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Two Big Dark Matter Experiments Gain US Support

Posted by Soulskill on from the stuff-that-dark-matters dept.

Graculus writes: The Department of Energy and the National Science Foundation announced on Friday that they will try to fund two major experiments to detect particles of the mysterious dark matter whose gravity binds the galaxies instead of just one. The decision allays fears that the funding agencies could afford only one experiment to continue the search for so-called weakly interacting massive particles, or WIMPs.

7 of 37 comments (clear)

  1. Re:Of course it won't be settled then by joh · · Score: 3, Insightful

    "A bit mysterious" is the understatement of the day... Still, it's one of the very few actual observable things that could further some fundamental new understanding of physics.

  2. I don't see what you are saying by pavon · · Score: 4, Insightful

    We'll have more information about the gravity attributes and locations of dark matter,

    Both of these experiments aim to detect collisions of dark matter particles with their respective detectors, and if found give an estimate of the particles energy. Neither are astronomical surveys that would tell us anything about the gravitational properties or distribution of dark matter.

    1. Re:I don't see what you are saying by lgw · · Score: 2

      Clearly, we'd know something about the distribution of dark matter if the detector encountered a particle: 1 particle, right here. That may sound like a joke, but we know so little that any sort of estimate of dark matter density near Earth would tell us something interesting about its distribution (presumably affected only by gravity, but we don't really know beyond "not affected by EM").

      --
      Socialism: a lie told by totalitarians and believed by fools.
  3. Huh? by Anonymous Coward · · Score: 2, Insightful

    What are you TALKING about? Your username may be "i kan reed" but it seems you did not choose to read the article.

  4. Re:Dark Matter == Measurement Uncertainty? by Anonymous Coward · · Score: 2, Informative

    Well, you can look at error bars on galaxy rotation curve results like this, which is old enough to end up in an intro cosmology course. If it were just visible matter, it would be the curve labeled "disk". If you add the curve "halo" you get the total, with the small measurement error bars shown. Surveys like this show the limits of such halos being just from compact but dark objects.

  5. Re:Dark Matter == Measurement Uncertainty? by MrFlibbs · · Score: 2

    There are several data sets that suggest the presence of Dark Matter:
        1) Orbital velocities of galaxies within a cluster are too high -- the galaxies should fly apart unless much more mass is present.
        2) Observed rotational velocities of edge-on galaxies are wrong: stars near the edge rotate too fast -- unless there's a cloud of mass beyond the observed disk.
        3) Gravitational lensing effects are too strong for the observed mass of the lensing clusters.
        4) Numerical simulations modeling the Big Bang up to present times work well only if Dark Matter is assumed.

    There may be other data sets, but these are the ones that were presented in the Coursera class I took last year titled, "Galaxies and Cosmology".

  6. Re:Dark Matter == Measurement Uncertainty? by painandgreed · · Score: 2

    And on top of that, every other explaination that people have come up with to explain those data sets has failed.

    MOND - the idea that gravity has some extra factor that kicks in on galactic scale has yet to provide even a hypothetical answer to be tested. Last I heard, it gets complicated so fast that they haven't even been able to produce a hypothetical gravitational equation that would explain orbital velocities of galaxies let alone the other observed data.

    That the extra matter is out there in more mundane forms such as dim stars or jupiter like orphan planets has been tested since they first started seeing these obeservations, and all tests so far have shown that if that was the case, they should be able top detect it but haven't.

    Somebody once made a comment on /. about just because we put out cat food and it is disappearing, it doesn't mean there is a cat in the house that nobody has seen. However, at this point, the cat food is being eaten, the litter box is being used, something is playing with the cat toys, and if you knock on the walls, you can hear something go "meow". It still may not be the case that there is a cat we've never seen living in the house, but if so, the new answer is much stranger and more complicated.