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Space Science

Hubble Survey Finds Half of the Missing Matter 189

Posted by kdawson
from the hiding-in-plain-sight dept.
esocid sends along the news that scientists believe they have found about half the missing matter in the universe. The matter we can see is only about 1/8 of the total baryonic matter believed to exist (and only 1/200 the mass-energy of the visible universe). This missing matter is not to be confused with "dark matter," which is thought to be non-baryonic. The missing stuff has been found in the intergalactic medium that extends essentially throughout all of space, from just outside our galaxy to the most distant regions of space. "'We think we are seeing the strands of a web-like structure that forms the backbone of the universe,' Mike Shull of the University of Colorado explained. 'What we are confirming in detail is that intergalactic space, which intuitively might seem to be empty, is in fact the reservoir for most of the normal, baryonic matter in the universe.'"
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Hubble Survey Finds Half of the Missing Matter

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  • Ether (Score:4, Insightful)

    by teknopurge (199509) on Tuesday May 20, 2008 @05:35PM (#23482946) Homepage
    Haven't we known this for some time?
    • Re:Ether (Score:5, Informative)

      by Anonymous Coward on Tuesday May 20, 2008 @05:39PM (#23483028)
      I knew someone was going to make an ether comment. The luminiferous ether was the hypothecial medium that electromagnetic waves (including light) traveled through. It was hypothesized because, at the time, there were no known waves that traveled without a medium. However, the ether was disproven, and it was shown that EM waves travel without a medium. What's mentioned in the article is not ether.
      • Re: (Score:2, Interesting)

        by Anonymous Coward
        Yup, Disproven.

        Because Einstein got everything perfect (cosmological constant)
        And light (which may or may not have mass) is bent by gravity (bending space time)

        Wouldn't it make more sense to go with an aether theory?

        You say light travels at the same speed regardless of direction or relative motion? I say bunk requiring some very sophisticated manipulations of time and space (Lorentz contractions) What's wrong with the 'entrained aether' theory? What, you never heard of frame-dragging?

        Gravitational lensing
        • Re:Ether (Score:5, Insightful)

          by Uncle Focker (1277658) on Tuesday May 20, 2008 @07:09PM (#23484396)

          Because Einstein got everything perfect (cosmological constant) And light (which may or may not have mass) is bent by gravity (bending space time) Wouldn't it make more sense to go with an aether theory?
          Not when it's wrong. I'm sorry if reality is too complicated for you, but that's your problem not ours.

          You say light travels at the same speed regardless of direction or relative motion? I say bunk requiring some very sophisticated manipulations of time and space (Lorentz contractions) What's wrong with the 'entrained aether' theory? What, you never heard of frame-dragging?
          No, light travels at a constant speed in a vacuum. It's speed can be different based on a whole variety of factors.

          Gravitational lensing? How about gravity increasing the optical density of the aether?
          Have any evidence to back this up?
          • Re: (Score:2, Interesting)

            by sir fer (1232128)
            disclaimer: I am a physics graduate. EM waves consist of an oscillating electric field (along with its magnetic counterpart)...what was that electric field doing before it started oscillating? It was probably a static field. Think about this, if I have a magnet and I wiggle it around, the disturbance in the field of the magnet travels outward from the source at the speed of light, but the field was there but merely static initially. Same deal with gravity waves. So whether the local field is static or osci
            • Re: (Score:3, Interesting)

              by TropicalCoder (898500)

              I've got a question for a physics graduate or anybody who can answer it. After reading for the thousandth time about all the ionized gasses in space, I suddenly began to wonder how many electrons were created in the Big Bang? Like - are there enough electrons for every atomic nucleus to fill it's shells - if they weren't ionized? Now, that seems improbable, because an enormous amount of matter was created after the Big Bang - created in stars and super novae. Then this matter that was created - were electro

              • Re:Ether (Score:4, Informative)

                by hardburn (141468) <hardburn&wumpus-cave,net> on Tuesday May 20, 2008 @09:59PM (#23486452)

                The universe likely has neutral charge [ucolick.org]. Also see a more detailed discussion [physicsforums.com] on the subject.

                • Re:Ether (Score:5, Informative)

                  by TropicalCoder (898500) on Tuesday May 20, 2008 @10:30PM (#23486776) Homepage Journal

                  Thanks! I found the answer, and read some very interesting discussion in the links you provided. Interesting that though I have been reading about physics and astronomy for many years, I have never run into this kind of discussion before...

                  "The electromagnetic force is so strong that if the universe had even a slight net charge, electric and magnetic fields should dominate the structure of our universe. But it doesn't -- gravity does. And gravity, believe it or not, is a very weak force. There are other effects that electric and magnetic fields would have on light, and we simply do not see these effects."

                  "If a gas in ionized it simply means that some electrons have separated from the constituent atoms (or molecules) that make up the gas leaving positively charged atoms/molecules and negatively charged electron. However they are still mixed together in the same gas, the 'separation' that you assume does not exist. The positive and negative charges still mingle in the same space. Even if you took a very small volume (the size of a grain of sand) of an ionized gas the overall charge is still neutral."

            • by tyrione (134248)

              disclaimer: I am a physics graduate. EM waves consist of an oscillating electric field (along with its magnetic counterpart)...what was that electric field doing before it started oscillating? It was probably a static field. Think about this, if I have a magnet and I wiggle it around, the disturbance in the field of the magnet travels outward from the source at the speed of light, but the field was there but merely static initially. Same deal with gravity waves. So whether the local field is static or oscillating, it was always previously existent regardless of its state. While I don't believe in the luminiferous aether either I also don't see how a field disturbance (electric, magnetic or gravitational) can travel through something that isn't there. I hope people can see what I'm talking about because while relativity and the aether don't make sense on their own, there are aspects of both theories that accurately describe reality and as is often the case in modeling reality it is not often a case of either / or, eg wave-particle duality in describing the sub-atomic world.

              That wave is not static, it's vibrational displacement is assumed inert/static because we have no way of approximating such a minute difference in change, for now.

            • by frieko (855745)
              IANAPG it was my understanding that a static field consists of virtual photons in much the same way that a moving field consists of 'regular' photons.

              I realize I'm saying that photons are made of EM fields which are made of photons, but well, they sorta are.
          • Evidence... (Score:2, Insightful)

            by msauve (701917)
            he has exactly as much evidence as there is for the existance of gravitons or Higgs bosons or exotic dark matter.
        • Re:Ether (Score:5, Informative)

          by naasking (94116) <naasking&gmail,com> on Tuesday May 20, 2008 @07:16PM (#23484500) Homepage
          Wouldn't it make more sense to go with an aether theory? [...] How about gravity increasing the optical density of the aether?

          The problem with ether theories is mainly the Michelson-Morley experiment. Are there ether theories which avoid the MM pitfall? Sort of. The Polarizable Vacuum [wikipedia.org] (PV) is a very interesting theory along the lines of what the the above poster suggested. Instead of matter bending some mysterious "ether", as in ether theories, or bending space-time, as in relativity, matter instead affects the electric and magnetic permeability of space, which causes light to behave as if it were passing through a medium with a higher dialectric constant. From that simple assumption, we can almost rederive full general relativity (GR) wherein electromagnetic equations produce gravitational effects. Gravity is electromagnetism! PV has since been disproven, but it's still a stunningly simple way to think about gravitation in terms of electromagnetism.
          • by neomunk (913773)
            I think the Michelson-Morley experiment fails due to it's assumption that the observation device isn't at the center of the universe. The way I look at it, the point of observation (measurement) very well COULD be considered the center of the universe. Pardon my non-university foolishness, but don't waveforms collapse outward from the point of measurement?

            Not that I'm an outspoken advocate of aether theory or anything, I've just been bugged by that little thought since high school, and this seemed like a
            • Re: Ether (Score:4, Informative)

              by EPAstor (933084) on Tuesday May 20, 2008 @10:36PM (#23486834)

              It's not quite like that... Quantum states' collapse is barely real in the sense that we know it. In particular, it doesn't carry information - so the experiments we already have, which indicate that what we call collapse is a non-local phenomenon (carries faster than the speed of light, possibly instantly), don't contradict special relativity.

              Yes, you read correctly - to all our best measurements, collapse appears instantaneous, not like a propagating change in a wave.

            • Re: (Score:3, Informative)

              by BZ (40346)
              Wave function collapse is a much more controversial thing than the existence or non-existence of the ether. Basically, it's the only non-unitary, non-differentiable, discontinuous part of quantum mechanics. Oh, and it violates special relativity, though that might count for less given the topic of discussion here. There are various suggestions (such as many-worlds theories) that might avoid the need for this artificial wavefunction collapse altogether.

              Back to the topic at hand, the interesting thing with
              • Re:Ether (Score:5, Interesting)

                by locofungus (179280) on Wednesday May 21, 2008 @03:53AM (#23489314)
                Why does wavefunction collapse violate SR? SR prohibits information traveling faster than light. The no-communication theorem http://en.wikipedia.org/wiki/No-communication_theorem [wikipedia.org] (I'd always called this the no-signaling theorem) leads to the no-cloning theorem http://en.wikipedia.org/wiki/No_cloning_theorem [wikipedia.org] so if you like, SR "explains" the no-cloning theorem. (The no-cloning theorem still allows a cloning fidelity of 5/6. Last I saw, fidelities of 0.81 had been achieved)

                Back to the topic at hand, the interesting thing with special relativity is that while it was created based on the results of the Michelson-Morley experiment, it doesn't actually "explain" that experiment.

                Maxwell's equations (see sig) predict that light will propagate with a speed c independent of frame. Einstein had a choice, Newton was wrong or Maxwell was wrong. A non-null result from the MM experiment would invalidate Maxwell's equations.

                So, if you like, Maxwell's equations "explain" the null MM result.

                Tim.
        • by treeves (963993)
          What's Einstein got to do with it? The ether theory was disproven by the Michelson-Morley experiment. Einstein was 8 years old at that time - still doing poorly in grade school.
          • Re: (Score:2, Informative)

            by hardburn (141468)

            Michelson-Morley was an important part of it, but it was Einstein that finally killed it off by proving that waves and particles aren't as seperate as they appear to be, and thus ether is unnecessary. A few stodgy professors hung on for a while, but they eventually retired/died off without convincing very many of their students.

      • Re: (Score:3, Insightful)

        by hardburn (141468)

        Not disproven, really, but fell away due to Occam's Razor. The difference between ether and this "web-like structure" is that ether was never directly observed.

        • by lgw (121541)
          I've been amuzed for years that the actual experimental equipment being built to detect gravity waves is basically the same (though far more precise) as in the Michelson-Morley experiment, but we expect to see the opposite result. In other words, the result we're looking for would have looked a whole lot like ether if found 100 years ago.
          • Re:Ether (Score:4, Informative)

            by khayman80 (824400) on Wednesday May 21, 2008 @12:21AM (#23487736) Homepage Journal
            Not exactly... The MM experiment predicted a phase shift when the optics table was rotated. It wasn't time-dependent. The phase shifts expected by LIGO/LISA are sporadic events that should only be sensitive to huge events such as black hole creation or neutron star mergers. They won't vary with the orientation of the plane of the interferometer, and they won't be constant in time either.
      • by scorp1us (235526)
        How can you disprove EM travels without a medium, if our world is made of matter in that medium? You can of course remove the matter (create a vacuum), but that doesn't remove the medium.

        I'm not trying to be antagonistic. I'm legitimately curious.
        • Re: (Score:3, Informative)

          by lgw (121541)
          Well, if you assume that the Earth moves through such a medium as it orbits the Sun, you can look for that, as you can tell there's a medium when you move relative to it - which was the Michelson-Morley experiment [virginia.edu].
      • It was hypothesized because, at the time, there were no known waves that traveled without a medium.

        Except the one for which they were trying to find a medium. :-)

    • Re: (Score:2, Funny)

      by nomorecwrd (1193329)
      Off course!

      Isn't this the matter that strikes the shields at Warp speeds?
  • Ok, fess up (Score:5, Funny)

    by pauljuno (998497) on Tuesday May 20, 2008 @05:36PM (#23482966)
    Come on, which one of you took it?
  • Dark Matter??? (Score:3, Insightful)

    by omnichad (1198475) on Tuesday May 20, 2008 @05:40PM (#23483040) Homepage
    Always wondered why a simple explanation like dust never took hold, and everyone started talking about invisible matter to explain what should be there.
    • Re:Dark Matter??? (Score:5, Informative)

      by CheshireCatCO (185193) on Tuesday May 20, 2008 @05:43PM (#23483072) Homepage
      This isn't dark matter. Dark matter shows evidence (based on its measured distribution) which is not consistent with ordinary baryonic matter.
    • Re:Dark Matter??? (Score:5, Informative)

      by Btarlinian (922732) <tarlinian@NOspaM.gmail.com> on Tuesday May 20, 2008 @05:45PM (#23483114)

      Always wondered why a simple explanation like dust never took hold, and everyone started talking about invisible matter to explain what should be there.

      We know that there is some sort of matter missing due to weird graviational interactions. We also know that according our measurements of the cosmic microwave background, this matter doesn't exist, i.e., this matter doesn't interact with electromagnetic fields. That's why it's not normal baryonic matter.

      Therefore, we say that there must be dark matter. Plain old dust would have showed up in our readings of the CMB.

    • This has zero to do with dark (non-baryonic) matter. They just accounted for half of the missing 'normal' (baryonic) matter that was thought to exist. It's still a small fraction of the total mass-energy sum of the Universe at large.
  • by Anonymous Coward on Tuesday May 20, 2008 @05:41PM (#23483052)

    We think we are seeing the strands of a web-like structure that forms the backbone of the universe

    It is a noodle like structure. FSM 1 ID 0
    • It's actually a series of tubes.
    • We think we are seeing the strands of a web-like structure that forms the backbone of the universe

      It is a noodle like structure. FSM 1 ID 0
      Of course! When touched by His Noodly Appendage, a chunk of dark matter becomes a new galaxy.
    • by rrohbeck (944847)
      But how do they handle TCP on the Intergalactic Web?
      Do the noodles transmit data FTL? Maybe they're tachyon fibers.
    • by Plutonite (999141)
      What was it like, father - what was it like to see the signs, the noodles in the sky... did He.. did He SMILE upon you? Did the Holy Sauce pore through the cockpit insulation as we heard the laymen say?

      [all around the room, anxious faces lean forward in gleeful awe to hear the blessed man speak]
  • Wow (Score:5, Insightful)

    by digitrev (989335) <digitrev@hotmail.com> on Tuesday May 20, 2008 @05:44PM (#23483096) Homepage
    That's actually pretty cool. I mean, the fact that matter was missing was a bit of a problem. The fact that it's in between galaxies even explains why it was missing. When it's that spread out, it's damn near impossible to see the gravitational effects of it.
    • Re: (Score:3, Insightful)

      Great, except the problem is that we're trying to figure out what we can measure by its gravitational effects but doesn't interact in any other way with normal matter. This is the solution to a different problem.
    • Re: (Score:3, Informative)

      by ChrisA90278 (905188)
      What was found here was missing __baryonic matter__ the bigger question is still unanswered. Bryonic matter is the normal stuff we are made of but most of the "stuff" in the universe is non-baryonic and still "missing".
    • Re: (Score:2, Informative)

      by GanjaManja (946130)
      (actually, they mention that regular matter is not detected via gravitational effects, they simply observed the absorption spectrum. However, when the gasses are highgly ionized, there are no electrons spinning around waiting to absorb the light, and thus the ionized Hydrogen does not yield an easily detectable absorption. (see 2nd article) "dark matter", non-regular matter, is detected via the gravitational lensing effects. )
  • by RealErmine (621439) <commerce&wordhole,net> on Tuesday May 20, 2008 @05:45PM (#23483110)

    "Oh, there it is."

    I'm still waiting for them to find all the missing socks.

  • by davidwr (791652) on Tuesday May 20, 2008 @05:53PM (#23483230) Homepage Journal
    Damn and all this time I thought it was an invertebrate.
  • If there is ionised oxygen and hydrogen in this space, could these combine to form water?
    • by xaxa (988988)
      Presumably, but it's probably not hot enough.

      If you put them together in a balloon nothing happens until you put a match to it, and it's probably a lot colder out in this part of space than my school's science lab was.
    • Yes. All of the water on the planet formed in deep space. Neat, huh?
      • Let me correct that. Water *can* form in very low temperatures but I read that most of it comes from supernovae.
  • by speculatrix (678524) on Tuesday May 20, 2008 @06:17PM (#23483586)
    Douglas Adams had a theory about missing matter...

    For a long period of time there was much speculation and controversy about where the so-called "missing matter" of the Universe had got to. All over the Galaxy the science departments of all the major universities were acquiring more and more elaborate equipment to probe and search the hearts of distant galaxies, and then the very centre and the very edges of the whole Universe, but when eventually it was tracked down it turned out in fact to be all the stuff which the equipment had been packed in.

  • Is your universe half empty or half full?
  • by Fortran IV (737299) on Tuesday May 20, 2008 @06:48PM (#23484076) Journal
    No—it can't be true! The Hubble has managed to photograph [hubblesite.org] the Time Cube! [timecube.com] The joke really is on us...
    • Christ on a cracker! Trying to read that timecube site gave me a migrane before I even had to scroll down.
  • When you lose something, it'll always turn up in the last place you look.
  • To save time, and make sure he didn't miss the kickoff with his buddies down at Cosmic Ray's Space Bar, Father Time swept the other half of the now-missing matter under the rug, so Mother Nature wouldn't find it.
  • Good job guys. Now, can we turn that telescope around and look for something useful...like my car keys?

The two most common things in the Universe are hydrogen and stupidity. -- Harlan Ellison

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