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Space ISS

Mystery Signal Could Be Dark Matter Hint In ISS Detector 55

Posted by samzenpus from the filling-in-space dept.
astroengine writes Analysis of 41 billion cosmic rays striking the Alpha Magnetic Spectrometer particle detector aboard the International Space Station shows an unknown phenomena that is "consistent with a dark matter particle" known as a neutralino, researchers announced Thursday. Key to the hunt is the ratio of positrons to electrons and so far the evidence from AMS points in the direction of dark matter. The smoking gun scientists look for is a rise in the ratio of positrons to electrons, followed by a dramatic fall — the telltale sign of dark matter annihilating the Milky Way's halo, which lies beyond its central disk of stars and dust. However, "we have not found the definitive proof of dark matter," AMS lead researcher Samuel Ting, with the Massachusetts Institute of Technology and CERN in Switzerland, wrote in an email to Discovery News. "Whereas all the AMS results point in the right direction, we still need to measure how quickly the positron fraction falls off at the highest energies in order to rule out astrophysical sources such as pulsars." But still, this new finding is a tantalizing step in the dark matter direction.
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Mystery Signal Could Be Dark Matter Hint In ISS Detector More

Mystery Signal Could Be Dark Matter Hint In ISS Detector

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  • ISIS is in space? (Score:1, Offtopic)

    by ka9dgx ( 72702 )

    How the heck did ISIS make it up into orbit to attack the space station? You can't trust the Russkies, can you?

    Next thing you know ISIS will be on the moon, and we'll have to bomb them. ;-)

  • >> the telltale sign of dark matter annihilating the Milky Way's halo

    Sooooo when did dark matter become anti-matter? Or am I missing something?

    • Re: (Score:1)

      by ls671 ( 1122017 )

      Do you need anti-matter for "annihilating the Milky Way's halo"?

      Dark matter could be made of black holes:

      "There have been many candidates for this theorized "dark" matter, and in truth it is probably some combination of them: hot or cold gas, neutron stars, white or brown dwarfs, exotic particles and, yes, even black holes!"

      https://van.physics.illinois.e... [illinois.edu]

      • Re:Huh? (Score:5, Informative)

        by Bengie ( 1121981 ) on Thursday September 18, 2014 @06:26PM (#47941191)
        In the past year, all of those have been eliminated. Dark Matter has to be something that doesn't not interact with light in any way except via gravity. I'm pretty sure "gas" interacts with light. Black holes is the only thing that fits this restriction, but the gravitational gradient would be too much, and would require 80% of the universes mass to be tied up in black-holes at the edge of galaxies.

        • Re:Huh? (Score:4, Informative)

          by Anonymous Coward on Thursday September 18, 2014 @06:45PM (#47941291)

          In the past year, all of those have been eliminated.

          Most of those were weakened, if not eliminated over a decade ago, going back almost to some early surveys in the 90s. Not just in the past year. More and more studies keep reducing upper bounds on the number of such objects, but for some time that upper bound has been too low.

          Dark Matter has to be something that doesn't not interact with light in any way except via gravity.

          Dark matter can still interact with light, it just must do so weakly in a way that would match current observations. There are several detectors looking for various dark matter candidates passing through the detectors that would involve electromagnetic interaction, but such processes would be so dim in outer space that you couldn't see them from any distance.

          I'm pretty sure "gas" interacts with light.

          It also is something that has been mapped out a lot, and is baryonic.

          , but the gravitational gradient would be too much, and would require 80% of the universes mass to be tied up in black-holes at the edge of galaxies.

          The gradient is not a problem, nor would they all be right at the edge of the galaxy. A model using a gas of very small black holes spread through out the galaxy and halo would explain rotation curves just fine, as would it explain other things like gravitational lensing if there were clouds of black holes in certain places between galaxies. The problem with black holes is not that they couldn't explain the missing gravity source, but that they would have been observerable in various surveys specifically looking for them and were not.

        • Re: (Score:2)

          by ls671 ( 1122017 )

          I never mentioned large black holes and I was using the quote to demonstrate that we still do not know what is going on really yet.

          Anyway, this seems recent enough ( April 30, 2014):
          "Black hole atoms now join a long list of candidates for dark matter particles, from supersymmetric neutralinos, WIMPs and axions to warm sterile neutrinos and many more, Dokuchaev told Space.com. Verifying whether any of them is the real deal will require catching one first, he added."

          http://www.space.com/25691-dar... [space.com]

      • Re: (Score:2, Informative)

        by Anonymous Coward

        You should have read the sentences right after where your quote stops:

        "But we've been able to eliminate most of these as the primary variety in one way or another. If black holes constituted all of dark matter, for instance, we would expect to see gravitational lensing (the bending of light as it passes massive objects) when we look through the halo of our own galaxy at stars in other galaxies because we would expect there to be many black holes in that halo. We do not see such lensing, so we conclude that

      • Re: (Score:2, Interesting)

        by slashmydots ( 2189826 )
        You forgot the most realistic and easily proven dark matter theory. It's a math error! If the Star Ship Enterprise can't estimate total matter in the entirety of the universe, I don't think a Xeon can. You have to compensate for billion of years of light delay over an even scale while space is expanding the entire time that the light is traveling through it and be flawlessly accurate on the counts of individual atoms. You get one single thing wrong like mass vs perceived light bending around a black hole

    • Re: (Score:2)

      by radtea ( 464814 )

      Sooooo when did dark matter become anti-matter? Or am I missing something?

      Probably pretty much everything.

      Matter and anti-matter are--up to a flip in charge and parity--the same thing. That is, if you take an electron (a matter particle), flip its charge and look at in a mirror you'll see a positron (an anti-matter particle).

      So it is actually perfectly consistent, logically if not linguistically, for dark matter to be entirely anti-matter.

      Exotic dark matter can also produce anti-matter when its particles collide with each other, which is what this report seems to be about. The si

    • Re:Huh? (Score:5, Informative)

      by iggymanz ( 596061 ) on Thursday September 18, 2014 @07:19PM (#47941459)

      The hypothetical "neutralino" is a family of four particles the lightest of which is considered to be a dark matter candidate. Neutralinos are their own antiparticles (similar to how photons are), and a pair of them can sometimes annihilate to form other matter-antimatter pairs of particles.

    • I think they meant "annihilating in." Dark matter should have both anti- and regular variants, which would annihilate with each other, potentially producing an observable signal. Actually, the neutralino they're discussed is probably a Marjorana fermion, which is its own anti-particle.

  • Does this mean they'll find the gravioli next?

  • Are we talking about the fountain of 511keV positron/electron annihilation photons from the galactic poles, or are we talking some exotic gammas from an Neutralino annihilation?

    Inquiring minds want to know... :)

    • The smoking gun scientists look for is a rise in the ratio of positrons to electrons, followed by a dramatic fall

      Enquiring minds should read the summary ;)

  • the telltale sign of dark matter annihilating the Milky Way's halo

    Is that supposed to be "annihilating in the Milky Way's halo"?

  • The summary makes little sense, but I suspect this is because nothing was really found. Awake me when you will have some real news.
  • Which would be the biggest news for physics: A discovered candidate for dark mattery or discovery of a particle predicted by supersymmetry? I thought evidence from the LHC was casting doubt on many supersymmetry theories? Also Samuel Ting is fairly old which is a shame because it might be unlikely he could live long enough to be one of those rare scientists who are awarded multiple Nobel Prizes.

  • The fact is that we have too little evidence to guide us, and we can all speculate to some extent. My favourite, based on nothing more than my own wishful thinking, really, is that dark matter consists of not just 1 kind of particle, but of a whole 'phylum' (to borrow a word from biology) of particles that interact with themselves much like the particles we know; there may be several phylums (or phyla, if you prefer). The reason I like the idea is simply that it allows me to fantasize about a kind of parall

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