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Space Science

Mysterious Dark Matter Blob Confounds Experts 151

Posted by Soulskill
from the dark-matter-needs-vacations-too dept.
mayberry42 writes "Astronomers using the Hubble Space Telescope are mystified by a merging galaxy cluster known as Abell 520 in which concentrations of visible matter and dark matter have apparently come unglued. A report on the Hubble observations, published in the Astrophysical Journal, raises more questions than answers about a cosmic pile-up that's occurring 2.4 billion light-years away. 'According to our current theory,' says Arif Babul, the study team's senior theorist, 'galaxies and dark matter are expected to stay together, even through a collision. But that's not what's happening in Abell 520. Here, the dark matter appears to have pooled to form the dark core, but most of the associated galaxies seem to have moved on.'"
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Mysterious Dark Matter Blob Confounds Experts

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  • by busyqth (2566075) on Saturday March 03, 2012 @07:06PM (#39234555)
    I'm pretty sure this headline is about my recent visit from the plumber.
  • Move on (Score:5, Funny)

    by oldhack (1037484) on Saturday March 03, 2012 @07:10PM (#39234575)

    The galaxies are gone. Horse has already left the barn. Spilled milk. Water under the bridge.

    Dark matter needs to buck up, get it together, and move on, get on with the life. There is a whole universe out there.

    • Dark matter needs to buck up, get it together, and move on, get on with the life.

      Maybe it's some kind of Dark Matter "Occupy Galaxy", or something . . . ?

    • by snowgirl (978879)

      The galaxies are gone. Horse has already left the barn. Spilled milk. Water under the bridge.

      No shit... best estimates are that this happened 2.4 billion years ago, so... yeah, grow up dark matter...

      • by Vaphell (1489021)

        imo you can't really say 2.4 billion years ago. That would make sense only if there was one universal time scale with the necessary requirement of information being broadcasted instantaneously. Considering that it's not possible (hard cap of c), every point has its own time and events happen when information about them, spreading at the speed of light reaches said point. For us on Earth that dark matter stuff is happening right now.

        • by snowgirl (978879)

          imo you can't really say 2.4 billion years ago. That would make sense only if there was one universal time scale with the necessary requirement of information being broadcasted instantaneously. Considering that it's not possible (hard cap of c), every point has its own time and events happen when information about them, spreading at the speed of light reaches said point. For us on Earth that dark matter stuff is happening right now.

          Yeah, well, you're just speaking within your reference frame. In my reference frame, I'm located at a point equidistant in space and time from both this event, and you, and I see you responding to this event 2.4 billion years late...

          Of course I won't actually see the light from you responding to this post until at the earliest 1.2 billion years from now... but since I can violate causality with my tachyon emissions, I've already witnessed your observation, and response, and responded myself....

          All that asid

    • The asgard chuckle....

  • by Zakabog (603757) <john.jmaug@com> on Saturday March 03, 2012 @07:19PM (#39234635)

    From my understanding of dark matter, isn't it likely yhat they're looking at two entirely different types of matter? I thought dark matter was just matter that we can't "see" but can detect due to it's gravitational effect on visible light. So why would it be so far fetched to think there's more than one type of matter in the universe that we can't currently directly observe?

    • Re: (Score:3, Funny)

      by Dunbal (464142) *

      isn't it likely yhat they're looking at two entirely different types of matter?

      Yup, typical response from physicists for oh I dunno almost the past 100 years. Can't explain something? Must be a new particle...

      • by Anonymous Coward

        You say that like it's a bad thing. Or a wrong thing. There's a lot of people who seem to think that Science is something for settling very large issues, so that when it is wrong, it is very very wrong: believing that red things are actually green, or something like that. This is almost never the case: Science is the search for the least wrong understanding of the universe, and for the most part we understand the universe well. In this case, the alternative theories suck. In particle physics, we have scient

      • by Livius (318358)

        No, you're thinking of the scriptwriters of Star Trek Voyager.

      • by osu-neko (2604)

        Yup, typical response from physicists for oh I dunno almost the past 100 years. Can't explain something? Must be a new particle...

        Yup. Can't explain something, but it would be explained if a certain particle with such and such properties exist, let's go look for it... and lo, there it is! It's amazing what you can discover if you're willing do more than just throw up your hands and say, "hmm, can't explain that."

        • by drinkypoo (153816)

          Has anyone seen an anti-photon yet?

          • Photons are their own anti-particles.

            • by drinkypoo (153816)

              Nobody has even seen the first photon, we only can measure its intersection with something. Pretty sure nobody has seen the antiphoton that mediates the exchange of energy, either, but maybe you've got some magical specs from the back of a comic book that let you do that.

              Since we still don't know what photons actually do in between the time they're emitted and the time we can observe them, we've just got a working model that lets us predict where the photon will be, then really it could all be working very

          • by Fastolfe (1470)

            Yes, it's called a "photon".

    • by Baloroth (2370816)
      No, that isn't far fetched at all, and it is entirely possible (maybe even likely). However, the philosophical principles that guide science dictate that we should reduce effects to the fewest possible number of causes. If two causes suffice to explain the phenomenon, one should not introduce a third. You can introduce new principles/causes/etc ad infinitum, but unless they are required to explain the observations, they are more or less worthless. In other words, one should postulate only as many kinds of m
    • by Rich0 (548339) on Saturday March 03, 2012 @10:52PM (#39235675) Homepage

      There are other possible ways that the same phenomena could lead to different outcomes. How about this one - galaxies/clusters are composed of stars and hot gas, and that's it - there is no dark matter. However, we exist in a multiverse with many parallel universes overlaying ours but interacting only through gravity. Since matter in different universes attracts each other, galaxies in one universe tend to be piled on top of galaxies in other universes. Much of the mass of any cluster/galaxy is in the hot gas.

      Now, let's take the bullet cluster. Let's explain that by the collision of 4 clusters in three universes. Universe A is ours, and B and C are others that are close by and interact gravitationally. Two of the clusters are in A (call them 1 and 2), one is in B (call it 3), and one is in C (call it 4). 1 and 3 overlap, and 2 and 4 overlap. When they cross paths, the hot gas in 1 and 2 interact via electromagnetism, and the hot gas in 3 and 4 only interact gravitationally and aren't slowed down as much. In the end the gas in our universe in clusters 1 and 2 ends up in the middle, and the gas in 3 and 4 are visible as dark matter on the outside.

      As the second example let's consider this collision. Let's explain that using 4 clusters in two universes, again with A being ours and B being another one. Clusters 1 and 2 are in ours, and 3 and 4 are in B. 1 and 3 overlap, as do 2 and 4. In this scenario the hot gasses in 1 and 2 interact, and so do the hot gases in 3 and 4. That means that the hot gases all end up in the middle in all 4, and the stars all fly past each other and end up on the outside. So, this time we see hot gas in the middle, plus a lot of dark matter, which is all the hot gas in 3 and 4.

      So, we can have "dark matter" behaving in two different ways, not because of any difference in the matter itself, but rather a difference in the space in which it exists.

      No doubt somebody much smarter than me has thought up something like this already, and perhaps shot it full of holes as well.

      • Interesting theory and similar to things I've wondered about too. It might one of those theories that's very difficult to prove either way.

      • What you're talking about is very similar to the effects of braneworld theories, where our universe is living on a 3D brane to which we're confined. There are, of course, other branes hanging around in the wonderful 11D multiverse. In M theory, gravitons are closed strings and can float freely between the branes, while photons (and, indeed, the rest of the standard model particles) are open strings whose ends are confined to a brane. (Note that saying "In M theory" is itself a bit dubious since M theory doe

      • by mbone (558574)

        The way I prefer to state this is that "Dark Matter" is a sign that there is something we don't know about the physics of large scale matter. We know that there is missing physics, but we don't know where it is. If it is in some new "Cold Dark Matter," (or CDM) the missing physics is in quantum field theory. If, as in Milgrom's MOND [wikipedia.org] hypothesis, the problem is with gravity on large scales or weak accelerations, the missing physics is in gravitation. Your idea would put the missing physics in extra-dimension

      • by lewiscr (3314)

        The Galactic Rotational Velocity [wikipedia.org] implies that dark matter is something different than standard matter, not just invisible matter. I'm broadly covering all forms of invisible matter here, cold-dark matter, non-baryonic matter, matter in other branes, etc.

        Using your idea with the galactic rotational curve, the thought exercise would not yield the required mass distribution to explain the rotational curve.

        Now, if we posit that nearby branes don't necessarily have the exact same physical constants, that could

        • by Rich0 (548339)

          Good point - just dumping a second galaxy on top of our own in some other universe would put too much mass in the center. Maybe as you suggest if constants were different it would be more sparse and we'd have more mass outside.

          If you allow for a much larger number of nearby branes then maybe gas that is gravitationally coupled to the galaxy might work. Gas might fall from voids and tend to orbit a galaxy in our universe, but since it doesn't interact non-gravitationally it wouldn't clump as much near the

          • by lewiscr (3314)

            Sorry for the fast thinking here. I'd written a much longer post, but /. ate it when I tried to login.

            What is the psuedo-distance between branes?

            We know that gravity's effects drop of as distance^2. Working under the theory that gravity propigates at the speed of light, we can measure brane distance in light seconds. If branes are only a light-second away, there's too much mass. Too many branes too close together would turn everything into a black hole.

            If we assume some non-trivial distance between bran

    • Nothing likely wrong about positing multiple types of dark matter...

      But what I think is really bothering folk about the supposed contradiction here is why would one galaxy or galaxy cluster have one type and another galaxy or galaxy cluster have another? This in and of itself would seem to be a rather flagrant violation of the Mediocrity Principle.

      It would seem more likely that both galaxies would have a blend, if you will.

      Is there a time component here? Would dark matter be different in one epoch vs. ano

      • by Raenex (947668)

        But what I think is really bothering folk about the supposed contradiction here is why would one galaxy or galaxy cluster have one type and another galaxy or galaxy cluster have another? This in and of itself would seem to be a rather flagrant violation of the Mediocrity Principle.

        Not necessarily. Galaxies come in many different types:

        http://en.wikipedia.org/wiki/Galaxy#Types_and_morphology [wikipedia.org]

    • by Raenex (947668)

      From my understanding of dark matter, isn't it likely yhat they're looking at two entirely different types of matter?

      This was one of the possibilities (the third one below) raised in the article:

      "Jee, Babul and their colleagues propose several possible explanations for the discrepancy. One explanation might be that the dynamics of the Abell 520 collision are more complex than the Bullet Cluster's crash. Maybe multiple collisions, involving three or four galaxy clusters, have led to the dark matter pile-up.

      Another possibility is that there's actually lots of ordinary galactic material in the core, but it's just too dim to

  • I've seen this before [imdb.com].

    We are all DOOMED!

  • tribbles! (Score:2, Funny)

    by Anonymous Coward

    Must be a cosmic pile-up of tribbles.

  • Awoken (Score:4, Funny)

    by roman_mir (125474) on Saturday March 03, 2012 @07:38PM (#39234749) Homepage Journal

    Awoken the Grue has been.

  • by GodfatherofSoul (174979) on Saturday March 03, 2012 @07:40PM (#39234755)

    Make sure to call me if that blob starts moving towards earth!

  • by RichyRoo (2553726) on Saturday March 03, 2012 @08:15PM (#39234903)
    If Abell 520 has had the DM 'stripped from its galaxies' (from the link) and since DM was originally postulated to explain the difference between theoretical and observed rotation rates of the core and periphery of galaxies... shouldnt the galaxies of Abell 520, stipped of their DM, now be rotating in accordance with the original theory? That is to say, if gravitational theory predicts that, sans DM, the cores of galaxies will rotate more quicky than the periphery, and these galaxies are now 'sans DM', wouldnt that open the opportunity to provide falsification or support to the DM hypothesis by checking if the galaxies of Abell 520 are indeed rotating differently now that the DM has been removed?
    • by l0ungeb0y (442022)

      Care to tell us how they were rotating previously?

      • by RichyRoo (2553726) on Saturday March 03, 2012 @09:30PM (#39235289)
        In theory the cores of galaxies should be rotating faster than the periphery, however observation contradicts this. So the hypothesis was postulated that there was additional 'dark' matter surrounding galaxies which could cause the periphery to rotate faster. If Abell 520 has had its dark matter removed, its periphery should be rotating in accordance with standard gravitational theory, rather than as effected by invisible dark matter. Its pretty simple really.
        • by osu-neko (2604)
          Yes... and in a few million years, we can compare it to the images we took today and see if that's the case...
        • by mbone (558574) on Saturday March 03, 2012 @11:56PM (#39235891)

          In theory the cores of galaxies should be rotating faster than the periphery, however observation contradicts this. So the hypothesis was postulated that there was additional 'dark' matter surrounding galaxies which could cause the periphery to rotate faster.
          If Abell 520 has had its dark matter removed, its periphery should be rotating in accordance with standard gravitational theory, rather than as effected by invisible dark matter. Its pretty simple really.

          Falsifiable ? Yes, but probably not this way. First off, A520 is a cluster of galaxies, not a single one. The dark matter orbiting the galaxy core is going to be tightly bound to that galaxy, and won't be stripped by a cluster collision. And (see my post below), anyway it's not the stars, but the gas that gets separated from the dark matter.

        • I don't understand why stars should rotate as planets do. In our system there are 8 small (relative to the sun) planets scattered across several billion miles. In a galaxy there are 100 billion stars rotating -- so wouldn't the gravitational effect of one star on the next be substantial? In the extreme density case of a rotating solid object, all parts of the object rotate at the same speed. Aren't a galaxy's stars "more solid" than our solar system's planets?
  • Obviously, the Death Star detritus, along with the burntout hulks of various starships blown out of existence by Luke and Hans and that furr-faced fellow, had to congregate someplace........
  • The theories existing now are obviously wrong. Scientists, especially cosmologist these days are always puzzled, perplexed, surprised, mystified and confounded by the unexpected data that does not fit into any of their theories. There are theories that other people have come up with that don't require dark matter, dark energy, black holes and other convoluted mathematical constructs that have never been observed in real life. Maybe it is time to throw out the old theories and consider some of these theories

    • Maybe some of those alternate theories that have been labeled âoecrackpotâ need to be looked at more seriously in light of the flood of data confounding, perplexing and fooling current mainstream scientists.

      Maybe the crackpots should present some real evidence instead of acting so much like, well, crackpots. Specifically, maybe they should submit their work for publication and stop posting their "results" on web sites full of eye-bleeding color schemes, pretty Hubble pictures (which are, BTW, published by those evil "mainstream" scientists) that have nothing do to with the issues at hand, accusations of censorship and suppression by The Scientific Establishment, and "refutations" of existing theories that all

      • Many scientific theories held by the majority, sometimes for centuries, were overthrown by observant people working alone. Some of these were never vindicated by majority scientists until many years after these lonesome scientists died. There are many examples of this. I will just give one.

        For centuries it was the consensus among scientists, that the speed of light was instantaneous, that is it took no time at all to travel any distance. There were even “experiments” done with lanterns and shutt

        • Many scientific theories held by the majority, sometimes for centuries, were overthrown by observant people working alone.

          But unlike the typical crackpot, they understood the theories they overthrew. And they replaced them with better theories, not with ideas which already had been shown to be wrong long ago. And they didn't have to deny experimental results either, nor claim some conspiracy against their ideas.

        • Many scientific theories held by the majority, sometimes for centuries, were overthrown by observant people working alone.

          Alas, Bozo the Clown worked alone too.

    • by bmo (77928)

      The thing is that the people who are /always/ wrong are the ones who are cocksure, such as yourself.

      When you change the model to fit the data, we call that science.

      Everything else is snake oil, religion, and dogma.

      --
      BMO

      • When you change the model to fit the data, we call that science.

        And when you change the data to fit the model, we call that marketing.

    • by Raenex (947668)

      Scientists don't just "throw out" theories if they can be patched and no solid alternative exists. They do, however, look at plausible alternatives:

      http://en.wikipedia.org/wiki/Dark_matter#Alternative_theories [wikipedia.org]

      Dark matter is just the prevailing theory. Working scientists know that it might be wrong and the equations for gravity may have to be fixed.

    • by osu-neko (2604)

      There are theories that other people have come up with that don't require dark matter...

      These theories are even more at odds with the observed effects here than our current theories. What we're seeing in this case is dark matter behaving in an unexpected manner. A theory that posits dark matter doesn't even exist would have a much, much harder time explaining its observed behavior...

    • by osu-neko (2604)
      BTW, what you're suggesting here is the equivalent of saying, "oh look, the Earth's magnetic pole isn't moving exactly the way our theory predicts -- we should toss out this crackpot theory that the Earth is round."
  • FTS: A report...published in the Astrophysical Journal, raises more questions than answers about a cosmic pile-up that's occurring 2.4 billion light-years away.

    Should that be "occured 2.4 billion years ago"?

    • by Daniel Dvorkin (106857) on Saturday March 03, 2012 @09:59PM (#39235467) Homepage Journal

      It's pretty conventional, when discussing astronomical observations, to use the present tense for "when we see it." Since it can't possibly have any effect on us before the light from the event gets here (assuming relativity is correct, yadda yadda) this makes sense. Also, having to say "2.4 billion years ago 2.4 billion light-years away" would just get annoyingly redundant after a while.

      There's pedantry which serves the useful purpose of correcting other people's mistakes, and then there's pedantry of the "look how clever I am" variety; posts like yours, which seem to get posted to every single story on any kind of astronomical event that takes place outside the solar system, are examples of the latter.

      • by bmo (77928) on Saturday March 03, 2012 @11:01PM (#39235701)

        There's pedantry which serves the useful purpose of correcting other people's mistakes, and then there's pedantry of the "look how clever I am" variety; posts like yours, which seem to get posted to every single story on any kind of astronomical event that takes place outside the solar system, are examples of the latter.

        There is an excellent word for this and it means far more than just "pedant" and it's Finnish.

        The word is pilkunnussija, literally "comma fucker"

        The more you know.

        --
        BMO - perkele

        • Oh, that's brilliant!

        • by dwye (1127395)

          Is the Finnish pilkunnussija different from the netnews-era English-writing term grammar nazi?

          Anyway, the correct response to shotgun's original question is that the two formulations are equivalent in this case, much like the response to asking if a square shouldn't be called an equi-angle rhombus rather than a rectangle with equal length sides. If the collision had been merely inferred (like that between Thetis and the pre-moon Earth) rather than observed using light (which moves at the presumed-fixed spe

    • by osu-neko (2604)

      FTS: A report...published in the Astrophysical Journal, raises more questions than answers about a cosmic pile-up that's occurring 2.4 billion light-years away.

      Should that be "occured 2.4 billion years ago"?

      To be perfectly pedantic, it should be "that occurred 2.4 billion years away". Your "correction" is making an entirely different statement, which although true, is not what the original was saying.

  • If it gets you you'd best jump into a pressure chamber, it's you only hope.
  • by wbr1 (2538558) on Saturday March 03, 2012 @10:28PM (#39235615)

    Mysterious Dark Matter Blob Confounds Experts

    My ex-wife confounds me too.

  • I see the experts were Confounded.

    Does anybody know if they were also Baffled, or Stumped? It would also be good to know if they were also left Scratching Their Heads?

    Oh yeah, were they Dumbfounded too?

    • by bmo (77928)

      "The trouble with the world is that the stupid are cocksure and the intelligent are full of doubt." -- Bertrand Russell

      And you have proved which one you are.

      --
      BMO

  • The Default (Score:4, Insightful)

    by rust627 (1072296) on Saturday March 03, 2012 @10:53PM (#39235677)

    The default position for scientists is "I don't know"
    everything else is trying to define and explain
    this is why nothing is set as a certainty but always as a theory
    a Theory (theory of gravity, theory of climate change etc.) is usually the best most simple hypothesis that explains experimentally verifiable data.
    you can create any theory you want from the incredibly convoluted to the overly simplistic (because god made it so strikes me as an overly simplistic theorem).
    Usually the simplest (but not most simplistic) theory will be the one that gains the most credence in the scientific community.
    the KISS rule applies very much in science too.

  • It must be cold sweat left behind by two fighting galaxies.
  • by mbone (558574) on Saturday March 03, 2012 @11:43PM (#39235833)

    This should not be too confounding. Suppose you have two galaxies collide. The dark matter will sail right through the other galaxy, affected only by the overall gravity. The stars will almost never hit each other, so the vast majority of them will be affected only by the overall gravity too. The gas and dust will not - dust is subject to radiation pressure, and gas (plasma) magnetic fields. Once the gas and the dark matter become separated, there is no guarantee they will ever get back together. As the paper says :

    One of the key tools for studying merging clusters is the comparison among the distributions of the three cluster constituents: galaxies, hot plasma, and dark matter. For example, in merging clusters the intracluster medium suffers from ram pressure and lags behind galaxies and dark matter, which are believed to be effectively collisionless. The contrast between collisional and collisionless components becomes highest when we observe merging clusters at their core pass-through, when both the medium velocity and the effect of ram pressure stripping are largest.

  • >2012
    >Still using Hubble
    >Costanza_smirking.jpg

    In all seriousness, I am impressed this thing is still working. I would have thought it was retired by now. Way to go, Nasa!

    • by mbone (558574)

      It is still working because it was serviceable, and was serviced. (It is no longer scheduled to be, so it won't last too much longer.) That is a rare thing at NASA, which tends to be dominated by people who would rather spend money building things.

  • It dragged them down unnecessarily and nobody figured any way to use it for anything so they schemed a plot to leave it behind.

  • Don't know the double slit test? (Yeah right, geek) Go here : http://www.youtube.com/watch?v=DfPeprQ7oGc [youtube.com]

    In it, a photon targeting photo film through a double slit creates an interference pattern when left unobserved during the process. However, if one attempts to observe/detect the photon traveling through both slits, it only travels through one, leaving 2 standard lines. The typical take from this is that quantum uncertainty breaks down because the process was observed, forcing a choice to be made. Howe

Entropy requires no maintenance. -- Markoff Chaney

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