed.
    
    The standard model works so well it’s easier for now to assume per Occam’s Razor that Dark Matter exists.
    
    But some posters were getting into metaphysical descriptions of the cosmos based on this problem. My comment here is merely to bring us back to the basic problem . Dark Matter is for now merely a fictional description of needs dictated by the standard model.
    
    As Bertrand Russell said, “Just because a man is dying of thirst in the desert doesn’t mean he will find water.”
    
    
    

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32. 32. jtdwyer in reply to carlofab 10:57 PM 12/30/10

    Thanks - well put.
    
    I thought the primary requirement for dark matter in the standard big bang model of cosmology (Lambda-Cold Dark Matter) was to explain how galaxies initially formed from the homogeneous distribution of mass-energy indicated by the observed Cosmic Microwave Background signal emitted in the very early universe. I see now that the Lambda-CDM model does attempt to explain the discrepancy between the observed galactic rotational curves and "how galaxies SHOULD rotate".

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33. 33. Mikek 12:00 AM 12/31/10

    The rubber sheet model gives a clue for another explanation for the higher than expected orbital speeds as we move away from the galactic core. When the rubber sheet is just taunt, and a mass is added the mass makes good size dimple. This would be a high gravitational constant. If the rubber sheet is already under a lot of tension due to the presence of a large mass, and a mass is added the mass makes a small dimple. This would be a low gravitational constant.
    A single star would have a small effect. Like the Pioneer space craft now acting like it has a gravitational constant a tiny bit bigger now that is a very long ways away from the sun. Millions and billions of solar masses should have a really large effect. Small gravitational constant near the galactic core. Larger gravitational constant when at the far edge of the galaxy and beyond.
    It should be possible to get an equation where G is at a maximum value in the great voids far from galactic clusters and grows smaller as get nears to large masses. The equation can be worked out for one large galaxy and then checked to see how it fits the data for another. Such as the Milky Way and Andromeda.
    

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34. 34. tharter in reply to tmt2018 02:01 AM 12/31/10

    "If we can find empirical evidence dark matter is real, problem solved. If not, we have to decide if we just can't find it -- or the standard model is fatally flawed."
    
    You may want to google "Bullet Cluster"...
    
    Not actually criticizing your central point though. CDM is kind of a 'doorstop'. It rightly SHOULD trigger people's bad smell sensor. I think that actually is kind of the point of the article, nobody is really happy with CDM. The problem is every attempt to explain the situation in other ways so far has been clearly fatally flawed. So we have this kind of "phlogiston", CDM, which probably does express something fundamental, but like the medieval phlogiston it isn't exactly what we think it is.
    
    The only real answer is more research. The LHC, etc, will continue to elucidate underlying physics and new and better observations will continue to provide new evidence. At some point we'll find that there is an explanation for all these phenomena we observe that makes sense. We have some ideas of what explanations won't work, but there's a lot of ground left to cover.
    
    Give cosmologists credit though, the obvious explanations have been looked at. jtdwyer for instance considers that galaxies don't behave gravitationally like say solar systems do. Yes, but seriously the people doing this work are well aware of that. Their models aren't THAT simplistic that they model a galaxy like a point mass and make such a basic mistake. Doesn't mean everyone hasn't missed something, but it is going to be tougher to find than that. CDM may well be wrong but it probably isn't completely far off from reality. We'll see though, it sure is interesting :)

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35. 35. jevance in reply to jtdwyer 02:28 AM 12/31/10

    You refer to locally bound structures almost as if you were referring to an atom held in place within a crystal. This is not possible for stars since gravity only attracts but does not repel. An atom, having positive and negative electrical charges, can experience attractive forces to its neighbors because of the positive negative interactions between the atoms yet also experience repulsive forces when the electron shells of neighboring atoms get too close together. Together, these forces can combine so that, no matter which way the atom moves, there is always a restraining force tending to return it to its original position. A star near the periphery of a galaxy is in a much more unstable position where no repulsive gravitational force exists to make it stay in place. An analogy may help to see how gravity influences a star like this. Suppose you walk into New York City. Tall buildings are on every side of you, massing millions of kilograms. According to your reasoning, these buildings would have a much greater effect on you than buildings over in China or in India or England. Using Newton's Law of Universal Gravitation, the force each building in New York exerts on you would be on the order of 1 millionth of a pound, while a similar building in china would exert one million billionth of that because of the much greater distance. However, because the tall buildings in NY surround you in all directions, for the building to the north of you there is a building to the south of you and because of the vector nature of forces, the gravitational forces of the buildings on you would cancel out (or add to zero). A star near the periphery of the galaxy is in the same situation. There is a sphere of stars surrounding it whose gravitational influences add to zero. That leaves the rest of the galaxy to provide the force that does the job of accelerating the star (in the sense of changing its direction). The same is true on Earth--we ignore the gravitational effects of those objects near us, but cannot ignore the combined effects of the buildings in China, England and India, etc and all the rest of the mass of the Earth whose combined influence point to the center of the Earth, many thousands of miles away.

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36. 36. jtdwyer in reply to tharter 05:51 AM 12/31/10

    Seriously, the Galaxy Rotation Problem was initially identified by comparing the Keplerian Rotational Curve to the charted orbital velocity of stars at increasing distances from Andromeda's galactic core, described in Vera Rubin's 1970 research report, "Rotation of the Andromeda Nebula from a Spectroscopic Survey of Emission Regions",
    http://adsabs.harvard.edu/abs/1970ApJ...159..379R
    
    This is essentially equivalent to providing a two body solution for each of the Solar system's planets and the Sun, charting their resulting diminishing 'attractions' as a function of distance.
    
    I haven't conducted a comprehensive survey of all of the many thousand of papers published in the past forty years attempting to model the observed gravitational effects, but applying Newton's law of Universal Gravitation to galactic scale aggregations of billions of massive objects is not fully compliant with its descriptive definition in "The Principia":
    
    "Every point mass attracts every single other point mass by a force pointing along the line intersecting both points. The force is directly proportional to the product of the two masses and inversely proportional to the square of the distance between the point masses."
    
    In my estimation, correctly estimating the gravitational effects imparted to any specific star within the disc of a spiral galaxy should require determining its 'attraction' to every other mass. The result for most stars would be an enormous array of attractions in all directions, dominated by its nearest neighbors (in all directions) - mostly of comparable mass. Only through vector summation of all attractions could any singular directional attraction be reasonably estimated. I strongly suspect that in most cases that net attraction would not be directed to the collective center of galactic mass, up to many tens of thousands of light years away.
    
    In the physical universe, I suggest that omnidirectional gravitational 'attractions' do not 'mathematically' 'cancel out' but each contribute to increasing or diminishing the motion of massive objects. As a result, the array of massive objects present within the discs of spiral galaxies act as a collection of nodally bonded structures rather than the independent fluid mass or two dimensional solid as represented by some more recent attempts to simply describe the behavior of spiral galaxies' discs.
    
    The professional physicists studying this issue are far more knowledgeable than I. However, my assertions should not be summarily dismissed, reasoning that the solution "can't be that simple".

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37. 37. jtdwyer in reply to jevance 06:09 AM 12/31/10

    Perhaps I can better illustrate with a simple example: if you found yourself situated precisely between two equally massive back holes orbiting as a binary pair, would their gravitational effects mathematically cancel out, producing no physical effect? I suggest they would not, that you would be 'spaghettified' by both.
    
    Likewise, I suggest that the innumerable omnidirectional attractions imparted to any given star in the disc of a spiral galaxy tend to generally stabilize that star's position relative to other neighboring objects of mass producing a loosely gravitationally bound persistent structure, for example, the arms of spiral galaxies.

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38. 38. jtdwyer in reply to tharter 06:24 AM 12/31/10

    In reference to the Bullet Cluster, I find it curious that it is the only cited example of merging galaxies exhibiting effects allegedly produced by dark matter.
    
    If all spiral galaxies are enveloped by any form of peripheral 'halo' of dark matter, shouldn't their gravitational effect on 'visible' matter be observed long before the galaxies' merger?
    
    It would seem that the spiral forms of merging galaxies should become deformed or distorted in advance of the approaching peripheral dark matter which purportedly is many time more massive (gravitationally effective) than the rest of the approaching galaxy. There seems to be no observational evidence of this phenomenon...

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39. 39. brodix in reply to carlofab 07:00 AM 12/31/10

    Carlofab,
    Inflation and Dark Energy are also large large fictional beasts to solve discrepancies between observation and theory.
    The discovery of cosmic background radiation was considered conclusive proof of Big Bang Theory, yet BBT couldn't resolve the issue of why it's so smooth. Thus Inflation was added.
    It could simply be that this radiation is the light that has been completely redshifted off the visible spectrum and there is some sort of phase transition 3.7k. Sort of like a "dew point" above which it starts to condense into subatomic matter, eventually to collapse back into gravitational mass, as the opposite side of the cycle of this mass having been broken down, burned up and radiated out across the cosmos in the first place.
    I first began questioning cosmology twenty years ago when I first read that expansion and gravity are inversely proportional. It seemed far more logical that there is some sort of cycle, rather than the coincidence currently assumed. If space is expanding between the galaxies at the same rate it is collapsing into them, where is the overall expansion?
    If the galaxies are not actually moving apart, but are "absorbing" this expansion, there is no need for Dark Energy to explain why the redshift matches a Cosmological Constant and not the original Big Bang.
    Einstein originally proposed the Cosmological Constant to maintain a stable universe, yet now that it has been resurrected to explain redshift, there is no mention of this original purpose.
    They keep finding ever more distant and older galaxies and having to revise how quickly they develop, in order to stay within the age limits of BBT.

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40. 40. jtdwyer in reply to brodix 07:55 AM 12/31/10

    Interesting (I agree: questionable) statement that you read - that expansion and gravity are inversely proportional. If I understand, it would seem that, in that case, the space within galaxies should be collapsing at the same rate that spacetime is expanding, to preserve mass-energy. This seems inconsistent with observational evidence indicating that intragalactic spacetime or local mass-energy density is essentially constant, determined by the mass-energy contained within its localized gravitational domain.
    
    Obviously, even in the hotter, denser early universe, the initial force of expansion exceeded the collective force of gravitation, producing a net universal expansion effect. As spacetime expands, the galactic distances between galaxies generally increase, diminishing the universal (but not local) effectiveness of gravitation.
    
    It seems to me that the original research reporting the acceleration of universal expansion (requiring dark energy) concluded that, since the more distant type Ia Supernovae observed (clustered at distances around 10Glya) were actually more distant than predicted by standard cosmological models (based primarily on galactic redshift) whereas nearer (around 5Glya) observed SNe were consistent with estimated distances, the periphery of the observed universe must be expanding at an accelerating rate.
    
    Seemingly paradoxically, those observations can also be interpreted to indicate that the ancient light emitted by SNe in more distant galaxies exhibit greater rates of expansion than the more recent emissions of SNe in nearer galaxies. In this light, the observational evidence should be considered to indicate that the _earlier_ universe was expanding at a greater rate than now locally observed - evidence that universal expansion is _decelerating_ in compliance with the second law of thermodynamics. In this case, no unidentified dark energy is required.
    
    Oh, surely the resolution of dark energy can't be that simple: I'd appreciate the correct explanation of my presumed error...

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41. 41. jevance in reply to jtdwyer 10:56 AM 12/31/10

    regarding comment 40. Well, if you replace me, in your black hole example, with a General Products hull(Neutron Star by Larry Niven), then the forces would indeed add to zero as far as the movement of the ship were concerned. In any case, your example serves to illustrate the fact that the stronger force determines the motion. In your example, I would split exactly in half and each half would head for the nearest black hole--different parts of me at different accelerations due to the tidal effect. I find it much easier to think of what you describe as stability to be the near cancellations of all the nearby stellar gravitational influences, leaving perhaps a small resultant net force which might produce a small drift velocity of the star away from the orbit it might otherwise follow lacking its immediate neighbors--somewhat akin to Brownian motion. The problem I have with your stability idea is that true stability requires negative feedback. A ball displaced sideways from the bottom of a bowl experiences a restoring force from gravity which acts to pull it back to the bottom (an electromagnetic-gravity interaction). Out in space, the closer two stars get, the stronger the forces trying to make them get closer--a positive feedback effect. Where is the negative feedback in your stability idea?

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42. 42. wsiebert 10:59 AM 12/31/10

    Can Dark Matter be measured or quantified? If Dark Energy is a "potential", having no mass and being in a state of timelessness (word?), and matter having measurable properties that can change with time; Dark Matter can have only some of the properties of matter. But, which properties? Are they constant? Are there enough properties to define it? If Dark Matter is variable, can it even be defined?

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43. 43. nikjabin 12:21 PM 12/31/10

    Jamye, I think you need to go back and review your 5th grade math. The circumference of a circle is determined by Diameter X Pi. Thus the distance is linear on the circumference. To look at straight line distance in Euclidean geometry space from high school algebra using Pythagoras' theorem its a squared + b squared = c squared. So again the distance between two points increase linearly. Vector analysis in higher dimensions yields the same results. Perhaps you confused area and volume. But those increase geometrically and cubically not exponentially.

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44. 44. brodix in reply to jtdwyer 12:29 PM 12/31/10

    jt,
    The more distant sources do appear to be receding at a much higher rate. In fact they appear to recede at close to the speed of light. In BBT is was assumed this was caused by the initial singularity. The problem, which led to the assumption of Dark Energy, was that this rate did not fall off as predicted, but seemed to have an underlaying expansionary effect.
    The point I'm making is that if there is just this Cosmological Constant, then the further light travels, the more the effect compounds on itself and the greater the redshift. Thus the further light travels, the faster its source appears to be receding, until you get to the point that it appears to recede at the speed of light and this creates a horizon line, beyond which visible light cannot travel, but infrared will.
    Which is exactly what we see. Galaxies are redshifted proportional to distance, with no lateral motion of the rates implied by redshift. This creates the impression that we are at the center of the universe, which is why the theory was changed to say it was an expansion OF space, rather than IN space. So that every point appears as the center of its own universe. The problem with this, as I pointed out in the first post, is that there is still a constant speed of light, which means the space defined by lightspeed is stable.
    Another point I raised is that they keep finding ever older galaxies and galaxy structures. Here is a good example:
    http://www.world-science.net/othernews/101125_galaxies.htm
    The infrared light detected could well be that from heavier elements that have been redshifted off the visible spectrum.
    If they ever get the James Webb telescope up, I suspect this issue will only get more problematic.
    

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45. 45. jtdwyer in reply to jevance 01:12 PM 12/31/10

    Again, I admit to having no specific expertise in physics, but in response to the question:
    "Out in space, the closer two stars get, the stronger the forces trying to make them get closer--a positive feedback effect. Where is the negative feedback in your stability idea?"
    
    I don't know that any 'negative' feedback or 'true stability' is necessary to produce, for example, persistent spiral structures.
    
    However, in space, the closer two large masses such as stars get to each other, the faster they orbit one another, very eventually colliding. I read recently of two bodies of mass that so gently and slowly merged that they briefly formed a 'double bubble' body.
    
    I don't fully understand the physics, but while small bodies fall directly into large ones, being directed to the local collective center of mass, large bodies, each with their own local gravitational field, do not fall directly into one another.
    
    In my opinion, there is no 'attractive' force, but rather each object of mass (potential energy) locally contracts kinetic energy permeating space, producing an external field of energy directed to the local center of collective mass, which imparts acceleration to all other objects of mass.
    
    Since two bodies of comparable mass impart similar velocities to each other in opposing directions, rather than falling directly into each other their combined or net velocity is redirected, producing orbital momentum. I think that this perhaps novel description of gravitation better explains observed phenomena than Newton's imaginary 'attractive force', since interactions between large masses do not directly produce collision.
    
    For a network of somewhat stably bound objects of mass, their collective velocity must tend to produce rotation in a way I can't fully describe, similarly to a singular object of mass.
    
    In this, my roughly described personal conception of physical gravitation, perhaps it is the application of the opposingly directed gravitational velocities of massive objects to the production of angular momentum, the effect I think is described in general relativity as the 'curvature of spacetime', that produces the 'negative feedback' you described, preventing collision.
    
    Regardless of whether my conceptual description of physical gravitation is correct or not, that massive objects can form loosely bound, somewhat stable structures is evidenced by the existence of persistent spiral structures in galaxies, in my opinion.

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46. 46. jtdwyer in reply to brodix 02:03 PM 12/31/10

    As I understand, cosmological redshift does not indicate relative velocity - it is the cumulative, direct expansion of the wavelength of light, physically imparted as light traverses increasing distances in expanding spacetime.
    
    Cosmological redshifts do not indicate any velocity, but solely reflects the total expansion of spacetime during the detected light's transmission.
    
    Light that traverses expanding spacetime for a sufficient duration will eventually incur redshift that seems to exceed the speed of light, but it is a cumulative effect incurred over distance.
    
    In this interpretation the amount of redshift presents no particular cosmological problem. The difficulty is that the amount of cumulative redshift detected does _not_ directly indicate the rate of expansion at any particular moment. That can only be inferred by the relationship between redshift and observations of light emitted at varying ages, traversing varying distances.
    
    Presuming a temporally varying homogeneous expansion of universal spacetime, the redshift imparted to light emitted 5Gya is identical to the redshift imparted during the past 5Gys to all light emitted more than 5Gya. The difference between redshift imparted to light emitted 5Gya and light emitted 10Gya is the cumulative effect of spacetime expansion that occurred between 5 billion and 10 billion years ago.
    
    Since the more ancient light from more distant galaxies produced the discrepancy between Ia SNe luminosity based distance estimated and cosmological models that are consistent with more recent light emissions, it is the additional distance traversed by the ancient light emissions that produces the discrepancy for cosmological models.
    
    The excessive expansion exceeding the predictions of cosmological models derived from analyses of ancient light emitted around 10 billion years ago indicated only that the rate of expansion in the early universe (~10Gya) exceeded more recent rates of expansion (~5Gya).
    
    My point is that the SNe calibrated observational data does not indicate an acceleration expansion for the periphery of the observed universe but simply the greater rates of expansion that were prevalent in the earlier universe. Universal expansion is decelerating as previously expected, in accordance with the second law of thermodynamics.

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47. 47. jtdwyer in reply to jtdwyer 02:15 PM 12/31/10

    By the way, the cosmological constant was simply the adjustment knob that was at hand for the researchers to adjust the distances predicted by the cosmological models to match those indicated by the luminosity of ancient SNe Ia light emissions.

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48. 48. brodix in reply to jtdwyer 03:44 PM 12/31/10

    jt,
    
    It does get a bit confusing to unravel. Yes, I realize the distant redshift isn't considered on the periphery, but is the initial expansion.
    The question is how to explain only what we see and not all the layers of modeling applied to it.
    Yes, the CC is an adjustment knob, but what it is supposed to adjust is a balance to the effect of gravity and since gravity contracts, balancing it requires an expansion factor.
    Think in terms of the rubber sheet description of gravity, with the bowling ball deforming the sheet. Since the original sheet is flat space, if you place a weight on it and the overall effect is still flat space, that means the areas which are not weighted down/gravitationally curved inward, balloon outward. Such that between these gravity wells are hills of "expanding space." With the overall effect that they balance out.
    Now if light only travels across that expanding space, which is what it must do, if it succeeds in traveling very great distances, then it is redshifted by that outward expansion and this effect compounds on itself, so that earlier redshift is magnified by the later distance. Thus it's proportional to distance.
    So this is, as you say, not due to any recessional velocity, but the expansion of the space crossed by that light. It is the apparent fact that this overall expansion and not just that crossed by the light, is neutralized by the cumulative effects of gravity, would mean the overall universe is fundamentally flat and stable.
    

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49. 49. jtdwyer in reply to brodix 06:06 PM 12/31/10

    Good - Thanks. I know this is tough to communicate because I am not 'trained' in formal 'physicist speak'. I appreciate your perseverance.
    
    However, it seems to me that, for light traversing intergalactic spacetime, any redshift produced by the gravitational curvature of spacetime is an increasingly localized phenomena. Since the effects of gravitation diminish with distance and expansion affects only intergalactic spacetime increasing intergalactic distances, once intergalactic light leaves its emitting galaxy, how likely is it to encounter significant gravitational effects of other galaxies prior to it detection in our own Milky way? I'd expect that factor's contribution to the redshift of distant light to be a function of universal density, primarily in the early universe, and for light from nearby galaxies, which traverses a high percentage of locally dense intragalactic spacetime.
    
    I have a great deal of difficulty in accepting the rubber sheet model of spacetime, since it is a two dimensional representation of three dimensional space. I envision gravitation to produce a local contraction of three dimensional spacetime that is spherical for typical spherically symmetrical distributions of mass. This model does not readily support the 'balloon surface' representing an overall curvature of spacetime.
    
    I have to consider that it is the rate or velocity of spacetime expansion that physically imparts cosmological redshift to the wavelength of light and that it is the velocity of locally contracted spacetime that produces the much less significant gravitational redshift.
    
    In any case, considering the temporal reduction of mass density, reducing the incidence of gravitationally imparted redshift in an initially extremely dense universe, it might be expected that gravitation's contribution to redshift would be highest for light emitted in the very early universe and diminishing for more recently emitted distant light.
    
    I don't agree that any gravitational redshift would be amplified by the incremental extension to the wavelength of distant light. I think that redshift should be proportional to the expansion of spacetime traversed, _accumulating_ rather than compounding over time and distance.
    
    I think all of this is born out by the fact that the observed more distant SNe's luminosity had diminished more than its redshift indicated that it should have: its ratio of distance/redshift was greater than predicted by standard cosmological models calibrated to more recent light emissions.

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50. 50. jtdwyer in reply to brodix 06:11 PM 12/31/10

    (cont.)
    
    Which brings me back to my issue: how could it possibly be concluded from their SNe observational results that the expansion of the universe is accelerating? I'd really appreciate if you could possibly explain that line of reasoning on the part of apparently a consensus of astrophysicists.
    Thanks in advance...

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51. 51. jtdwyer in reply to jtdwyer 06:22 PM 12/31/10

    (cont.)
    
    I forgot to mention that, if the contribution of gravitationally induced redshift was significant in relation to the redshift imparted by expansion, I'd expect the redshift of light emitted into the dense early universe to be highly redshifted by gravitation in relation to distance traversed.
    
    In contrast, the observational data indicates that the light emitted into the earlier universe incurred less redshift in relation to the distance traversed. Based on this, I suggest that the percentage of distant light's redshift imparted by gravitational curvature is not generally significant in relation to the redshift imparted by universal expansion.

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52. 52. brodix in reply to jtdwyer 08:57 PM 12/31/10

    jt,
    I'm not a physicist either.
    
    I'm not arguing redshift is due to gravitational curvature, but what would have to be an opposing effect. The fact is that cosmology would be much simpler and coherent, if there was another reason for redshift, in which it is proportional to distance. The problem is that goes to the very heart of quantum physics and what is the nature of light and the photon.
    So just as a matter of speculation, let's consider it. A photon is considered an irreducible particle of light with wave like properties, but what if light is an analog emission and photons are the smallest measurable quantity of light; That required to trip an electron to a higher level.
    There are various suppositions required to make this work. For one thing, once an atom begins to become unstable, it's absorption of the required energy speeds up. This way, lots of atoms don't have to "heat up" before one finally "clicks." This would be something of a function of the spectrum, in that the red end would tend to heat up more detectors before one pops, than would radiation higher up the spectrum.
    The point here is that rather than light traveling for billions of years as point particles of energy, it expands out from the source as an analog emission("entangled particles," if you will) and only becomes the photon on point of contact. Given how the photon is described, this isn't that far fetched.
    So how does this affect redshift?
    Think in terms of a water faucet. As you tighten it, the stream gets smaller until it starts dripping. Since the surface tension of water and gravity determine the size of drops of water, they remain the same size, but as the flow continues to be reduced, the time between one drip and the next grows longer.
    
    Now compare this to light. What we get from within the Milky Way and even the closer galaxies is like the running water. It's strong enough for a constant flow of light and so the photon detectors are always clicking. As you get further away though, to the more distant galaxies, this flow of light has become so diffuse that what the detectors are collecting is equivalent to drips of water, as individual photons. As it gets even more diffuse, the photons can't get any smaller, because this is the smallest measurable quantity of light, so the effect is that the time between one photon and the next grows longer.
    

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53. 53. brodix in reply to brodix 08:58 PM 12/31/10

    Now say you are taking a time exposure photograph in order to gather enough light to have a picture. The wave pattern imposed on this process by the time between photons clicking the detector growing longer would cause a redshifted effect. The further the light has to expand from the source, the greater its radius and thus the redshift gets exponentially greater with distance.
    Obviously this is my speculation, but the fact is that a very patchwork cosmology has developed, with everything from Inflation theory to multiverses. What happens when the next anomaly arises? And the next? Do we keep adding patches to the patches? Will we add enough to fill in all the gaps, or is there a point where science says enough is enough and let's go back to the drawing board, completely tear the model apart and see what is wrong.
    
    Ps,
    It's not that the redshift is increasing, but that it isn't decreasing at the rate assumed by Big Bang theory. For people who have spent their lives immersed in this, it amounts to an upward deviation from theory and theory is just about everything. Observations are supposed to support it. So something must be inserted into the theory to align it with observation. This insertion is dark energy. It's a matter of perspective.
    
    

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54. 54. brodix in reply to brodix 09:03 PM 12/31/10

    The further the light has to expand from the source, the greater volume it has to fill, so the light becomes exponentially more diffuse and thus the redshift gets exponentially greater with distance.

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55. 55. jtdwyer in reply to brodix 11:25 PM 12/31/10

    I think I have some somewhat complimentary ideas or conceptions that I've developed independently. There are a few points I'd like to comment on in response to your suggestions, in an attempt to refine them. Again, my terminology is often technically incorrect. First, you suggested:
    "...rather than light traveling for billions of years as point particles of energy, it expands out from the source as an analog emission("entangled particles," if you will) and only becomes the photon on point of contact.
    
    In case you're suggesting the a light waves 'stretch' from their emission source to their eventual detection, consider that the luminosity of a Supernova can suddenly significantly increase, then decrease a few weeks later. I think it's unlikely that those additional photons continue to be 'connected' to an emission source that has already dramatically reduced its EM emissions.
    
    However, I think that not only photons but other particles may alternately manifest in either wave or particle states. Detection of wave properties for any particle seems to occur only in association with self propagation. Energy waves seem to propagate by linearly dispersing through space and time, simultaneously occupying multiple potential locations along a direction of motion.
    
    Conversely, particles seem to be detected only when their propagation energy or momentum has been absorbed by other, more massive particles. Particle properties such as mass seem to be detectable only when the particles are stationary.
    
    The zero rest mass photon seems to manifest only as an energy wave until it's detected by the absorption of its momentum. Particles with mass seem to manifest intermittently as particles then waves, for durations proportional to their identified mass energy.
    
    This particle/wave manifestation may seem to be a simultaneous state determined only by the method of detection applied, but I suspect it is a statistical function of each class of particles, with massive particles more likely to be detected in their particle state manifestation.
    
    I think this characteristic intermittent state manifestation accounts for the seemingly randomly directed 'jiggling' motion of atoms: their self propagating linearly directed characteristic motion is a function of their intermittent wave state manifestation; their stationary particle state configures their kinetic propagation energy as the stationary potential energy of mass while perhaps the particle property of spin redirects subsequent wave state manifestations.

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56. 56. jtdwyer in reply to jtdwyer 12:31 AM 1/1/11

    (cont.)
    
    Just a step further: I suggest that the various classifications of particles with their varying mass and particle state manifestation frequencies were produced as the energy density of the very early universe diminished; initially only high mass particles were produced since the universe was too dense to allow frequent wave state propagation and too hot to allow external reabsorption. Eventually, as energy density reduced, wave state manifestation propagation was uninhibited, allowing emission of photons.
    
    Photons, having no rest mass do not exhibit particle state manifestations until their momentum is externally absorbed by detection.
    
    Now, it seems to me that you may be intermixing the light wave characteristics of frequency and luminosity or intensity. As I understand, energy waves are radially emitted from a point source, dispersing as they radiate in space. For an emission source of a consistent specific intensity or emission luminosity (such as a type Ia SN), its observed luminosity (discounting dispersal by gas clouds, etc.) is a consistent indicator of distance, since light's luminosity or photon detection rate diminishes as the inverse square of its traversal distance.
    
    The frequency of light, I think, is a function of the energy of the emitting material, perhaps corresponding to the number of emitting electrons? Again, I think, cosmological redshift occurs primarily be spacetime between light waves is expanded, physically extending the frequency of waves.
    
    In this view, the luminosity of light or the arrival/detection rate of photons diminishes because light waves are, geometrically, radially dispersed from their emission source. The extension of light's frequency, or redshift, incrementally occurs as a function of the amount that traversed spacetime has expanded.
    
    This means that for a given distance light traverses at a consistent rate of spacetime expansion, the observed luminosity of a light source of consistent emission intensity should diminish at a rate that is consistent with the amount of redshift incurred.
    
    However, this is not what was observed for more ancient and distant SNe light: the diminishment of its observed luminosity indicates that it traversed a distance greater than that predicted by cosmological models calibrated to the distance/redshift of more recent light emissions.

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57. 57. jtdwyer in reply to jtdwyer 12:47 AM 1/1/11

    (cont.)
    
    Restated, the ancient light emissions traversed greater distances without incurring redshift. This should not occur if cosmological redshift and increasing distances traversed by light are both imparted by the expansion of spacetime.
    
    I have one hypothesis that may explain these observational results - I will describe it very briefly:
    
    - The universe is radially expanding from a geometric point of origin. Expansion appears to be omnidirectional as radial dispersal produces a lateral component of expansion.
    
    - The effect of expansion on light waves includes:
    (1) the linear extension of wavelength or redshift for light that is directed in alignment with the prevailing local direction of expansion and
    (2) the curvature of light that is not directed in alignment with the prevailing direction of expansion.
    
    - Light emitted in the dense, early universe is subjected to not only a greater rate of expansion but a greater incidence of radially directed expansion than in the more disperse later universe.
    
    - Light emitted to some extent in opposition to the local direction of radial expansion is curved (due to the resulting curvature of spacetime in the early universe, if you like).
    
    - This curvature occurs in lieu of the linear wavelength expansion or redshift of light, increasing the distance traversed by light in relation to the amount of redshift imparted.
    
    While I'm making some highly speculative cosmological presumptions, I think this hypothesis can account for the observed luminosity and redhshift characteristics of SNe calibrated distant light emitted into the conditions of the early universe without inferring an acceleration of universal expansion requiring some unidentified proxy of dark energy.

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58. 58. Arthur Sanchez 01:37 AM 1/1/11

    If one bases one's theories on "relativity", then one's conclusions and calculations will always be "relative" or subject to change. However, all science becomes perfect when one's theories are based on "reality" as opposed to "relativity", then one's conclusions and calculations will become "absolute" as opposed to "relative" and not be subject to change.
    
    You see, scientists cannot seem to find the source of the existence of matter, hence their fumbling in the dark until they bump into something and then try to explain the bump like the "dark matter" bump. But attempting to explain the relative using the relative is like a "wave" trying to explain another "wave". An absolute point can never be attained.
    
    Those who say that the calculations regarding the theory of gravity need to be modified are closer to the truth because an illusive "dark matter" need not exist to explain the calculation problems of existing matter in relation to mass.
    
    

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59. 59. whatsup 04:57 AM 1/1/11

    The mond pages
    
    http://www.astro.umd.edu/~ssm/mond/stakes.html
    http://www.astro.umd.edu/~ssm/mond/blunder.html
    http://www.astro.umd.edu/~ssm/mond/mondvsDM.html
    
    The history of science is a decision tree. Vertices appear where we must take one or another branching. Sometimes, we take the wrong road for the right reasons.
    
    A good example is the geocentric vs. heliocentric cosmology. The ancient Greeks knew that in many ways it made more sense for the earth to revolve around the sun than vice-versa. Yet they were very clever. Ptolemy and others tested for the signature of the earth's orbit in the seasonal wobbling in the positions of stars, or parallax. If the earth is moving around the sun, nearby stars should appear to move on the sky as the earth moves from one side of the sun to the other. Try blinking back and forth between your left and right eyes to see this effect, noting how nearby objects appear to move relative to distant ones.
    
    Problem is, Ptolemy did not find the parallax. Quite reasonably, he inferred that the earth stayed put. We know now that this was the wrong branch to choose, but it persisted as the standard world view for many centuries. It turns out that even the nearest stars are so distant that their angular parallax is tiny (the angle of parallax is inversely proportional to distance). Precision sufficient for measuring the parallax was not achieved until the 19th century, by which time astronomers were already convinced it must happen.
    
    Ptolemy was probably aware of this possibility, though it must have seemed quite unreasonable to conjecture at that time that the stars could be so very remote. The fact was that parallax was not observed. Either the earth did not move, or the stars were ridiculously distant. Which sounds more reasonable to you?
    
    So, science took the wrong branch. Once this happened, sociology kicked in. Generation after generation of intelligent scholars confirmed the lack of parallax until the opposing branch seemed so unlikely that it became heretical to even discuss. It is very hard to reverse back up the decision tree and re-assess what seems to be such a firm conclusion. It took the Copernican revolution to return to that ancient decision branch and try the other one.
    
    Cosmology today faces a similar need to take a few steps back on the decision tree. The problem now is the issue of the mass discrepancy, typically attributed to dark matter. When it first became apparent that things didn't add up when one applied the usual Law of Gravity to the observed dynamics of galaxies, there was a choice. Either lots of matter is present which happens to be dark, or the Law of Gravity has to be amended. Which sounds more reasonable to you?
    Having traveled down the road dictated by the Dark Matter decision branch, cosmologists find themselves trapped in a web of circular logic entirely analogous to the famous Ptolemaic epicycles. Not many of them realize it yet, much less admit that this is what is going on. But if you take a few steps back up the decision branch, you find a few attempts to alter the equations of gravity. Most of these failed almost immediately, encouraging cosmologists down the dark matter path just as Ptolemy wisely chose a geocentric cosmology. However, one of these theories is not only consistent with the data, it actually predicts many important new results. This theory is known as MOND (MOdified Newtonian Dynamics). It was introduced in 1983 by Moti Milgrom of the Weizmann Institute in Israel
    .
    MOND accurately describes the effective force law in galaxies based only on the observed stars and gas. What this means is unclear, but it clearly means something! It is conceivable that dark and luminous matter somehow interact to mimic the behavior stipulated by MOND. This is not expected, and requires a lot of epicyclic thinking to arrange. The more straightforward interpretation is that MOND is correct, and we took the wrong branch of the decision tree back in the '70s.
    MOND has dire implications for much modern cosmological thought which has developed symbiotically with dark matter. As yet, no one has succeeded in writing down a theory which encompasses both MOND and General Relativity. This leaves open many questions in cosmology that were thought to be solved, such as the expansion history of the universe. There is nothing a scientist hates to do more than unlearn what was thought to be well established. It is this sociological phenomenon that makes it so difficult to climb back up the decision tree to the faulty branching.
    
    Once one returns and takes the correct branch, the way forward is not necessarily obvious. The host of questions which had been assigned seemingly reasonable explanations along the faulty branch must be addressed anew. And there will always be those incapable of surrendering the old world view irrespective of the evidence.
    
    In my opinion, the new successes of MOND can not occur by accident. They are a strong sign that we are barking up the wrong tree with dark matter. A grander theory encompassing both MOND and General Relativity must exist, even if no one has as yet been clever enough to figure it out (few have tried).
    These all combine to make life as a cosmologist interesting. Sometimes it is exciting. Often it is frustrating. Most of the time, ``interesting'' takes on the meaning implied by the old Chinese curse:
    
    MAY YOU LIVE IN INTERESTING TIMES
    
    Like it or not, we do.
    
    http://www.astro.umd.edu/~ssm/mond/CMB1.html
    http://www.astro.umd.edu/~ssm/mond/index.html
    
    

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60. 60. jtdwyer in reply to whatsup 07:38 AM 1/1/11

    Interesting background, but why did Vera Rubin and her contemporaries expect that the laws of Planetary Motion, specifically the Keplerian rotational curve, derived from observations of the highly centralized mass Solar system, to fit the highly distributed mass configurations of spiral galaxies?
    
    That they don't is no reason to imagine additional mass or to modify gravitational theory to force galaxies to behave like simple planetary orbital systems. I suggest that you please read my earlier comments, beginning with #13 and #14.

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61. 61. Peter Fred 10:02 AM 1/1/11

    @Whatsup
    I agree that we have a situation today with the "extragalactic catastrophe" that is very similar to to what occurred with the Aristotelian geocentric theory. But MOND is a weak compromise comparable to Tycho Brahe's idea that was popular at the time of Galileo. Copernicus came up with a foundational change it was a foundational change that eventually won out. Geocentrism was replaced with heliocentrism.
    
    With the mass-based gravity theories of Newton and Einstein there is similarly a simple, plausible foundational change that can be made. Instead of thinking that it is the mass of the earth that attracts the moon one can consider that it is heat of the earth that attracts the moon. In other words one can consider that it is not the mass of stars, galaxies and clusters that gravitationally binds these bodies but rather the luminosity emanating from them that does the gravitational binding. For five table-top experiments showing the "spreading infrared radiation" is gravitationally attractive and gravity paper based on this experimental observation go to http://vixra.org/abs/0907.0018

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62. 62. jtdwyer in reply to Peter Fred 12:49 PM 1/1/11

    Sorry, but in that case I don't understand why the moon would continue its orbit as it passed around to Earth's 'dark' side. It would seem that it's orbit would at least deteriorate without the Sun's light reflected from Earth's surface.
    
    Moreover, in the outer Solar system the effects of gravitation do seem to be proportionate to mass as moons orbit massive but darker planets...

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63. 63. brodix 12:58 PM 1/1/11

    jt,
    My knuledge base isn't great, but I understand the difference between luminosity and frequency. I was just proposing a possible mechanism for redshifting the frequency, since I do not agree with the fundamental premise of an expanding, finite universe and find the many patches added to maintain it as proof in themselves of a deeper problem with the model.
    Another problem I have is with four dimensional spacetime, since I think we are looking at time backwards. We think of it as the point of the present moving from past events to future ones, but the physical reality is that the changing configuration of what is present turns future possibilities into past circumstance. We don't travel the fourth dimension from yesterday to tomorrow. Tomorrow becomes yesterday because the earth rotates. Time is an effect of motion, not the basis for it. So it does make sense that all clock record their own time, but the fact that one more run faster than a similar clock, under different conditions doesn't means they travel different paths through the spacetime continuum, but simply that their atomic activity has different "metabolic rates."
    If we view time as simply an emergent effect of motion, then the particles cannot be isolated from its motion, since there is no dimensionless point in time. It would be like taking a picture with the shutter speed set at zero. So, in terms of the uncertainty principle, there is no absolute position.
    Also, if time is the collapse of future probabilities into past circumstance, rather than a progression from past to future, the idea of multiworlds is dispensed with.
    

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64. 64. brodix 01:10 PM 1/1/11

    Time then, is similar to temperature, rather than space, which then opens up the question of space. Since it has no physical manifestation outside of what occupies it, I don't think it is really curved, expanded, bounded, etc. Because if this, it does have two attributes; It is in equilibrium, ie. fundamentally flat and it is infinite.
    When the argument is make that it is curved because the path of light is bent by gravity, there still has to be that geometric straight line to compare this curvature to, otherwise there would be no way to calculate the curvature. Equally, when we say it is expanding because two pints of measurement are moving apart, they are moving apart according to stable units of measurement, or we couldn't detect this increasing distance. If the ruler is being stretched, it always still twelve inches long. The Doppler effect is due to varying distance in stable space. The train is putting space that was in front of it, behind it, not creating new space.
    Similarly the BBT has problems with a basic geometric expansion because we appear at the exact center of the universe. This was amended to say that space itself is expanding, but the problem with that is that we still have a stable speed of light and that requires a stable dimension of space, ie. flat. Otherwise, if two sources are x lightyears apart and space actually expanded, they would always be x lightyears apart, much like the ruler being stretched.
    It makes much more sense if the is an optical cause for redshift. Then it would be perfectly logical that it is proportional to distance.
    I realize I'm getting a bit off track here, but I think we will find physics will become ever more of an incomprehensible knot and in need of a reset. In a few more years, this view could even go mainstream, since even those at the apex of the discipline are losing faith in many prevailing theories.

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65. 65. jtdwyer in reply to brodix 01:55 PM 1/1/11

    Sorry if I misunderstood your earlier comments about redshift and dispersal - my understanding is limited.
    
    I do agree with your comments regard the curvature of spacetime. In my view Einstein may or may not have understood that it was not spacetime that physically curved, but he had to convince astronomers of the day to perform his eclipse experiment and they certainly _knew_ that light does not curve!
    
    In my view, the 'curvature' attributed to spacetime better applies to the path of matter in linear motion traversing the external gravitational velocity field of massive objects. It is the velocity directed to the center of spherically symmetrical massive objects that is added to the linearly directed velocity of light, for example, that produces the curved path of light.
    
    While I certainly realize that General Relativity's equations for estimating the effects of gravitation are extremely useful (when correctly applied) and that its system of 'curved' spacetime coordinates can be highly effective, I do not think GR's description of the forces producing those effects reasonably represent physical reality.
    
    Thanks for your interesting discussion!

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66. 66. brodix 02:20 PM 1/1/11

    jt,
    Here is an interesting interview with Carver Mead, one of the foundational figures in Silicon Valley, on a book he wrote some years ago about his thoughts on the problems in physics;
    http://freespace.virgin.net/ch.thompson1/People/CarverMead.htm

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67. 67. jtdwyer in reply to brodix 07:06 PM 1/1/11

    Thanks! I dislike reading, especially chit chat, but Mead did express some very complimentary views. A very apropos selection. You might get me at rocketmail com, since we're already way off topic here...
    
    That it's called particle physics does infer that it's a little myopic, doesn't it?
    
    Re. quantum physics: in my experience, statistics is most useful for those who are uncertain, having no relevant knowledge. As I mentioned previously, I think that matter intermittently manifest at specific frequencies as propagating kinetic energy waves and stationary potential energy particles of mass, conserving propagation/mass energy. The zero mass photon is the exception, manifesting only as a wave until its momentum is absorbed upon detection.
    
    Perhaps I'm wrong, but when Mead said: "You can make an electron that's ten feet across..." and "People regularly do experiments with neutrons that are a foot across," I think he was referring to waves that are that _long_.
    
    Re. quantum entanglement, I have some ideas that I'll try to explain briefly:
    - The emission of a single or quantum particle is better described as en energy wave emission of precise duration such that only a single particle can be detected though absorption of the wave's momentum.
    - Directing a wave to a slotted gates separated precisely so that portions of the wave can simultaneously pass through each slot produces a singular wave that is separated into two independently directed wavefronts but still physically connected behind the gate.
    - Each wavefront can be independently detected as a quantum particle by absorption of its momentum; both exhibit the characteristics of the singular wave.
    - The only probabilistic uncertainty is externally imposed by the experimental conditions.

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68. 68. brodix in reply to jtdwyer 10:59 PM 1/1/11

    There is a definite dualism to nature. We see the opposite sides, but when we try seeing the whole, it becomes some running in circles process. It is fundamentally dynamic, but our concepts are static.
    Happy New Year. It's going to spin on by like all the others and hope we don't get spun off in the process.

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69. 69. brodix in reply to jtdwyer 06:34 AM 1/2/11

    You are right, this is getting off topic, but conversations in physics seem to involve wandering in ever larger circles these days. Mostly I discuss it at fqxi.org. They are pretty lenient on those of us who might be considered cranks, but there are some interesting conversations on occasion.
    Personally I've been banned from physicsforums for the point that time is the future becoming the past and at Cosmic Variance for the same issue, as well as arguing against Big Bang Theory.

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70. 70. jimhenson 06:56 AM 1/2/11

    Phony Dark Matter does not react with light nor visible matter. Inventing huge extra gravity halo locations around obvious EM defined galaxy spiral shapes and rotation curves, the outdated big-bang model is kept alive under artificial life support. Gravitons particles have never been proven nor seen either, to invent dark matter particles invisible huge extra 90% gravity instead of acknowledging EM forces in plasma is misleading science and society.
    http://quantauniverse.com

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71. 71. jtdwyer 11:48 AM 1/2/11

    For a brief but thorough summary of how and why the perceived requirement for an enormous amount of undetected mass in spiral galaxies became established please refer to:
    http://en.wikipedia.org/wiki/Galaxy_rotation_problem
    
    It explains that astronomers in the 1960s were surprised to discover that spiral galaxies do not comply with the empirically developed laws of Planetary Motion. In particular, spiral galaxies did not conform with the law's specified rotation curve which states that rotational velocity should diminish as a function of distance from the galactic center.
    
    Expecting that stars in the discs of spiral galaxies should orbit the 'galactic bulge' like planets orbit the Sun, it was found that they instead rotated at the higher velocity expected only for stars within the inner disc. Simulation models based on planetary system motions indicated that peripheral stars rotating at such high velocities should be expelled from the galaxy by centrifugal forces.
    
    As a result of these discoveries, it seemed that either an enormous amount of additional undetectable mass must be present or that gravity worked differently for very large scale structures. These perceptions led to the development of the dark matter hypothesis and to alternative theories of gravitation such as MOND.
    
    Preferring not to modify well established theories of gravitation, physicists generally accepted the dark matter hypothesis.
    
    However, since the laws of planetary motion apply only to the extremely centralized mass configurations of sparse planetary systems (98.8% of total Solar system mass lies within the Sun), there was never any established theoretical basis for expecting the highly distributed mass configurations of spiral galaxies to behave in the expected manor.
    
    If one considers the gravitational forces most affecting planets in the Solar system, they are produced by the Sun's mass. In contrast, if one considers the gravitational forces affecting a star in the periphery of a spiral galaxy disc, it is most certainly produced by any massive gas clouds and the many other comparably massive stars nearest the subject. Since the effect of gravitation diminishes rapidly with distance, the effect of mass located near the galactic center many tens of thousands of light years away is highly diminished.
    
    To this highly experienced information analyst, this frustrating problem is obviously the product of a fundamentally simple misconception that occurred more than forty years ago.

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72. 72. mo98 11:46 AM 1/4/11

    I was encouraged to read that a more successful alternative is the modified gravity (MOG) theory of Moffat such as scalar-tensor-vector gravity (STVG). A number of questions or points follow:
    1. Why is there no observed chromatic abberation of objects having differing frequencies of radiation in the electromagnetic spectrum subject to gravitational lensing?
    2. Why should the influence of sparse gravity between galaxies and at their edges be infinitely divisible?
    3. Why need interatomic space be grainy if optics fills the void with quantum effects when displacing crystalline solids ever so slightly with gravity?
    4. If there is a finite amount of gravity tensors proportionate to any mass, what happens when there is not enough of them to go around to fit the laws of attraction between masses?
    5. On a "small scale" gravitational tensors overlap and tides on the earths oceans slow the orbit of the moon.
    6. On a large scale resulting from nova and greater explosions, why cannot there be pockets of gravity tensors that, like muscle tissue, stretch till they divide to maintain their ordered influence between all other significant masses or reference frames?
    
    

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73. 73. jtdwyer in reply to mo98 03:36 PM 1/4/11

    While equations can be modified to mimic observational results, they are still applied to a simplified centristic evaluation of vastly disperse complex distributions of mass and their associated gravitational effects.
    
    What physical manifestation explains and justifies the modification to gravitational equations?
    
    In short, what is the physical theoretical basis for Moffat's MOG/STVG (both terms refer to the same method) or any other analytical simulation of observational results? What physical effects explain the modifications required to produce the desired results?
    
    I suggest that modified gravity theories are merely unfounded mathematical contrivances, as is the proposed dark matter, intended to produce the observed results through convenient computational 'fudge factors', analogous to placing a finger on the scale.
    
    As explained in my prior comment above, the fundamental problem is that the methods developed to estimate gravitational effects for the discrete, centralized configurations of mass that prevail at stellar scales and below are being force-fit to applications of vast aggregations of innumerable discrete massive objects.
    
    If spiral galaxies only consisted of sparse planetary masses revolved around a single enormous star or black hole containing most of the system's mass, physically producing most of the systems gravitational effects, just like the Solar system, we wouldn't be having these problems - the laws of Planetary Motion would correctly apply.
    
    Unfortunately, the actual complex, disperse configurations of galactic scale masses and their gravitational effects are much more difficult to mathematically represent. This is not evidence that gravitational effects produced by identical distributions of mass varies with scale.

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74. 74. iward 04:37 PM 1/4/11

    If "the higher the luminosity, the faster a galaxy rotates", then "dark energy" might actually be, in part, "light energy". Since m=E/c^2, light itself may account for some of the missing mass.

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75. 75. jtdwyer in reply to iward 06:00 PM 1/4/11

    I think the statistical relationship between luminosity and mass is only indirectly causal in nature: Much of galactic mass (especially the central 'galactic core' in the visible light spectrum) is composed of stars; the luminosity of stars is most often caused by their their mass.
    
    However, as I understand, the planar disc of spiral galaxies, especially, contains enormous opaque clouds of gaseous masses. Those massive clouds are the birthplace of new stars. Many short lived massive stars are contained within and around these massive clouds which obscure them. As a result, the reduced luminosity of spiral galaxy discs in relation to their central regions can skew astronomer's estimations of mass based on reduced luminosity.
    
    As I understand, these obscuring gaseous clouds are most prevalent in spiral galaxies which, using standard methods of gravitational estimation, indicate to astrophysicists the greatest requirement for compensatory dark matter.
    
    The identified missing mass is inferred by astronomers from the consistent rotational velocity of stars within the galactic discs of spiral galaxies. This contrasts with the diminishing rotational velocities of planets around a star.
    
    This phenomena of spiral galaxies can be easily explained by local gravitational effects among the stellar ant other masses distributed throughout the discs of spiral galaxies. Centripetal (rotational) forces applied to the stars of the inner disc are transmitted through locally bound structures extending to the periphery of the disc, producing consistent rotation throughout the disc. There should be no compensatory 'missing' mass or modified gravitational effects necessary to produce the observed rotational characteristics.

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76. 76. iward in reply to jtdwyer 10:01 AM 1/5/11

    I'm starting to think that a lot of guys became techies because they had difficulty writing essays in plain English.lol. Anyway, I was just trying to suggest that the total mass of photons in galaxies should be taken into account in the Galaxy Rotation Problem. This doesn't conflict with your theory, which you seem to need everyone to know about.

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77. 77. mike cook 10:27 AM 1/5/11

    I continue to be struck by the relation between the supermassive dark hole at the center of most galaxies and the rotational speed (sigma)of the respective galaxy's disk. A BH is just full of we know-not-what and galaxies appear to have a halo of we know-not-what.
    
    If these two regions are entangled from early days or are still in communication somehow via unknown forces we could consolidate our unknown factors.
    
    I just read Lisa Randall's book WARPED PASSAGES:UNRAVELING THE MYSTERIES OF THE UNIVERSE'S HIDDEN DIMENSIONS. It occurs to me that points which are a hundred thousand light years distant in our common three spatial dimensions could be the exact same point in seven more curled up physical dimensions.
    
    Randall also talks about the effects of other dimensions leaking over, or our gravity leaking out, all of which could cause the gravitational "constant" to maybe not be so constant from place to place. She uses the phrase locally local gravity.
    
    

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78. 78. jtdwyer in reply to iward 02:07 PM 1/5/11

    Yeah, you found me out!
    
    Plain English is not very precise and is subject to misinterpretation. While my attempts at more precise description may be more difficult to understand, hopefully, it's less subject to unintended interpretations...

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79. 79. jtdwyer in reply to mike cook 02:40 PM 1/5/11

    In my opinion, the 'sigma' mystery has a extremely simple explanation: since the Supermassive Black Hole at the center of spiral galaxies has a consistent value of 0.5% of total galactic mass and total galactic mass is directly related to 'sigma' (peripheral rotational velocity), the gravitational effect (mass) of the SBH _must_ be statistically correlated to peripheral rotational velocity even though the gravitational effects of the central supermassive black hole cannot be 'felt' by the galaxy's peripheral stars. No direct causal relationship between SBH mass and peripheral rotational velocity is necessary to produce this statistical relationship.
    
    However, as I explain, rotational velocity is the product of the gravitational effect of total galactic mass applied to the disc. The local structural bindings among stars within the galactic disc allows the transmission of the centripetal force in effect at the inner disc throughout the disc and to its peripheral stars.
    
    Unlike the the weak gravitational effects among relatively disperse Solar system planets, the stars within spiral galaxies' discs are self gravitating: they are primarily bound with their neighboring masses.
    
    The much greater mystery to me is: why is the sumpermassive black hole of spiral galaxies consistently 0.5% of total galactic mass? Discovering the physical process responsible for producing this phenomenon could teach us much about the true physical nature of gravitation.

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80. 80. Grantwo 09:20 PM 1/5/11

    What if dark matter can only be detected while it still exists. Light traveling across space exists as matter that has left an origin regardless of whether it's origin is still in existence or not. Maybe it is possible that dark matter travels faster than the speed of light?

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81. 81. Laird Wilcox 11:14 PM 1/5/11

    Dark matter has always seemed improbable to me, and the case for it was on the order of "The absense of evidence is not evidence of absence," to quote Donald Rumsfeld. What I suspect dark matter will turn out to be is (1) Trillions of brown dwarfs or large planets throughout the galaxies, or (2) a supposition based on bad or incomplete data, or (3) both. Dark matter and dark energy are probably just plain old ordinary matter and energy that we simply haven't found the source for yet. The human tendency to invent explanations for things we don't understand is very strong.

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82. 82. Jan Jitso 05:06 AM 1/6/11

    Scientific American should bring an article on the new theory of Vasily Yanchilin in his book "The Quantum Theory of Gravitation"" (2003), as such will help much to get better discussion. This Russian scientist is the first to present a qualitative theory in which gravity is explained in harmony with quantum mechanics. He does so in his book with good argumentation and solid mathematics. The new theory rejects negative energy and Yanchilin suggests that light (or old light, changed fotons?) may be responsible for (a big part of) dark matter.

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83. 83. jtdwyer in reply to Jan Jitso 06:26 AM 1/6/11

    So Vasily Yanchilin must explain the mechanical process that converts old photons to another type of yet unidentified particle, losing their characteristic property of self-propagation and acquiring extremely high rest mass? Since the photons of the CMB are thought to have been the first photons to escape the hot plasma early universe, redshifted from infrared to microwave frequencies, how old do these dark matter photons have to be?

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84. 84. LaurieS 09:15 AM 1/6/11

    "Show me"

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85. 85. verdai 05:53 PM 1/6/11

    may be nothing except Spirit.
    in the void.

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86. 86. debu 10:34 PM 1/6/11

    DURGADAS DATTA published some outstanding papers in ASTRONOMY.NET in year 2002 . The papers are --MISJUDGEMENTS BY NEWTON. ---ETHER=GRAVITY=DARK ENERGY THEORY OF GRAVITOETHERTONS ,---BALLOON INSIDE BALLOON THEORY OF MATTER AND ANTIMATTER UNIVERSE ON OPPOSITE ENTROPY PATH PRODUCING DARK ENERGY OR GRAVITOETHERTONS CONSISTING OF FIVE GOD PARTICLES AT COMMON BOUNDARY BY ANNIHILATION AND INJECTED INTO OUR UNIVERSE AS DARK ENERGY FOR ALL LAWS AND GRAVITY AND ACCELERATING UNIVERSE ETCETC. HE ALSO SAID THAT NEWTONS EQUATION MODIFIED F=P.G.M.m/R.R WHERE P IS PERMEABILITY OF NON UNIFORM UNIVERSE IN GRAVITOETHERTON SOUP SWIRLING AND WHIRLING. IF YOU TAKE THESE APPROACH OF DURGADAS DATTA THEN SOON LHC-GENEVA WILL DISCOVER FIVE GOD PARTICLES AND MYSTRY OF DARK MATTER=DARK ENERGY=ETHER=GRAVITOETHERTONS WILL BE SOLVED IN OUR NON UNIFORM UNIVERSE OF FILELD DENSITY. NEWTON AND EINSTEIN BOTH WILL BE MODIFIED ACCORDINGLY.

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87. 87. johnhei 05:24 AM 1/7/11

    The Carmeli-Hartnett cosmological model based on cosmological relativity not only eliminates the problems with the Big-Bang model, but also eliminates the need for dark matter and energy.

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88. 88. Quinn the Eskimo 10:32 PM 1/7/11

    Beyond the incontrovertible fact that: Nothing unreal exists -- Looking at you string fanatics -- there is Dark Matter. Or not.
    
    We're still in the dark. We're not ready.
    
    After reading 90-some comments I'm convinced. Somewhere someone is laughing at us.

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89. 89. Postman1 in reply to Quinn the Eskimo 10:03 AM 1/8/11

    I have been, but I am sure that's not what you meant.

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90. 90. jtdwyer 03:49 PM 1/8/11

    To clarify, in the 1970s Vera Rubin led a group of astronomers in a series of observations of the rotational characteristics of principally spiral galaxies. Their principal finding was that galaxies unexpectedly did not comply with the rotational curves empirically established for planetary orbital systems by Kepler and later Newton in the laws of Planetary Motion.
    
    It was initially determined that some additional undetected and unidentified form of mass could, using standard methods of gravitational evaluation, account for the much greater than expected peripheral orbital velocities observed. However, there was no theoretical support in the standard model of particle physics for any form of matter that could meet the properties required of dark matter.
    
    As I understand, a small group of theoretical physicists, convinced by the observational data but dissatisfied with the proposed dark matter solution, attempted to develop modified gravitational equations that varied in their effects for larger scales of mass configurations. To my knowledge, there has never been established any theoretical basis for these variable gravitational equations.

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91. 91. jtdwyer in reply to jtdwyer 03:50 PM 1/8/11

    (cont.)
    
    The gravitational evaluation methods used in identifying the presumed requirement for galactic dark matter can be found in a 1980 paper by Vera Rubin, et al, "Rotational properties of 21 SC galaxies with a large range of luminosities and radii, from NGC 4605 /R = 4kpc/ to UGC 2885 /R = 122 kpc/",
    http://adsabs.harvard.edu/abs/1980ApJ...238..471R
    
    Please pay particular attention to page 479 for a discussion of how galactic rotational curves exhibit a "lack of Keplerian decreasing velocities [as stars' distances from the galactic center increase]. This was the principal, if not only, evidence requiring compensatory galactic mass.
    
    On page 485, section "VIII DISCUSSIONS AND CONCLUSIONS"; conclusion 1 states: "The conclusion is inescapable that non-luminous matter exists beyond the luminous galaxy."

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92. 92. jtdwyer 04:02 PM 1/8/11

    I am by no means the first to be dissatisfied with the dark matter solution to the observational discrepancy with expected galactic rotational characteristics, including those who prefer to modify gravity. I am not even the first to have identified shortcomings in methods applied to the gravitational evaluation of spiral galaxies.
    
    In "General Relativity Resolves Galactic Rotation Without Exotic Dark Matter", 2005, F. I. Cooperstock and S. Tieu state that:
    "...insufficient attention has been paid to the fact that the stars that compose the galaxies are essentially in motion under gravity alone (“gravitationally bound”)."
    http://arxiv.org/abs/astro-ph/0507619v1
    
    However, their model intended to represent the discs of spiral galaxies "as a stationary axially symmetric pressure-free fluid" but was criticized as 'unphysical' for also containing a thin separate disc.
    
    In "Newtonian mechanics & gravity fully model disk galaxy rotation curves without dark matter", presented at the For IAU Symposium 254 on Galaxy Disk in Cosmological Context, 9-14 June 2008, Copenhagen, Denmark, Dilip G. Banhatti presents the gravitational estimation methods developed from about 2000 to 2003 in a series of papers by Kenneth F Nicholson.
    http://arxiv.org/abs/0806.1131v4
    
    I simply hope to raise the awareness of these shortcomings to encourage more complete evaluations of extremely complex galactic and other large scale gravitational effects in the hopes that it can be determined that neither dark matter nor modified gravitational equations are necessary, only the more correct application of established gravitational theories. Thanks.

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93. 93. stevenmcs 03:22 AM 1/9/11

    Matter interacts and gives off or absorbs light when the electrons change orbits. However, what if dark matter is made of protons with the electrons stripped off. You wouldn't be able to detect it from long distances. We always assume that protons have electons but that may be because we live in an area where electrons are abundant but the dark matter could exist in an area where electrons are scarce.

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94. 94. ktperera 06:38 PM 1/9/11

    McGaugh says, the "baryonic tail wags the dark matter dog."
    or
    There is a conspiracy between real matter and dark matter.
    Very true, because I have derived and found the connection between real matter and so called dark matter, using a concept of an additional space dimension I call the dark space. Unfortunately dark space is as difficult to prove as dark matter is. Maybe it is time to investigate on the dark space concept.
    See my article at http://cosmicdarkmatter.com/Newtonian_Dynamics.html
    

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95. 95. iward in reply to stevenmcs 11:59 AM 1/10/11

    Or some of it could be neutrons as in neutron stars.

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96. 96. bewertow in reply to jameylynne 09:46 PM 1/10/11

    I seriously doubt that you have a phD in physics, unless it was printed off the internet. Your paper seems very amateur. You say that the "idea of singularities has spread like a herpes infection." That screams idiot to me to say something like that in a scientific paper. Also, your proposed solutions are much worse than the existing theories, and rest on completely baseless assumptions.

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97. 97. bewertow in reply to jameylynne 09:48 PM 1/10/11

    Also, you clearly don't understand how supernovas occur, and the fact that you did not even take the time to research this shows that your degree is just as fictional as the ideas in your paper.

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98. 98. poeteye 11:31 PM 1/11/11

    DARK MATTER
    -- James Ph. Kotsybar
    
    The universe is mostly abnormal,
    if we accept that physicists aren’t wrong
    and Newton’s gravity’s uniformal,
    otherwise galaxies couldn’t last long.
    
    They’d spin themselves apart, unless, unseen,
    missing mass resolves the disparity.
    Dark Matter is needed to intervene.
    Though not found, it can’t be a rarity.
    
    “Shining stars are like icebergs,” they patter,
    “if the mathematics are to be served.
    There’s as much as five times normal matter
    needed to resolve dynamics observed.”
    
    Though they’ll say science is observation,
    that can tweak, if it fits the equation.
    

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99. 99. Anton 05:39 PM 1/12/11

    The Unified Vorticii Theory (UVT) provides a valid and potential explanation of both what, and how, Dark Matter and all the other forces in the Universe work together, in one encompassing and complete Theory of Everything. I don't believe there needs to be any doubt about Dark Matters' existence just yet.

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100. 100. MBCilek 04:27 PM 1/15/11

     hi folks,
     it seems that both Newton and Einstein was correct..
     there is no need for modification of any laws nor the invention of any exotic particles as Dark Matter..we must all be very sorry that Dark Matter has occupied so many decades of scientific history..it is the biggest blunder of all and the efforts to verify it are futile..straightforward math, simple physics and everything will be revealed soon, on Feb 14..
     cheers...

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101. 101. jtdwyer in reply to MBCilek 11:19 PM 1/15/11

     I agree with your basic premise, but I suggest you keep your announcement upbeat. You have to be extremely careful not to offend all of those who have spent their careers working on more complex interpretations, lest they spend their and their students' remaining careers dedicated to discrediting your solution. Good luck with the math.

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102. 102. MBCilek in reply to jtdwyer 04:26 AM 1/16/11

     I fully agree with you and that is why I said "we must all be sorry...", not "they..".
     normally I am not that arrogant and I do this just to attract some attention..I am neither a cosmologist nor a phyisicist (but a perfectionist electrical engineer) and somebody should take it seriously when I announce the hypothesis..I also need your suggestions on how to announce the article without being stolen, which is very concise, maximum 2 pages long..
     On the math side there is nothing complex (freshmen level at most), and you would believe me if you could have seen it..nothing new, no novel ideas or models, no weird conceptualizations, everything is based upon what we already know..you will probably have a big-wide smile now but "cosmology will never be the same again" :)
     I intend to put here a short summary when the time comes with the hope that you all will help me to publicize it..
     my sincere thanks for your interest and support.
     
     strawberry-at-ttmail-com

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103. 103. MBCilek in reply to jtdwyer 10:42 AM 1/16/11

     JT,
     by the way I just had a quick look at your thesis on the earlier pages of this blog..If I had understood well, u are basically saying that since galaxies are vast structures, farther orbiting material is more subject to local gravity effects (or anomalies shall we say) rather than the central one..that should be true, but..
     local anomalies (like in different parts of the density waves of spiral arms) will tend to cancel each other yielding a zero sum (when integrated) over a given orbit..that is, a higher velocity will be countered with a lower one somewhere near or far..the result of this will be more scattering of the data points on your graph (more noise we can say) but the location of the fitted curve will still be the same, which should converge to the inverse sqrt of radius..
     and it is not..oops, Houston we got a problem here..
     let us then manufacture something to correct this, hmmm... shall we call it Dark Matter then ??
     
     

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104. 104. jtdwyer 06:07 PM 1/16/11

     I strongly recommend that you make your announcement by entering an annual essay contest held by the Gravitational Research Foundation, before April 1, 2011. Please see:
     http://www.gravityresearchfoundation.org/competition.html
     
     I think the only way to protect your work would be to copyright it, but I'm no expert there. As you can see, I'm freely offering my ideas to the general public, since I'm not capable of producing a complete, publishable work, and don't have the energy if I could.
     
     Thanks very much for your comments.
     
     While I realize that mathematical cancellation occurs in vector summation, I think there is a disconnect with physical effects: I don't believe that a person situated precisely between two identical black holes in a binary pair would 'feel' no gravitational effect, even though their 'attraction' vectors would mathematically cancel.
     
     While I understand that that modelers like to represent the discs of spiral galaxies as a simple fluid masses, in which spiral arms are merely density waves flowing through the fluid 'particle' mass, the rotational velocity evidence strongly suggests that inner disc centripetal forces are applied to the spiral arms as a loosely bound structure.
     
     I wrote an essay last year (not entered in any contest) you might like to review - please feel free to contact me directly: "Mass Distribution Characteristics Invalidate the Galaxy Rotation Problem";
     http://sciencewithoutfiction.com/uploads/Mass_Distribution-_Galaxy_Rotation_Problem.pdf
     
     A retired aeronautical engineer, Kenneth F. Nicholson, produced a series of papers around 2000 describing a method of analytically producing the observed galactic rotational characteristics. They are all referenced in a paper by a professional physicist, Dilip G. Banhatti, whom I have corresponded with. Please see "Newtonian mechanics & gravity fully model disk galaxy rotation curves without dark matter";
     http://arxiv.org/abs/0806.1131
     
     Please feel free to use any of my ideas that might in any way be useful - I'm simply motivated to resolve this issue.
     
     I'll post a current summary of my thoughts below. Thanks!

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105. 105. jtdwyer 06:08 PM 1/16/11

     The laws of Planetary Motion empirically derived by Kepler and refined by Newton correctly apply only to massive objects that are, in effect, independently orbiting a dominating central mass. The Sun, for example, is estimated to contain 98.8% of total Solar system mass.
     
     Stars within the discs of spiral galaxies, mostly located in their spiral arms along with massive gaseous clouds, do not independently orbit any centralized object of mass, or even a centralized aggregation of massive objects: their primary gravitational influences are relatively nearby, neighboring objects of mass.
     
     That the spiral structures exist is more likely direct evidence that their masses are held together at least in part by local gravitational effects. That spiral arms originate within the galactic bulge and windingly radiate to the periphery of the disc indicates that at least some of the centripetal force applied to the inner disc can be structurally transmitted to stars at the periphery of the disc, counteracting centrifugal forces produced by peripheral rotational velocities.
     
     Even in a conveniently simple disperse fluid representation of galactic discs attempted by some modelers, two discrete spiral waves somehow winding their way throughout the disc, some local cohesive force must bind the fluid ‘particles’ together, allowing energy waves to pass through them as a structural unit.
     
     The laws of Planetary Motion do not correctly apply to spiral galaxies because they do not represent a sparse distribution of independent planets independently orbiting a single dominating massive object.
     
     That stars within the discs of spiral galaxies did not produce the expected diminishment of rotational velocities with increasing distances did conflict with the laws of gravitation, only their interpretation as they apply to planetary systems. The Galaxy Rotation Problem was a misperception that did not require compensatory additional mass or any altered gravitational effects to explain their specific rotational characteristics. Galaxies only require that their particularly vast distributions of localized masses, and therefore their specific distribution of gravitational effects, be fully considered in their evaluation.

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106. 106. even2 11:18 PM 1/23/11

     Regarding Dark Matter
     I was surprised that know one has considered magnet fields as a contender for dark matter. These two fields one shaped like a giant dinner plate reaching from the galaxy ecliptic centre to beyond the galaxy perimeter and the second magnetic field lines intersecting at each spiral arm attached to a star in each cluster. These would hold the galaxy together without the need of dark matter.

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107. 107. jtdwyer in reply to even2 08:12 AM 1/24/11

     I know of no indication that the observed gravitational effects of planets with magnetic fields is categorically distinguished from those without gravitational fields. It would seem that following your suggestion, magnetic fields should also contribute to the gravitational forces effecting planets.

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108. 108. jtdwyer 08:32 AM 1/24/11

     Regarding the source of the perceived requirement for dark matter, several papers authored by F. I. Cooperstock and collaborators also assert that inadequacies in the methods used to evaluate galactic gravitational effects were responsible for producing the perception that additional undetected mass must be present. Those papers include "General Relativity Resolves Galactic Rotation Without Exotic Dark Matter", 2005;
     http://arxiv.org/abs/astro-ph/0507619
     and "General relativistic dynamics applied to the rotation curves of galaxies", 2010;
     http://arxiv.org/abs/1101.3224
     
     Both papers specifically present gravitational evaluation methods for properly representing the disperse masses of galaxies based on the gravitational equations of general relativity, citing the limitations of Newtonian equations.
     
     In the recent paper, the researchers point out the mass distribution distinctions between planetary systems and galaxies that produce the differences in gravitational evaluation results. As have I, these researchers assert that no enormous amounts of additional mass, purportedly provided by dark matter, is necessary. Fortunately, they are able to do so in the context of established physics theories.

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109. 109. Hooshang 03:39 AM 1/26/11

     Part III
     Alternatively, matter-energy IS the universe. Both are true. This duality is not a contradiction. They are just two different representations of the same universe; either geometry or matter-energy. In short, but hard, we need to look for: Either, F (x1, x2, x3, x4)=0; or, independently, Y (p1, p2, p3, p4)=0; distributions of mass-energy vs. energy-momentum components. Finally, we may need to establish the “orientation” of the fields with respect to geodesics. Einstein equations may serve as this final step. As an everyday example, we need a road map, independent of which, we need cars, which ARE on the roads. We choose to analyze either the properties of the roads, or the behavior of the cars, both equally informative, and finally we may establish the relationship of the cars to the roads. Cars dictate the road map, and follow it. The bold statement: Cars “are” the roads.

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110. 110. Hooshang 03:46 AM 1/26/11

     
     Bruce please comment
     Part(I)
     On Einstein Equations
     In general theory of relativity, we have metrics, gμν, which are the properties of space-time. The properties that we assign to these metrics, say, through Einstein Tensor, explain the universe. We need to find a way to find out about these properties, for example, by some formulation involving ONLY metrics.
     Alternatively, we can start with Tμν, energy-momentum tensor; find a way to describe its properties, through a formulation involving only T.
     We are not allowed to mix these two alternatives. For example, if g satisfies, an equation like, Rμν(g)= k g, then solution to this equation, explains the universe.
     

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111. 111. Hooshang 03:49 AM 1/26/11

     Part(II)
     Alternatively, we could explain the same universe by solving equations, say, Tμνα=K δμνα, where, these equations have nothing to do with the metrics. We are not allowed to mix these two equations forming two different representations of the same universe, as is done the Einstein equation. This mixing is the main reason behind the problem of starting with a vacuum and end up with dark energy! To me, geometry of space-time IS the universe. Alternatively, matter-energy IS the universe. Both are true. This duality is not a contradiction. They are just two different representations of the same universe; either geometry or matter-energy. In short, but hard, we need to look for: Either, F (x1, x2, x3, x4)=0; or, independently, Y (p1, p2, p3, p4)=0; distributions of mass-energy vs. energy-momentum components. Finally, we may need to establish the “orientation” of the fields with respect to geodesics. Einstein equations may serve as this final step. As an everyday example, we need a road map, independent of which, we need cars, which ARE on the roads. We choose to analyze either the properties of the roads, or the behavior of the cars, both equally informative, and finally we may establish the relationship of the cars to the roads. Cars dictate the road map, and follow it. The bold statement: Cars “are” the roads. Therefore, Tμν=0 is the vacuum with NO energy. But Gμν=0, DOES NOT, necessarily, represent the vacuum. It represents the dark energy, say.

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112. 112. Hooshang 03:52 AM 1/26/11

     part(III)
     We were not supposed to mix, as in, Gμν∝Tμν. The same criticism applies to the Maxwell’s equations, and wherever we have the problem of vacuum singularities. The Dirac Equation is supposed to describe electron and NOT the electron plus infinite sea. Again, mass is mixed with space-time. The space-time geometry IS the mass. There is no energy in the VACUUM, by definition. Therefore, there are no vacuum fluctuations (a contradictory concept). To avoid singularities in physics, we need a new approach, or even a new mathematics. The time, physicists have spent to deal with singularities, could be used to invent a new theory. Logic Considerations Let’s use logic to analyze the problem. Scenario (1): “Matter Is Energy”. In this expression, Matter is “Name” or “Object”. “Is” is a (justified) Belief, or Knowledge. “Energy” is a first order concept. Quantify this expression as: E (electron)= 9.10938188×10-31Kg, say. Here, electron is the “name” or “object” or “matter”; E is the concept of energy; “=” is the “justified belief”, or “knowledge”. The number is a “value” of “The Truth” values, namely, “The True” and “The False” values. More generally, we have energy-momentum, P=(P1, P2, P3, E), as the first order concepts. Before we analyze above statement, we need to establish that: “Matter Does Exist”. The “Existence” is a second order concept, under which, the above first order concepts, P, fall. Again “Matter” is the “Name”; “Does” is the “belief”; “ Exist” is the second order concept; in other words, ∃ Matter for which, Mass=value, say Quantify the second order concept generally as energy- momentum stress tensor, Tμν(P), under which the first order concepts, P, fall. In this scenario there is no mention of space-time concepts.

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113. 113. Hooshang 03:54 AM 1/26/11

     Partr(IV)
     Scenario (2): “Space-Time Is Curved”; first order concept. “Space-Time Do Exist”; second order concept. Quantify through Einstein tensor, Gμν(X), or Rμν(X); X=(x, y, z, t). So, we have two different second order concepts; (1) Tμν(P) (2) Gμν(X) With two different first order concepts, respectively, P, which fall under T, X, which fall under G The very important question is: ARE WE ALLOWED TO EQUATE G AND T? Are they identical concepts? Do they map to the same “The Truth” values? Einstein thought so, namely, in geometrical units, he wrote: (1) Gμν(X) =8πTμν(P)? It appears that the left hand side is in “ space-time representation”, while the right hand side is in “energy-momentum representation”, especially in the light of the Heisenberg uncertainty principle: ΔXαΔPα∼hα; (no sum over α); hα=Plank’s constant. Using the Fourier transform on the left hand side only, we have in energy-momentum representation,
     (2) (1/2π)-2∫∫∫∫ Gμν(X) exp (i Pβ X β) d4 X=8πTμν(P)
     Where, X=(x, y, z, t), and P=(P1, P2, P3, E).
     

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114. 114. even2 11:57 PM 1/26/11

     reply to jtdwyer regarding magnetic fields
     I am confident that as observation techniques improve all planets will be shown to have magnetic fields.Our moon that was thought to be dead contains magnetic fields.
     As for gravitational fields before Einstein it was widely believed that gravity was part of the electromagnetic force. So far the graviton has not been seen or captured. I am confident that eventually gravity will be shown to be part of the electromagnetic force.

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115. 115. verdai 06:32 PM 1/28/11

     Thank you Very much for saying "space time DO exist".

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116. 116. dr777who 02:39 PM 2/12/11

     if we had a parallel universe
     would it also have energy and gravity
     
     is your dark matter and dark energy from a parallel universe?
     
     or do strings have energy and gravity
     and since strings are everywhere
     how about strings as dark?
     

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117. 117. dr777who in reply to carpefishus 02:51 PM 2/12/11

     what is the difference between Ether
     and strings?
     
     they look the same to me!

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118. 118. doc120 01:26 PM 3/25/11

     Could dark matter be the stuff of a parallel universe?

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119. 119. jack.123 06:46 PM 5/7/11

     I must have been educated wrong.I was educated that redshift was the drag of a photon against space-time,the longer a photon traveled the more red shifted it became.The analogy of the Doppler effect fits in here somewhere,and I am sure someone can explain why space-time is not itself Dark-mass-energy.

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120. 120. jtdwyer in reply to jack.123 11:40 AM 3/17/12

     I've never been educated, but I think that's not even wrong. If you consider the Doppler shift of sound waves in air, sound frequency changes only if the distance between the emitter and receiver changes. If there's not change in distance there no change in wavelength even though in the explanation you were taught any drag would still exist.
     
     The same goes for light waves in space. If the relative distance between emitter and receiver does not change (this occurs for relatively proximal emitters that do not exhibit any 'peculiar' motion relative to the receiver). That the wavelength of all light from distant (extragalactic) objects is redshifted infers that the distance between the emitter and receiver has increased since the light was emitted (due to spacetime expansion).
     
     There is no physical entity defined in general relativity that corresponds to the abstract dimensional coordinates of spacetime used to describe the effects of gravitation - there is no known material medium of spacetime that could, through physical interaction, induce 'drag' on photons.

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121. 121. efolger 09:42 PM 1/13/13

     Dark matter ... ether ... pholgisten?
     

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