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Space Science

New Theory Challenges Need For Dark Matter 302

Posted by Soulskill
from the propagating-through-the-ether dept.
New submitter elsurexiste writes "An Italian Physicist came up with a strange way to explain anomalous galactic rotations without dark matter, instead relying on the gravitational effects of faraway matter. The article explains, 'Conceptually the idea makes little sense. Positioning gravitationally significant mass outside of the orbit of stars might draw them out into wider orbits, but it’s difficult to see why this would add to their orbital velocity. Drawing an object into a wider orbit should result in it taking longer to orbit the galaxy since it will have more circumference to cover. What we generally see in spiral galaxies is that the outer stars orbit the galaxy within much the same time period as more inward stars. But although the proposed mechanism seems a little implausible, what is remarkable about Carati’s claim is that the math apparently deliver galactic rotation curves that closely fit the observed values of at least four known galaxies. Indeed, the math delivers an extraordinarily close fit.' As usual, these are extraordinary claims that divert from the consensus, so keep a healthy skepticism. The paper is available at the arXiv (PDF)."
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New Theory Challenges Need For Dark Matter

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  • No (Score:5, Funny)

    by Anonymous Coward on Monday December 05, 2011 @03:54PM (#38271484)

    I'm sorry, but "gravitational effects" won't sell popsci books. For the sake of our royalties, let's stick to dark matter.

    • Re:No (Score:5, Funny)

      by vandon (233276) on Monday December 05, 2011 @03:57PM (#38271510) Homepage

      Yes, I agree. Dark gravity deniers should be kicked out of their profession. Once a consensus is reached, it is recognized as FACT!

      • Re:No (Score:4, Insightful)

        by ilguido (1704434) on Monday December 05, 2011 @05:21PM (#38272842) Homepage
        The parent post is more insightful than funny. Sadly it is more insightful than funny.
      • Re:No (Score:4, Informative)

        by SecurityTheatre (2427858) on Monday December 05, 2011 @05:48PM (#38273234)

        His model is less accurate than that which is predicted by dark matter. The fact that it does align with several known observations makes it at least worth consideration, but realistically, there are a dozen or more theories about this, most of which are a little crackpot.

        To entertain alternatives because the consensus theory is still in doubt is healthy, but the consensus still represents to most scientists, the most plausible and will continue to drive current research efforts until a new model is proven fairly conclusively, to be more accurate.

        This is how science works and it is not broken. I can clearly tell you are not a scientist and you also have issues with other science that may or may not have plausible alternative models, which may or may not match current observations and experimental results with more or less success, but which still haven't caught on because of gaps in their explanations of various observed phenomena.

        The scientific method isn't perfect, but it serves us well in general and it is worthwhile to stick with it in order to attempt to explain our surroundings. Are you implying otherwise?

        • Whoosh!
        • Re: (Score:3, Informative)

          by mc6809e (214243)

          "His model is less accurate than that which is predicted by dark matter."

          Dark matter doesn't predict anything. Dark matter is a thing hypothesized to exist that might explain our observations.

          • by jo42 (227475)

            Dark matter is a thing hypothesized to exist

            Just look between a Republican's ears to find dark matter.

        • by tenco (773732)

          The point is, they don't have to declare the existence of some new property of reality but maybe can explain it (if the physics and math hold) with existing properties. Occams razor.

      • Re:No (Score:5, Insightful)

        by DesScorp (410532) <<DesScorp> <at> <Gmail.com>> on Monday December 05, 2011 @08:01PM (#38274844) Homepage Journal

        Yes, I agree. Dark gravity deniers should be kicked out of their profession. Once a consensus is reached, it is recognized as FACT!

        Heh. A few years back I was modded into oblivion when I stated that I thought Dark Matter was utter BS, a way for some scientists to make the math work despite any real proof. I think I said something like "They can't just come out and admit 'I don't know', so they pulled this out of their ass. 'The cause? Ummm. Ummm, hey, it's.... dark matter! That's the ticket!' ".

        And that's pretty much what it is. The observable universe doesn't agree with their equations, so they made something up to make the equations work. And as someone else said, "you can't fight consensus, right?".

        • Re:No (Score:5, Insightful)

          by scotch (102596) on Monday December 05, 2011 @10:52PM (#38276114) Homepage
          Dark matter *is* the scientists saying "we don't know", actually.
        • Re:No (Score:5, Insightful)

          by drolli (522659) on Tuesday December 06, 2011 @01:56AM (#38276990) Journal

          As a physicist: You are Idiot and uneducated in the history of physics. Lets take some instances of when people invented something "to make the math work" (uhm yes, thats what physicists are trying to do in the end.....)

          a) Ether Wind. They made is up "to make the math work" as an alternative to "change the underlying euquations".... And the winner was "change the underlying equations". Without specific predictions from the Ether WInd Hyphothesis one could not have constructed the Michelson-Moreley Experiement

          b) Neutrinos. Long predicted, because some momentum was missing. At that moment the neutrino was "dark matter". As we all know, Neutrinos exist. Is everybody would have believe that Neutrinos are utter bullshit because they "just ake the math work" nobody would have developed a theory for detecting them.

        • by Raenex (947668)

          A few years back I was modded into oblivion when I stated that I thought Dark Matter was utter BS, a way for some scientists to make the math work despite any real proof.

          It's called a hypothesis, and it's one of the fundamental tools of science. They then do experiments and look for collaborating evidence to see if it's right. If you want to say dark matter is bullshit, you have to say why and argue the science. Being an armchair scientist gets you no credibility.

  • by Sebastopol (189276) on Monday December 05, 2011 @03:55PM (#38271486) Homepage

    faster than light neutrino measurements?

    revolutionary-yet-pseudo-sciency sources of energy?

    and now dark matter challenges?

    coincidence or what?

    • Also (Score:5, Funny)

      by MrEricSir (398214) on Monday December 05, 2011 @03:58PM (#38271542) Homepage

      Also there was that Galileo guy too.

      (Must be all the espresso they're always drinking.)

      • Re: (Score:2, Funny)

        by Anonymous Coward

        (Must be all the espresso they're always drinking.)

        Hmmm... your espresso theory might explain some of the software made in the Seattle area in more recent years.

    • by marcello_dl (667940) on Monday December 05, 2011 @04:07PM (#38271680) Homepage Journal

      Maybe, with chronically insufficient funding, researchers work better. It'll be known as the Paradox Berlusconii.

    • Re: (Score:2, Interesting)

      by Anonymous Coward

      faster than light neutrino measurements?

      revolutionary-yet-pseudo-sciency sources of energy?

      and now dark matter challenges?

      coincidence or what?

      They'll do anything, absolutely anything, invent any figment, totally divorce the mathematics from natural philosophy, propose strange exotic forms of matter never observed, and claim their existence is "proven" because they have a favorite explanation among multiple explanations not requiring strange exotic forms of matter. They will do all of this, and more, to avoid admitting that "million degree gas" is conductive plasma and there is electricity in space and its attractive force is linear instead of fo

      • Re: (Score:3, Funny)

        by gstrickler (920733)

        A religious rant, condemning other theories as inadequate, antiquated, and conforming to orthodoxy. On the internet too. Wow, who would have anticipated that?

        • Re: (Score:2, Interesting)

          by Anonymous Coward

          A religious rant, condemning other theories as inadequate, antiquated, and conforming to orthodoxy. On the internet too. Wow, who would have anticipated that?

          ... a rant that explains why the writer believes one theory to be better than the prevailing one by reviewing the merits of both.

          I know it's trendy to just look down your nose and condemn something without actually explaining what's wrong with it and why you disagree, and certainly it's trendy to avoid setting a better example by taking a position yourself that doesn't have the qualities you're complaining about... but don't you feel like a bitch when you do things this way? No insult intended, I mean "

          • by tragedy (27079)

            Remind me how the Electric Universe theory explains nucleosynthesis? If stars are actually just big balls of iron and nuclear fusion isn't powering them, where did the iron, and all of the other elements come from? Traditional cosmology explains it pretty well, and decades of observations of stars at all stages of development supports those explanations very well. How does the Electric Universe fit with all the existing evidence?

        • by rainmouse (1784278) on Monday December 05, 2011 @05:03PM (#38272620)

          A religious rant, condemning other theories as inadequate, antiquated, and conforming to orthodoxy. On the internet too. Wow, who would have anticipated that?

          To be fair, using mathematical models on stuff we can see and measure seems a reasonable idea as opposed to inventing an invisible, incorporeal, magical material that we have no direct evidence even exists in order to compensate for our lack of understanding in how the Universe moves.

          • You mean Mathematical models like the theory of gravity? Yup, sounds pretty reasonable.

            • You mean Mathematical models like the theory of gravity? Yup, sounds pretty reasonable.

              There are other more complicated but also more plausible and elegant solutions that exist without needing to introduce dark matter. The problem dark matter attempts to solve are curves witnessed in galaxy rotation that are inconsistent with our understanding of gravity and mass. The key hypothesis is that dark matter is a dipolar fluid composed from gravitational dipoles (in analogy with electric dipole, a gravitational dipole is defined as a system composed of two particles, one with positive and one wi

          • by Anonymous Coward on Monday December 05, 2011 @08:03PM (#38274854)

            Are you daring to question existence of phlogiston, that glorious celestial substance that suffuses the luminous aether?

            Pistols at dawn, sir.

          • Re: (Score:3, Insightful)

            by Anonymous Coward

            Gravitational lensing has been observed in a bodies of dark matter... so we can see it too.

            http://en.wikipedia.org/wiki/Dark_matter#Galaxy_clusters_and_gravitational_lensing

        • by MinistryOfTruthiness (1396923) on Monday December 05, 2011 @05:10PM (#38272694) Homepage Journal

          I take it you're a member of the *resistance*? Get it? Heh, heh... er.. never mind. I'll sit down now.

      • by bucky0 (229117) on Monday December 05, 2011 @04:37PM (#38272190)

        Conventional leap of faith: this strange unseen matter exists and interacts gravitationally but somehow isn't available on Earth, cannot be created or observed or studied in a lab,

        Unless supersymmetry is RP-conserving.

        Electrical leap of faith: electrical processes explain the lack of mass through the electric force which is many orders of magnitude stronger than gravity and is more effective at long distances and is the only logical explanation for light-years-long jets of matter (Birkeland currents), can be observed in any laboratory with modest equipment and is known to scale both up and down, and through processes not yet understood there is enough charge separation in the Universe to provide the potential difference to cause these circuits to flow.

        If you're willing to believe that far off galaxies have ridiculous amount of charge separation (something we have no theories or experimental evidence for), then believing that there are weakly interacting massive particles or other forms of dark matter can't be a stretch. Electromagnetism is strong (relatively), there would have to be something really trying to hard to convince the different charges to keep apart

        I wonder how long it will be before science is forced to throw out dark matter and embrace electrical effects. Ten years? Twenty?

        It's not a matter of time, it's a matter of evidence. If you can come up with a self-consistent theory that explains these electrical effects and have predictable effects that can be measured then you can have your moment in the sun.

        • by HiThere (15173) <`charleshixsn' `at' `earthlink.net'> on Monday December 05, 2011 @05:17PM (#38272784)

          Somehow this argument sounds like the argument for continental drift before plate tectonics.

          OTOH, I note that the another comment denies that the mathematical fit is all that good. This isn't really convincing, as I heard similar denials of continental drift before a plausible mechanism was discovered.

          Still, if that it so you can expect it to continue to be rejected in a way that seems to you unreasonable UNTIL you come up with a plausible mechanism (for charge separation?). Personally I'd look at friction of intestellar gasses around the ejection plumes from black holes. Friction is well known for causing charge separation between, e.g., fur and glass. Now you've got to come up with your analogs to fur and glass...or come up with some other mechanism. But until you provide a plausible mechanism, this theory will be rejected without reasonable examination. Expect it.

          • by cowboy76Spain (815442) on Monday December 05, 2011 @09:48PM (#38275698)

            DISCLAIMER: I am not a astrophysic, and I have the good sense to not to claim that the new theory looks like better (fits observations better) than dark matter. The scientific process will eventually sort it out (and not through an /. poll). This post is not about the theory but about the posts on it.

            When Wegener postulated its theory, even if the underlying details were not fully understood, it was a scientific one because it answered to observation (size of continents, identical fossils found at different continents, etc.).

            Fortunately, there was no internet then, because there would be a deluge of posts by uninformed people who didn't knew shit of what they were talking about, but felt that theory too "radical" and that they had to restore order (go read the GGP talking about "totally divorce the mathematics from natural philosophy").

            The most funny things about those guys is that they would look at the abstract of a full scientific study and counter it with and abstract... "similar fossils? they have been spread by African swallows. Hey, that solves it, I am so sure that I won't ever check if this can be possible."

            Nowadays, we have some amateurs who take several years of observations, heavy mathematical work and just threw out of their asses "I'd look at friction of intestellar gasses around the ejection plumes from black holes". Where is your data? Your correlation of the expected results with observations? Your predictions and/or experiments?If you have some of it, don't send it to me, publish the paper to help science, please.

            Don't get my wrong, I am not annoyed by it. It could be annoying if those people were wasting someones time for this, but no scientific is going to come to /. searching for theories, so it is mostly harmless entertainment that brings a smile to my face :-)

            The funny thing is that those nutjobs always leer in the same direction, opposing the "unnatural" posibilities. Are they afraid that the world is becoming too complicated? I feel there are too many camouflaged ludites out there.

            And, finally, my goodbye present. [xkcd.com]

      • Show us the math (Score:5, Interesting)

        by Fujisawa Sensei (207127) on Monday December 05, 2011 @04:53PM (#38272462) Journal

        Just show the math and how it correctly models modern astronomical data.

        I'll give you a hint, it doesn't even come close.

      • by tragedy (27079) on Monday December 05, 2011 @05:02PM (#38272596)

        Just in case anyone isn't aware, the parent post is a rant about the "electric universe" "theory". Basically, it's pseudoscientific quackery. Not because of scientific snobbery, or some sort of conspiracy against the theory, but because most of it is quite obviously bunk. It's basically just a form of monomania.

      • by Anonymous Coward on Monday December 05, 2011 @06:01PM (#38273442)

        They'll do anything, absolutely anything, invent any figment, totally divorce the mathematics from natural philosophy, propose strange exotic forms of matter never observed, and claim their existence is "proven" because they have a favorite explanation among multiple explanations not requiring strange exotic forms of matter.

        The mysterious "Them"! A shadowy organization, nefarious and wicked.

        They will do all of this, and more, to avoid admitting that "million degree gas" is conductive plasma and there is electricity in space and its attractive force is linear instead of following an inverse-square law, totally eliminating the need for any dark matter.

        So Coulomb's Law is completely wrong just because PLASMA and ELECTRICITY IN SPAAAAAAAAAAACE!!! ? Why does nobody ever observe a linear attractive force for electric charge in the lab, under any conditions (including evacuated chambers and plasmas)?

        And how does an incoherent shambling mess of a crackpot theory (the entire family of Electric/Plasma Universe wingnuttery) believed only by ignoramuses like yourself who don't even understand that like charges repel and opposite charges attract, a theory which has been disproven a thousand times over by real scientists doing real science, a theory which never gained any traction at all because it doesn't match how the universe observably works, solve anything at all?

        Both require some kind of leap of faith. Conventional leap of faith: this strange unseen matter exists and interacts gravitationally but somehow isn't available on Earth, cannot be created or observed or studied in a lab, and is proposed to exist merely to fix a broken theory that never predicted its existence but can't get the expected results without it (Karl Popper spins in his grave...).

        Nobody requires that you take a leap of faith and "believe" in dark matter. It's just the best explanation we've got right now, and last I checked, scientists are actively searching for both confirmation and disconfirmation of dark matter. If it were a faith industry, nobody would be doing either and that would be that.

        Electrical leap of faith: electrical processes explain the lack of mass through the electric force which is many orders of magnitude stronger than gravity and is more effective at long distances

        Trying to use the electric force to explain the observations which led to the proposal of dark matter is flatly stupid. Remember what I said just above about you not understanding that the electric force is only attractive for opposite charge? If you don't accept that, you are going against every observation of the electric force, ever. If you do accept that, then you've just disproven the electric universe theory, because the observed discrepancies from Newton's Law at cosmological scales are evidence of a consistently attractive force, like gravitation. If stars and planets and clusters and so forth were actually far enough from electrically neutral for the electric force to be a significant factor in their interactions with one another, you could never find a set of 3 objects which all attracted one another. Such objects are routinely found, therefore the electric universe theory is bunk.

        So yeah, the EU theory requires a leap of faith: the kind of leap which requires you to ignore solid evidence which absolutely disconfirms the theory.

        and is the only logical explanation for light-years-long jets of matter (Birkeland currents),

        Calling LY-long jets of matter Birkeland currents is a perfect example of how EU true believers try to claim random phenomena as their own without rigorously linking them to EU theories. Birkeland's predictions related to the aurorae on Earth, not cosmological objects.

        can be observed in any laboratory with modest equipment and is known to scale both up and down, and

      • I don't know, "conductive plasma" versus "dark matter" -- they both sound pretty cool.

        The thing is, on the one hand, you're ranting about "religions with their orthodoxies and heretics and apostates", and yet on the other, you recognize that "[b]oth require some kind of leap of faith". You advocate that science should behave in a manner distinct from religion, yet you talk about "faith". (While the phrase "leap of faith" is figurative, the faith is quite literal.) I think the onus is on the party making the

      • by Edmund Blackadder (559735) on Monday December 05, 2011 @08:17PM (#38274972)

        Electromagnetic force can be easily and cheaply measured here on earth and is thus measured all the time. I find it hard to believe that we have had the wrong formula all this time and nobody noticed. And if this is the case, and Electromagnetic force decreases linearly and not quadraticaly you should be able to provide experimental proof pretty easily.

    • Maybe it's the start of the another renaissance.

    • by omuls are tasty (1321759) on Monday December 05, 2011 @04:51PM (#38272418)
      Don't forget the most unlikely event of them all - Berlusconi's gone!
    • by Valtor (34080)

      There are no coincidences...

    • by bill_mcgonigle (4333) * on Monday December 05, 2011 @05:14PM (#38272734) Homepage Journal

      coincidence or what?

      Don't forget - they also have geologists on trial for failing to predict the earthquake a few years ago. The Universe is merely seeking equilibrium.

  • Wow. (Score:4, Funny)

    by Frosty Piss (770223) * on Monday December 05, 2011 @03:58PM (#38271540)

    I'm envious of anyone who actually understands anything the summary is talking about.

    • It's pretty much high school physics. Spin yourself on an office chair and observe what happens as you move your arms or legs closer and further away from the center of your rotation. Admittedly the summary did phrase things such that I realised better why spreading out your mass changes your rotational velocity..

    • Re:Wow. (Score:5, Interesting)

      by jd (1658) <imipak@nOSPam.yahoo.com> on Monday December 05, 2011 @07:16PM (#38274400) Homepage Journal

      Not sure about the summary, but the paper is extremely simple. I'll summarize it:

      It is commonly assumed that galaxies are evenly distributed. This would mean that if you picked any galaxy at random, you could pick other galaxies whose gravitational pull totally balanced out the effect of the first one. So, overall, no distant galaxy would ever affect anything.

      What is observed is that galaxies are NOT evenly distributed. There is, indeed, left-over gravitational pull. Provided the distribution of galaxies is self-similar (which is what they mean by "fractal", since "fractal" itself has no meaning here) AND a few other constraints are valid, THEN the left-over gravitational pull would be enough to explain the rotation of the stars and gasses within the galaxy. The author's analysis of the galaxies over a relatively nearby region of space suggests to him that the distribution is indeed self-similar.

      (Summary off, analysis on)

      Is this a new theory? As a replacement for Dark Matter, yes. In any other context, no. Shepherding moons/asteroids dominate our own solar system, creating a dynamic that would be utterly unstable without them. Shepherding galaxies and super-galaxies is a new one, but if the physics is observed in other systems then the physics must be considered sound. The only question I see here is whether the distribution of galaxies is indeed self-similar. If it isn't, the theory is wrong. If it is, then dark matter - as it is currently understood - must be wrong because you now have left-over gravity and you have to alter the dark matter theory to allow for it.

      Doesn't the dark matter theory fit things well as it is? No it doesn't. Dwarf galaxies and globular clusters exhibit NONE of the signs assumed to indicate the presence of dark matter. Some don't have high-speed rotation at all. Dark matter theory cannot explain either of these and the usual answer is to say that dark matter "isn't uniform" without ever explaining why it should be missing only with certain classes of structure and not others. It's actually much easier to say that "excess" rotational velocity is a function of residual gravity and that where you have little residual gravity you have no excess rotational velocity. It is also entirely plausible to argue that "null points" are backwaters and that this explains why you get relatively few major galaxies appearing at such points but do get minor multi-stellar structures.

  • The Bullet Cluster (Score:5, Insightful)

    by Anonymous Coward on Monday December 05, 2011 @04:01PM (#38271586)

    Does this explain the gravitational lensing in the Bullet Cluster?

    This is the kind of theory that could have be viable prior to August 2006. When the gravity isn't pointing towards the baryonic matter, we have to postulate that there's some dark matter for the gravity to point to. Or, as Sean Carroll put it [discovermagazine.com]

    We have a useful phrase to describe new fields whose energy warps spacetime: “dark matter."

    • by jpmorgan (517966) on Monday December 05, 2011 @05:37PM (#38273054) Homepage

      You have to distinguish between a theory, and a model based on a theory. "Dark matter" is a hypothesis/theory... this paper on the other hand isn't proposing anything new, it's just a different way of modelling galaxies that accounts for "far-field" interactions. The theory here is just general relativity, and the author claims that when you account for the relativistic effects of distant matter in your calculations, the unexplainable rotation curves that originally justified the hunt for 'dark matter' are now explainable.

      Now this doesn't prima facie explain things like the Bullet Cluster; you'd have to redo the bullet cluster calculations accounting for these long distance effects. And of course, if it were simply the case that 'we did the math wrong and assumed something was insignificant when it isn't,' then it would be an enormous amount of egg-on-face for a lot of physicists and research groups. But personally I find it likely that the math was wrong AND there are still-not-understood dark matter/quantum gravity effects at work.

  • Yet another MOND which doesn't explain the Bullet Cluster and gravitational lensing curves.

    • Yup. Theories trying to handwave dark matter seem to pop up about once a month these days, and each and every time they seem to be in some sort of timewarp from before recent observations.

      Come on, you lazy ass cosmologist-wannabes, read the flippin' literature before you try to declare "I've got rid of dark matter!"

      • by msauve (701917) on Monday December 05, 2011 @04:17PM (#38271850)
        "I've got rid of dark matter!"

        Yeah. That's implausible. After carving up the turkey recently, the last thing left was the dark matter. Everyone seems to like the white matter better.
      • by Spykk (823586) on Monday December 05, 2011 @05:13PM (#38272730)

        Theories trying to handwave dark matter seem to pop up about once a month these days

        Can you blame them? We found a bunch of stuff that doesn't fit our model for how the universe works so instead of invalidating our model we just assume that there is something invisible influencing our numbers. I won't pretend like I know what is really going on but blaming some undetectable third-party when your model fails feels like grasping at straws to me.

      • by jd (1658)

        Recent observations fail to observe dark matter anywhere but do detect a provable absence of it around dwarf galaxies and globular clusters. This is a major problem for dark matter and may yet prove to be fatal to the theory.

        Secondly, a theory should always be as simple as possible but no simpler (Bert Einstein) and should contain no unnecessary elements (William of Occam), which is essentially the same thing. Adding in variables is complexity and it is not merely rational but absolutely key to the entire b

  • by Max Threshold (540114) on Monday December 05, 2011 @04:07PM (#38271670)
    Isn't this basically the same effect that creates the L1 point [wikipedia.org]?
  • by thegreatemu (1457577) on Monday December 05, 2011 @04:15PM (#38271792)

    Disclaimer: I do experimental searches for dark matter for a living, so I may be biased in my judgement of these types of papers that crop up so often. There was a similar paper a few weeks ago from someone claiming that quantum vacuum polarization could account for dark matter PhysOrg link [physorg.com].

    The issue with both of these explanations, is that they only address galactic rotation curves. Those are among the first and easiest to explain indications of the need for something like dark matter, but are not the strongest by a long shot. For instance, this guy's explanation can't explain things like the famous Bullet cluster [wikipedia.org], nor can they explain the evolution of structure formation or the spectrum of fluctuations in the cosmic microwave background [nasa.gov] which, in the field, are considered much stronger constraints.

    The Cold Dark Matter (CDM) theory of cosmology fits all of the astrophysical measurements reasonably well, and has a nice tie-in to supersymmetric particle physics, which is one of the current leading theories. No one in the field will take any new theory seriously until it can reproduce ALL the phenomena at least as well as the current model (which of course is exactly how the scientific process is supposed to work!)

    • hey thanks for your contribution...seems like you know what you're talking about

      I want to respond to this:

      "this guy's explanation can't explain things like X, nor can they explain Y which, **in the field**, are considered much stronger constraints."

      I dont want to squabble about X & Y...but ask you if X & Y were re-examined in a context that was absent a need for Dark Matter of any kind, is it possible that the researchers of X & Y would find another way to explain the observations?

      Of course, yes, we could find that observations of the Bullet Cluster can fit a model sans-dark matter once we apply a comprehensive understanding of black holes...or not.

      My point is, Dark Matter is as Dark Matter does...if its not an option, those PhD dissertations on galaxy collision physics are going to get written anyhow, and whatever explanation we can find will be the best until we find something better...

      sure the CDM Theory of Cosmology fits observations...we can reverse engineer ANY result we want with the data analysis tools available...the point of my post is simply to ask, "What is more important to you, volume of published research on a topic or mathematic/scientific fitness?"

      Your answer to my question is also the answer to your own questions of the External Validity of Carati's equations.

    • by Tomato42 (2416694)
      From wikipedia Bullet cluster:

      At a statistical significance of 8, it was found that the spatial offset of the center of the total mass from the center of the baryonic mass peaks cannot be explained with an alteration of the gravitational force law.

      In other words, the theory the guy is proposing is akin to Newtonian laws when we have Special Relativity. Non story.

    • I have been (and am) quite leery of DM and I have my reasons for being leery, not the least of which is the complete lack of directly observable evidence (it's dark) just doesn't cut it, tenuous clouds of heavy molecules, blah, blah what ever. When the main reason for a theory is the (follow the leader) effect and not so much a gravetic signature of ambiguous origin, I'll call all the current theories not much more than mental-masturbation.

    • by jd (1658) <imipak@nOSPam.yahoo.com> on Monday December 05, 2011 @07:51PM (#38274760) Homepage Journal

      Supersymmetry is problematic as the simplest forms are now falsified by the LHC. You have to assume a more complex form - which is valid, but I have seen no evidence that the CDM theory has been re-examined to see what the impact of the LHC observations is.

      The Bullet cluster obviously needs explaining, but I saw nothing on the Wikipedia page that indicated why Dark Matter was needed as a part of that explanation. There is clearly a drag effect of some sort, but there are plenty of potential causes of drag. Which ones are viable depend on the precise angle of each galaxy at the time of collision and the probability based on known classes of stellar object of various types of high-pressure event occurring. I would imagine that such work has been done but Wikipedia showed none that I could see.

      CMB is a problem because certain fluctuations could potentially be the result of specific multiverse theories being correct. Due to the lack of ability to see multiverses, CMB alone is not a valuable indicator because you cannot test the different hypotheses. There's no means of distinguishing a valid model from an invalid one. I am not saying CMB isn't a demonstration of dark matter, merely that it is only suggestive of being a demonstration of dark matter. Until such time that enough observations have dark matter as the only common suggested solution to all of them, the best you can say is that CMB allows for the possibility of dark matter.

  • by quax (19371) on Monday December 05, 2011 @04:18PM (#38271868)

    This is based on Einstein's field equation using perturbation theory to construct a solution for the examined case.

    My bet is on general relativity once again delivering the goods. Quite a strike against the case for dark matter.

  • by Oswald McWeany (2428506) on Monday December 05, 2011 @04:46PM (#38272338)

    Granted, I don't know anything about physics so my comment is probably unwanted and useless; however.

    I just want to say- what little I do know, I've always disliked dark-matter. It always seemed to be a case of "we can't explain 'x' - so let's claim there is dark-matter and that will make our hypothesis match what we observe."

    OK, it's more than just that- and from people way more knowledgable than me; however, I've always wondered if it was just a stop-gap explanation that would one day be disproven. (which it hasn't been yet).

    I'm grabbing my pop-corn, turning on physics Pay Per View and cheering on the anti-dark matter brigade in this fight. I'm hoping dark-matter turns out to be false. Not that I'm matterracist.

    • by Layth (1090489)

      I am in the same boat as you.

      Dark matter always sounded too far fetched for me.
      The same is true for superstring theory.. it's not something I can get behind.

      Maybe I have just contemplated the presence of a void for too long.

    • by cje (33931) on Monday December 05, 2011 @05:15PM (#38272752) Homepage

      I just want to say- what little I do know, I've always disliked dark-matter. It always seemed to be a case of "we can't explain 'x' - so let's claim there is dark-matter and that will make our hypothesis match what we observe."

      But you should realize that this technique has been used throughout the entire history of modern science, and its track record is actually quite good.

      Back in the late 1700s, after the discovery of the planet Uranus, astronomers made careful calculations of its orbital elements and published a table the position of the planet in the sky over the years (and decades). As the years (and decades) wore on, they discovered a curious thing: the actual position of the planet was beginning to diverge from what had been predicted.

      At this point, there were a few different explanations:

      1) Perhaps the initial orbital elements were incorrect.
      2) Perhaps our fundamental laws of gravity and motion were incorrect.
      3) Perhaps there was a massive, as-yet-undetected eighth planet whose gravity was influencing the orbit of Uranus.

      Most astronomers fell into the third camp; after all, the observations of Uranus's orbit had been made with considerable precision (for the time) and there was little reason to believe that the fundamental laws of physics would start to break down as you move further away from the sun. And so they made their calculations and narrowed down the location of this hypothetical planet to a fairly small window in the sky. After that, it was just a matter of pointing a telescope there and looking.

      This is the story of the discovery of the planet Neptune.

      Astronomers did not find this planet by accident. It was not discovered by a kid in the backyard with a streak of cosmic good luck. (In fact, many observers from antiquity had seen it, but had not realized what they were looking at.) They found it because they knew it had to be there.

      Now, you might think that this comparison is a bit of a stretch. But it's just one example; there are countless more. Back in 1930, Wolfgang Pauli was studying beta decay in atomic nuclei. He realized that the process, as he was seeing it, could not possibly be happening unless there were (again, hypothetical) particles being emitted as a consequence. If there were not, then all sorts of fundamental principles of physics were being violated (e.g., conservation of matter / angular momentum / etc.)

      This particle, eventually named the "neutrino", remained hypothetical and undetected for more than a quarter of a century until it was finally detected -- in 1956.

      I could go on, but the point is that postulating the existence of something hypothetical in order to explain deviations between theory and observed results is part of the best traditions of natural science. It's not hand-waving or charlatanism. And it works more often than most people might think.

      • by bjorniac (836863)

        To be fair, the flip side to the Neptune story is that of the perihelion advance of Mercury, which until the GR calculations came along, was thought to be the influence of another planet, closer to the sun. Geekgasm trivia: Due to the temperature that the planet would have to endure at such proximity it was named "Vulcan".

        Wikipedia actually does a pretty good job of telling the story: http://en.wikipedia.org/wiki/Vulcan_(hypothetical_planet) [wikipedia.org]

        Of course, no planet was found, and modifying the theory of gravity

    • by Carnildo (712617)

      I just want to say- what little I do know, I've always disliked dark-matter. It always seemed to be a case of "we can't explain 'x' - so let's claim there is dark-matter and that will make our hypothesis match what we observe."

      It was discovered in 1933 that if we add up the mass of all the stars in a galaxy and run it through either Einsteinian or Newtonian gravity, there isn't enough of it to explain the paths of those stars. "Dark matter" simply means any form of matter that doesn't emit light (the Earth

  • by Guppy (12314) on Monday December 05, 2011 @05:19PM (#38272814)

    Remember this story on Slashdot from 2005?
    http://science.slashdot.org/story/05/10/10/1052224/good-bye-dark-matter-hello-general-relativity [slashdot.org]

    "The CERN newsletter reports that a new paper by scientists at the University of Victoria has demonstrated that one of the prime observational justifications for the existence of dark matter can be explained without any dark matter at all, by a proper use of general relativity! What does this imply for cosmology and particle physics, both of which have been worrying about other aspects of dark matter?"

    Impressive sounding claims that raised a big hoo-ha on Slashdot (and are echoed in similar replies to this story), until it was pointed out that the equations contained a mistake, such that the galaxy they modeled behaved as if it had a disk-shaped singularity embedded in it. A mistake that accounted for the observed effects in the model.

    This sort of physics paper is exactly the type of preliminary result that needs to be mulled over before it front-page attention. It's pretty close to being flame-bait (and thus just ends up making everyone look stupid, except for the handful of physics experts who knew what they were talking about).

"Why can't we ever attempt to solve a problem in this country without having a 'War' on it?" -- Rich Thomson, talk.politics.misc

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