back to article Dark matter surveys turn up new satellites … orbiting the Milky Way

Dwarf galaxies circling the Milky Way, some with only a few hundred stars, could yield new hints about dark matter, according to boffins from the University of Cambridge and the Dark Energy Survey. The two groups independently discovered the dwarf galaxies while combing over first year's worth of data published by the Dark …

  1. Duncan Macdonald Silver badge

    If dark matter exists

    If the MOND theory is correct then dark matter need not exist.

    1. Martin Budden

      Re: If dark matter exists

      Unfortunately there is other stuff happening which is impossible under MOND theory.

    2. Destroy All Monsters Silver badge

      Re: If dark matter exists

      MOND is not a theory, just a fancy schoolboy trick of adding another term to the Newtonian equations of motion.

      There might be something to it, but it's unlikely.

  2. Martin Budden
    Joke

    Spray a big bit of outer space with flouro paint: you'll immediately be able to see where the lumps of dark matter are.

  3. Anonymous Coward
    Headmaster

    Get it right

    Just a few hundred stars? Methinks we need a new term.

    What about "midget galaxy?"

    1. VinceH Silver badge

      Re: Get it right

      "Just a few hundred stars? Methinks we need a new term."

      Yes, we don't want the same thing to happen to them that happened to Pluto. Considered a planet for so very long then suddenly demoted to a minor planet. If we call these things galaxies now, that's what'll happen - at some later date they'll be demoted.

      "What about "midget galaxy?""

      Fun-size galaxy?

      1. KR Caddis

        Re: Get it right

        How about "Dwarf"; it seems to follow logically.

      2. Snowball Solar System

        Re: Get it right

        Baryonoic Dark Matter:

        I suggest 'globule clusters' for gravitationally-bound (Boki) globules which themselves are composed of gravitationally-bound aggregates of H2 & He at such that their (luminous) stellar metallicity has 'snowed out' to the solid state, sequestering luminous metallicity from detection into icy chondrules, rendering the remaining H2 & He invisible and thus 'dark'. (Molecular hydrogen and helium don't absorb electromagnetic radiation below ultraviolet frequencies, rendering it essentially dark.)

        The familiar (Bok) globules of giant molecular clouds are globules in the 'excited state', in which a portion of their stellar metallicity has been sublimed into the gaseous state by exposure to stellar radiation, rendering Bok globules opaque and thus visible. And gaseous stellar metallicity raises the sound crossing time (lowers the speed of sound), promoting Jeans instability. So stellar radiation in the disk plane can cause CDM globule clusters to 'go nuclear' and convert to star clusters.

        1. KR Caddis

          Re: Get it right

          I generally agree, however if they are Boki globules why not call them so and be done with it?

    2. Anonymous Coward
      Anonymous Coward

      Re: Get it right

      The Galaxy Mini?

      1. Graham Marsden
        Coat

        Re: Get it right

        "Compact"? "Bijou"?

    3. Brewster's Angle Grinder Silver badge

      Re: Get it right

      Globular cluster?

    4. Primus Secundus Tertius Silver badge

      Re: Get it right

      As I understand it, many a globular cluster has more than "a few hundred stars".

      How about exo-cluster, rather than some sort of downsized galaxy?

      1. Anonymous Coward
        Anonymous Coward

        Re: Get it right

        "How about exo-cluster..."

        Pocket Cluster!

  4. Andy The Hat Silver badge

    Re: Get it right

    What about 'some stars'?

  5. adnim Silver badge

    As I understand things

    The Higgs field cannot be massless because the Higgs has mass, therefore the whole Universe even the quantum vacuum has a mass associated with the Higgs field.

    The Higgs boson interacts with matter to give mass to other particles.

    The Higgs boson is an excitation in the Higgs field producing a mass of approx 126GeV

    Every particle with mass interacts with a Higgs boson of mass 126GeV

    So add 126GeV to the mass of every particle in the Universe (most of them are in and around galaxies)

    Does this not account for Dark matter, or at least some of the extra mass we cannot detect?

    Just a though I am a hobbyist with interest not a particle physicist or cosmologist with a PhD

    Need an "I am just guessing here" icon

    1. Ashton Black

      Re: As I understand things

      ... and as I understood it, the Higgs bosons very quickly degenerated into the Higgs Field soon after the Big Bang but before the "quark soup" period of inflation. This would lead one to suggest it's the integration with the field rather than boson, that gives particles their respective masses.

      I use the same caveats as you and would welcome a better explanation from a learned commenter.

    2. Bluewhelk

      Re: As I understand things

      Doesn't work like that I'm afraid.

      Fields are areas of space where there is a potential difference of some sort, you gain or lose energy when moving a particle through the field that interacts with it. For example with two parallel plates with extra electrons on one of them there will be an electrostatic field between the plates the electrons will 'want' to move to the other plate to balance things out, you can extract the energy by moving half the electrons to the other plate. There isn't anything in the gap as such, the electrons are stuck on the plate.

      Secondly, I think that Higgs bosons are pretty rare in the universe these days, it took the LHC a lot of effort to create even the few it needed to detect them and they decayed pretty quickly. Also the Higgs is very heavy at 126GeV, electrons have a rest mass of about 0.5MeV and hadron type particles like protons are about 1Gev, even if you only stuck Higgs to just these you'd end up with way too much mass.

      Like yourself I'm only an amateur in this area and I may be a bit off base w.r.t the field side of things.

      Edit: @Ashton Black - Yes, like you said.

      1. Andy E
        WTF?

        Re: As I understand things

        How can the Higgs boson interact with ordinary matter when it decays so quickly?

        I'm still trying to get my head around how the Higgs boson and/or the Higgs field gives other particles mass.

  6. hammarbtyp Silver badge

    PC

    Surely they are "star challenged" galaxies..

  7. 2+2=5 Silver badge

    I ain't no cosmologist...

    But if normal matter is just 5% of the mass of universe and therefore dark matter is the remaining 95%, shouldn't there be a lot of dark matter a hell of a lot closer than 100K light years?

    Now, I know we can't see it - for obvious reasons (geddit) - but shouldn't the gravitational effect be more noticeable?

    1. Ashton Black

      Re: I ain't no cosmologist...

      It's actually the other way around. It's the gravitation on large scale structure of the universe that they noticed that led the scientists to conclude that there wasn't enough visible mass to account for it and in addition Dark Matter accounts for about 28% (approx.) of the total matter/energy in the universe, but coupled with Dark Energy adds up to the 95% you mentioned.

    2. Someonehasusedthathandle

      Re: I ain't no cosmologist...

      Vaguely relevant xkcd - especially the alt text

      http://xkcd.com/1489/

      1. Martin Budden
        Headmaster

        Re: I ain't no cosmologist...

        title text

  8. Infernoz Bronze badge
    Meh

    100,000 Light Years is time in the past too, relative to us.

    So we are seeing about 100,000 year old electromagnetic radiation (with allowance for distance variance and electromagnetic radiation bending by gravity), so do these objects still exist intact?

    A lot could happen in that time!

  9. Anonymous Coward
    Anonymous Coward

    What's with

    all the anonymised stars and galaxies in the photo? They scared to be recognised?

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