Follow Slashdot blog updates by subscribing to our blog RSS feed

 



Forgot your password?
typodupeerror
Get HideMyAss! VPN, PC Mag's Top 10 VPNs of 2016 for 55% off for a Limited Time ×
Space Science

New Hubble Release Puts Another Nail In the Coffin of Dark Matter's Competitors (spacetelescope.org) 274

StartsWithABang writes: When it comes to the structure of the Universe — forming the galaxies, clusters, and Universe as we see it — the normal matter we know of simply isn't enough. Given our best-understood laws of physics, including Einstein's general relativity, what we see of galaxies and the Universe in general simply doesn't match up to our predictions. The simplest solution, arguably, is to just add a new ingredient: a new form of matter, a dark matter if you will. But a counterargument is that we've got the laws of gravity wrong, and that no new matter is necessary. There's only one way to settle an argument like this: with data, evidence and the full suite of observations at our disposal. The newest Hubble release, along with four other independent lines of evidence, rule out modifications of gravity and leave dark matter as the only option standing.
This discussion has been archived. No new comments can be posted.

New Hubble Release Puts Another Nail In the Coffin of Dark Matter's Competitors

Comments Filter:
  • Handwavium (Score:5, Insightful)

    by Anonymous Coward on Friday October 23, 2015 @05:26AM (#50786123)

    Dark matter is still handwavium. The best proof we have for it so far is that if it isn't there the model we use doesn't work.

    • I am sure the possibility must have been explored that "dark matter" and "dark energy" originate in other dimensions. Is there clear evidence to discount this?

      • by nightcats ( 1114677 ) <nightmeow.gmail@com> on Friday October 23, 2015 @06:48AM (#50786251) Homepage Journal
        That actually makes some intuitive sense. My only problem with "dark matter" is the term itself: I saw recently in Nature (the science mag) that one astronomer had proposed the term "transparent matter," which I like a lot better.
      • That's my favorite explanation.

        Note that unlike Ockham, I think we should go with the most fun of the hypotheses that haven't been ruled out, rather than the simplest.

    • Re: (Score:2, Insightful)

      by delt0r ( 999393 )
      Oh god. Not this again. There really is no better explanation. It may feel handwavium to you, but that is because you are willfully ignorant of the data and the theory. There is more data backing up darkmatter than global warming. Also we go through the same ignorant replies below for this topic.

      /. Home of people that think they are smart because they can configure a router, but really its a bunch of illiterate idiots.
    • But that's true of everything. The only reason we know the sun exists is that if it isn't there our model for predicting what we should see
      when we look up doesn't work.

    • Re:Handwavium (Score:5, Insightful)

      by wonkey_monkey ( 2592601 ) on Friday October 23, 2015 @07:40AM (#50786371) Homepage

      The best proof we have for it so far is that if it isn't there the model [which we have created based on our observations of the universe] we use doesn't work.

      So... that'd be like... science, then?

      • by MTEK ( 2826397 ) on Friday October 23, 2015 @09:41AM (#50787031)

        I'm not saying it's science... but it's science.

      • Re:Handwavium (Score:5, Informative)

        by AthanasiusKircher ( 1333179 ) on Friday October 23, 2015 @10:10AM (#50787207)

        The best proof we have for it so far is that if it isn't there the model [which we have created based on our observations of the universe] we use doesn't work.

        So... that'd be like... science, then?

        THIS.

        Not only that, but the entire concept of modern science is predicated on mathematical models of phenomena that can't be observed directly or explained in detail (at least at first).

        Our classic history story of the Scientific Revolution often misses this point. We have this vision of people like Copernicus and Kepler and Galileo standing up against ignorant buffoons who refuse to recognize empiricism. But that wasn't it. Scientists had been doing empirical observation for thousands of years. Scientists after Copernicus rapidly (late 1500s) started looking for evidence of the earth's motion -- like stellar parallax and coriolis "forces." They couldn't measure any, and they ultimately weren't measured until the 1800s. That was a major impediment to the heliocentric theory.

        But another one was Aristotle's theory of physics, which was wrapped up in detailed explanations of "causes" for everything. And everything in the universe had its "natural place" -- terrestrial matter was assumed to always come to rest, because that's what empirical observation shows us.

        If the earth was in some sort of perpetual motion, what caused it? What maintained it? Why didn't the earth fly out of its orbit? Why couldn't we seem to measure it?

        The first three questions were answered when Newton's theory of universal gravitation came along. There was this magical unseen force called "gravity," which kept the universe in order.

        Many scientists, who believed solidly in empiricism, were highly skeptical of Newton's "occult" forces. (The word "occult" comes from the Latin meaning "hidden" or "unseen," and "occult" phenomena such as unseen forces like magnetism and gravity were associated with "magic" in the 1600s -- not "science" as we understand it.)

        Newton responded to his critics by publishing an addendum to later editions of his Principia (usually known as the "General Scholium") which basically said, "Yeah -- those weird invisible 'forces'? I admit they might not be real. But the point is that the math works out, and thus this can be a model for scholarly investigation, even if we can't observe these forces directly or attribute an Aristotelean 'cause' to them."

        THAT was really the crux of the Scientific Revolution. Many scientists came to accept Newton's theory, even before the first empirical evidence of heliocentrism (stellar aberration) was measured in the mid-1700s. The math worked, and thus the "model" worked. Even if we couldn't explain all the details, that was now "science."

        The history of science after Newton is filled with stories of theories about stuff we couldn't observe directly (electrical charges, atom models, etc.), but which we assumed to exist because they were consistent with the math and the empirical observation. It's also filled with apparent "failures" of invisible things like phlogiston and luminiferous ether.

        But those weren't really "failures" of science. They were theories based on rational empirical observation -- they may have lasted a little longer than they should have, but when they were first posited, they were reasonable explanations of what might be going on.

        We STILL don't have a complete explanation for how the invisible force of gravity works. But it's well-accepted part of science. Dark matter is no different. Maybe someday it will go the way of phlogiston, but right now it's one of the best explanations around. The fact that dark matter was invented to serve a place in a mathematical explanatory model is the very definition of modern science.

        • by Zalbik ( 308903 )

          Damnit, now I wish I hadn't commented and just modded your post up instead.

          This is a much better and more detailed answer than the one I attempted here [slashdot.org]

          No mod points, but here, have a doughnut:

          O

        • Yeah, I think that's pretty much what I said ;)

    • Re: (Score:3, Interesting)

      by ivano ( 584883 )
      It's only handwavy because you don't want to take the time to understand the evidence for it and against it. There is a lot of evidence for the WIMP model of dark matter, including the current data just posted and things like the Bullet Cluster.
    • The best proof we have for it so far is that if it isn't there the model we use doesn't work.

      If it is there the model works perfectly. We can see the effect it has on gravity, we just we don't know how to detect it directly.

    • Re:Handwavium (Score:5, Insightful)

      by Black Parrot ( 19622 ) on Friday October 23, 2015 @08:04AM (#50786449)

      The best proof we have for it so far is that if it isn't there the model we use doesn't work.

      That's kind of how science works: you notice an effect, assume there is a cause, generate some guesses about what that cause might be, and then start weeding them out.

    • A lot of physics is simply at the "placeholder" stage, as we know next to nothing about it - how does gravity work? How does magnetism work? We can say there are gravity waves and magnetic fields but we don't actually understand the underlying mechanisms of either, yet they form the cornerstones of a lot of our current understanding of the universe around us.

    • Re:Handwavium (Score:5, Informative)

      by Xyrus ( 755017 ) on Friday October 23, 2015 @08:26AM (#50786553) Journal

      Dark matter is still handwavium. The best proof we have for it so far is that if it isn't there the model we use doesn't work.

      No, it isn't.

      If you're hunting for a bear and you find bear tracks, bear shit, bear claw marks on trees, and everything except for directly observing the bear itself, you don't say the bear is "handwavium" and all of the evidence was really caused by a mutant chicken just because you didn't "see" the bear itself.

      Dark matter is exactly the same. We've measured. We've observed. The evidence points to some sort of weakly interacting/non-interacting form of matter. We can't "see" it, but we see the effects it has on everything else. It's the best and simplest explanation we have at the moment.

      Now you may not like it. You may think there's a better explanation. But until you put forth your theory with evidence to the contrary that not only explains the current observations but also doesn't break current physics it's simply your unsubstantiated opinion.

      • But we've never actually seen a bear, so it might as well be a mutant chicken. It's a difference between the known unknown and the unknown unknown.
        • But we've never actually seen a bear, so it might as well be a mutant chicken.

          Presumably we've never seen this "mutatnt chicken" thing either. So why don't we just call whatever we find a bear, since it will probably have the properties we're expecting (makes bear tracks, leaves bear poop);.

      • Maybe I'm nitpicking, (okay, I am) but this analogy assumes you already know what a bear is and have seen bears before, and bears are definitely known to exist. It'd be more like, you see tracks of some sort, claw marks of some sort, scat of some sort, but you don't really know what made them because you've never seen or heard of a bear before, but the evidence is also unlike any creature you've ever seen before.. which leaves room for imagination and educated guesswork.
        What if gravity just begins to beh
      • I will add that TFS is wrong and that dark matter isn't some "new form of matter." It's called dark matter for the simple reason that it doesn't emit nor reflect sufficient light for us to see. The three forms of matter we're most familiar with - solid, liquid, gas - are all dark matter in the absence of a sufficiently powerful energy source (sunlight). The answer could be as simple as the typical Oort cloud being a lot denser or extending a lot further than we theorize. And we simply can't see that mat
      • The evidence points to some sort of weakly interacting/non-interacting form of matter.

        The hypothesis of Dark Matter can not be taken seriously until there is some way to falsify it.

        But until you put forth your theory with evidence to the contrary that not only explains the current observations but also doesn't break current physics it's simply your unsubstantiated opinion.

        Dark Matter in fact DOES break current physics. There is no theory of matter that exists that can explain a mass that does not interact with anything and yet creates gravity.

        Th universe is pure energy. "Condensing" this energy creates matter, which creates space-time. I would argue that our understanding of space-time is insufficient, not that our understanding of matter is insufficient.

        Does this imply modificatio

    • by DRJlaw ( 946416 )

      Dark matter is still handwavium. The best proof we have for it so far is that if it isn't there the model we use doesn't work.

      No, the best proof that we have is gravitational lensing by dark matter halos that have become separated from their associated galaxies after merger events.

      Big 'ol concentration of mass with no visible matter = dark matter. The fact that you either weren't aware of the 'best proof' or cynically chose to omit it is irrelevant. It's still observational evidence that is not based up

    • Re:Handwavium (Score:5, Informative)

      by MozeeToby ( 1163751 ) on Friday October 23, 2015 @09:09AM (#50786797)

      What.

      No.

      We have several empirical results that point to a decoupling of the majority of the mass in a galaxy from it's light emitting matter. The bullet cluster shows us two galaxies colliding, we can see the light from both galaxies coalescing around each other. By measuring gravitational lensing, we can also see that the majority of the mass of those galaxies passing right through each other without interacting.

      We know beyond any reasonable doubt that the majority of the mass in the universe does not interact with regular matter, does not produce light, does not interact with light beyond gravitational lensing. That is literally the definition of what dark matter is. There are a handful of viable theories (probably only 2 or 3 likely ones) as to what form that matter takes, but that hardly means we don't have evidence of dark matter existing.

    • by ceoyoyo ( 59147 )

      Like Neptune!

      Actually, like all the planets. And all the stars. We've never actually weighed any of them, but we know their masses because of their gravitational interaction.

    • by Zalbik ( 308903 )

      Wrong. Dark matter is a theory proposed to explain existing observations.

      Science is not an absolute "this is how the world works". If you want absolute answers, turn to religion.

      Science is an evolving process of "this is our best explanation for how the world works". There is no "proof" in science. Science is observe, measure, theorize, confirm. If you don't like the current theory of dark matter, feel free to propose your own theory that matches existing observations.

      Calling it "handwavium" withou

    • Dark matter is still handwavium. The best proof we have for it so far is that if it isn't there the model we use doesn't work.

      Then come up with a better model that fits all of the observed data. (You'll probably win a Nobel Prize.)

      That's how science works.

  • Co-gravitation (Score:3, Interesting)

    by os2fan ( 254461 ) on Friday October 23, 2015 @06:15AM (#50786203) Homepage
    None of the references point to co-gravition, or Heaviside's force, which seems to produce much of the desired results called for. Co-gravitation just requires to rethink the nature of energy, though, since it implies that the gravitational field is a sink of energy, Flag as Inappropriate. A good deal of work has been done by the likes of O. Jeffimenko, and more recently T de Mees. Heaviside suggested the necessary forces in 1893.
    • by Xyrus ( 755017 )

      None of the references point to co-gravition, or Heaviside's force, which seems to produce much of the desired results called for.

      Yes, all those references on over unity are really convincing. Love the youtube anti-grav videos as well. I'd tell you more but the gubmit will probably be breaking down my door to steal my plans for the Death Star. :P

      Sorry, I don't believe in conspiracies or magic.

      • conspiracy
        knspirs
        noun
        a secret plan by a group to do something unlawful or harmful.
        "a conspiracy to destroy the government"
        synonyms: plot, scheme, plan, machination, ploy, trick, ruse, subterfuge; informal racket
        "a conspiracy to manipulate the results"
        the action of plotting or conspiring.
        "they were cleared of conspiracy to pervert the course of justice"
        synonyms: plotting, collusion, intrigue, connivance, machination, collaboration; treason
        "conspiracy to commit murder"

        • by HiThere ( 15173 )

          Sorry, but conspiracies are not necessarily illegal. Most aren't. Even the ones that are legal tend to be quite secretive, because the motivation for conspiracy is generally to benefit the members by use of hidden information. But not all conspiracies are even secretive, as some benefit merely be conjoined actions.

          Con-spiracy: To breathe together. As in people gathered around a table.

          • You can argue the definition if you choose, I just posted the definition off of Google.

            A conspiracy is when multiple people plot to do something. Yes, it doesn't have to be unlawful, as the definition says unlawful OR harmful, but I can't imagine a conspiracy that was legal, so I am not sure what you mean by that.

  • Why so negative? (Score:5, Insightful)

    by wonkey_monkey ( 2592601 ) on Friday October 23, 2015 @07:42AM (#50786375) Homepage

    New Hubble Release Puts Another Nail In the Coffin of Dark Matter's Competitors

    Well that's a gloomy spin on it. What about "New Hubble data advances scientific understanding of the universe. Go science!"?

    • by ceoyoyo ( 59147 )

      Because the defining characteristic of science is that you test your crazy ideas and figure out which ones might be true.

      • Because the defining characteristic of science is that you test your crazy ideas and figure out which ones might be true.

        By rejecting the ones that can't be true.

        And that's exactly what's happened. One of dark matter's competitors has been tested and is now in the "can't be true" box.

  • What about if spacetime itself has some properies? Eg. tension? At relatively short distances the curvature of spacetime diminishes with r^2. However, as we go further and further from the center of the curvature, spacetime reaches flatness slower and slower. This can explain the galaxy rotation problem and other phenomena which requires dark matter.

    This is similar to what MOND tries to achive, but unfotunately MOND does not say anything about spacetime.

    • by ceoyoyo ( 59147 )

      Read the article. They tested a relativistic version of MOND that DOES say things about spacetime. It failed. Modifications of gravity also fail to explain things like the bullet cluster.

  • I've seen some speculation that dark matter could be a previously unseen heavy neutrino. I also understand based on current theories there should be a lot more anti-matter than is seen now in the universe. So my armchair physics idea is there was some reaction as part of the matter/anti-matter annihilation in the early universe that converted a lot of the anti-matter into the dark matter forms of heavy neutrinos. Has this idea been pretty much ruled out already?

  • Can anyone post on the current understanding of electrical forces on galactic scales?

    A while back I read a bunch of papers on preprint archives suggesting that the effects that we see as dark matter could be caused by the electric force. I don't have my bookmarks handy, but I recall some credentialed and not-obviously-crazy physicists saying that the idea had enough merit to warrant investigation.

    Has that gone anywhere?

interlard - vt., to intersperse; diversify -- Webster's New World Dictionary Of The American Language

Working...