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Space Science

Dark Matter Discovered 386

sebFlyte writes "Wired is reporting that scientists have come up to a solution as to where all the matter in the universe actually is. Experiments being done with Chandra, NASA's X-ray telescope have shown up a likely candidate for the solution of the dark matter problem. There are massive quantities of Baryons in a super-heated gas cloud several hundred million light years away."
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Dark Matter Discovered

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  • Wrong Name (Score:4, Insightful)

    by unclem0nkey ( 741514 ) on Thursday February 03, 2005 @08:10PM (#11568101)
    In physics we don't call it dark matter. We call it "make the theory fit the data" matter.
  • by FalconZero ( 607567 ) * <FalconZero@Gm[ ].com ['ail' in gap]> on Thursday February 03, 2005 @08:12PM (#11568126)
    This should be "Missing Matter Discovered" not "Dark Matter Discovered"
    They HAVE NOT found dark matter, they've found the 'missing matter' as the article says. They have found a clue as to the dark matter, as a result of the discovery.
    Although discovering the dark matter would be much cooler, (yeah I was excited when I read the title).

    [rant] Why is it the only 3 times I've 'emailed the on duty editor' before publishing, I've been ignored and the mistakes gone through?? [/rant]
  • by ejamie ( 765128 ) on Thursday February 03, 2005 @08:20PM (#11568177) Journal

    Is how do these extremely difficult scientific questions get answered so quickly lately.

    It was just a couple days ago that slashdot reported that dark matter was being postulated as the reason for the extra mass of galaxies:

    Simulating the Universe with a zBox [slashdot.org].

    Now, in less than a week, we have proof for the existence of dark matter? Amazing!

    How can scientists go from hypothesis to proof in such a short time? Are we really progressing by such leaps and bounds? Or, is this an example of media jumping to conclusions about initial research.

  • Re:Ummm (Score:4, Insightful)

    by Tlosk ( 761023 ) on Thursday February 03, 2005 @08:20PM (#11568179)
    You seem to be under the impression that we know what dark matter is and isn't. Dark matter is postulated given gravitational effects that would arise from mass that we cannot detect, hence dark.

    If it turns out that it is normal matter after all, and we just had trouble seeing it, we have still "discovered dark matter."

    Another way of putting it would be, who killed the prime minister of Georgia? If it turns out later that it was an accident from a faulty space heater, did we find out who killed him? Just becuase we were expecting a who and got a what doesn't mean the question wasn't answered.
  • by turnstyle ( 588788 ) on Thursday February 03, 2005 @08:26PM (#11568228) Homepage
    It seems to me this story isn't actually about "dark matter" -- it's about locating some missing baryonic matter (ie, regular stuff).

    In other words, if regular stuff is about 5% of the energy density of the universe, with dark matter at about 20%, and dark energy at about 75% -- the stuff in this story comes into that 5%, ie, regular stuff and not dark matter.

  • Re:Baryons (Score:2, Insightful)

    by Anonymous Coward on Thursday February 03, 2005 @08:30PM (#11568267)
    Just a wonderful definition. So now in order to understand what a baryon is, I must understand:

    1) Particle physics
    2) Nucleons, Hyperons, Fermions
    3) The strong nuclear force
    4) Fermi-Dirac Statistics
    5) The Pauli Exclusion Principle
    6) Hadrons, Quarks, and Pions
  • by temojen ( 678985 ) on Thursday February 03, 2005 @08:52PM (#11568417) Journal
    Through the power of jumping to conclusions... on the part of the person who submitted this to slashdot. It wasn't dark matter that was found; it was missing normal matter.
  • by davie ( 191 ) on Thursday February 03, 2005 @08:55PM (#11568450) Journal
    There are massive quantities of Baryons in a super-heated gas gloud several hundred million light years away.

    At least there were, several hundred million years ago.

  • by Jaborandy ( 96182 ) on Thursday February 03, 2005 @08:56PM (#11568451)
    There is a problem of assumptions here. The reason all these simulations say that there is missing matter is that they share one faulty assumption -- the Big Bang. If you stop to consider for a second that maybe the Big Bang theory is just a theory, those simulations don't say anything except what MIGHT happen if the Big Bang theory were true. Since they show that lots of additional matter must exist, then either the theory is flawed or there must be more matter somewhere.

    As more experiments and opbservations come in, we consistently see that any additional matter we find is not nearly enough to satisfy the simulations of the Big Bang. They've been trying to find this missing matter to "save the theory" for a long time now, and this is another pebble, but they haven't found it yet. I personally am convinced that the Big Bang is a defunct theory. You don't have to be convinced yet, but I am.

    If you want something to chew on, read "The Big Bang Never Happened" by Eric J. Lerner. It has details and citations aplenty.

    To those of you for whom this idea is new, remember this post. In ten years when everyone "knows" that the Big Bang is a dead theory, you can say that you knew that way back in 2005.

    --Sandy
  • Re:Ummm (Score:2, Insightful)

    by IWannaBeAnAC ( 653701 ) on Thursday February 03, 2005 @09:17PM (#11568603)
    No, the ratio of baryon matter to total matter has been established independently. Baryons are not a 'dark matter' candidate and have not been for a long time now.
  • Re:Baryons (Score:3, Insightful)

    by dspeyer ( 531333 ) <dspeyer&wam,umd,edu> on Thursday February 03, 2005 @09:37PM (#11568717) Homepage Journal
    Yes, that was a particularly embarrising bit of technobabble they misused. The most common baryons are protons and neutrons. Therefore, Baryons make up roughly 99.99% of normal matter. If they swept out the baryons, there'd be nothing left.
  • by mbrother ( 739193 ) <mbrother.uwyo@edu> on Thursday February 03, 2005 @10:44PM (#11569090) Homepage
    First, this result only applies to BARYONIC dark matter, which is only a fraction of all the dark matter out there. Second, we already knew that a lot of it at the epochs in question was in the form of hot intercluster gas.

    The current work is an improvement over previous studies, and is good work. But the headline rather sucks. I thought we'd detected axions or something, even though I'd already read about this result.

    I teach techniques to estimate cluster masses based on X-ray emission, and have used the Chandra X-ray Observatory myself. A headline about such work shouldn't trick me.
  • by mbrother ( 739193 ) <mbrother.uwyo@edu> on Thursday February 03, 2005 @10:48PM (#11569112) Homepage
    If you just think astrophysics is math, you'd flunk the heck out of my astronomy exams no matter your mathematical sophistication. Probably every level of astronomy, from non-major to graduate level. At least the way I teach it.

    Math is a very useful tool in astrophysics, but there's a reason that math is a separate department from any physical science.
  • Re:In case.... (Score:2, Insightful)

    by Anonymous Coward on Friday February 04, 2005 @02:59AM (#11570044)
    I think you just don't get it. Moderating that post informative made it twice as funny.
  • by Anonymous Coward on Friday February 04, 2005 @07:08AM (#11570700)
    Excuse my cynicism, but I find it hard to believe that you don't know as much physics as a masters student (and no good schools accept masters students), but you know a LOT about gravity. Gravity is one of the most difficult fundamental subjects in physics. Most physicists never learn GR.

    And btw we don't observe the Hubble constant within our own solar system as well. There are many things that we do not and cannot observe in our backyard.
  • Re:Bullshit! (Score:2, Insightful)

    by Dunbal ( 464142 ) on Friday February 04, 2005 @08:07AM (#11570868)
    Most of science is speculation, and therefore, shouldn't be taken seriously.

    You're obviously not a scientist then.

    "Speculation" is what drives science (ie. I observe something then I speculate as to what a possible explanation could be). But it doesn't stop there. That's where experimentation comes in, to throw out my hypothesis, or not. Science is actually the whole process, not just the initial attempt at explaining an observation.

    Speculation would be "Diet Coke is fattening, because most fat people drink diet coke".

    This is not science. You have to PROVE your statment. And not only that, but you have to publish HOW you derived the proof, so that everyone can see it and has a chance to spot errors in your technique. AND everyone has to be able to obtain the same results as you got. Then it becomes science. That's about as far away from speculation as you can possibly get.

    Now if you want to know about doppler shift and how interstellar/intergalactic distances are measured and all the "theory" and "speculation" behind it, you can pick up any physics textbook.

    If you flip a light switch and the light fails to come on there are only two possibilities: There is an interruption in the circuit (ie the lightbulb burned out, most commonly) or there is no power to the circuit. There is no speculation as to the results (ie maybe I was bad and God didn't want the light to come on as punishment).

Scientists will study your brain to learn more about your distant cousin, Man.

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