How Much Dark Matter

Discussion in 'Science and Technology' started by Robert_Stephens, Feb 16, 2011.

  1. Robert_Stephens
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    Robert_Stephens BANNED

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    How Much Dark Matter?

    How Much Dark Matter Do Some Galaxies Need? 300 Billion Suns | Dark Matter, Dark Energy | Strangest Things In Space | Space.com

    It appears, what they are calling dark matter, is now being estimated to run at about a mass of some 300 billion sun size volume.

    Active galaxies show the way

    Star formation is especially high within so-called submillimeter galaxies, which are some of the most active stellar cradles in the 13.7-billion-year-old universe. (The galaxies get their name from the emissions we detect from them as they rapidly move away from Earth. The wavelength of the emissions is less than a millimeter long.) In these old, bright galaxies, new stars are created at the rate of up to a few thousand per year. By comparison, the Milky Way produces about 10 stars annually.

    "These are the galaxies that formed when the universe was about 2 or 3 billion years old," Cooray said.

    After measuring the brightness of the galaxies within the patch of sky, the researcher calculated the minimum dark halo mass needed to develop and sustain a submillimeter galaxy when the universe's star formation was at its peak.

    That number, 300 billion solar masses, is substantially less than previous estimates.

    "There could be many reasons for this," Cooray said. For example, "it could be that there are more galaxies in the universe actively undergoing star formation than assumed by current simulations."

    Or it could be something else entirely.

    Whatever the cause, the link between halo mass and star formation will require another look at current theoretical models for these ancient star-forming galaxies, as well as galaxy formation and evolution as a whole, researchers said.

    I find this quite compelling in that it is still a postulate, but plausible since there is no other models to work with.

    Comments welcome.

    Robert
     
  2. waltky
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    waltky Wise ol' monkey Supporting Member

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    Scientists hope to detect that rare event when a particle of dark "stuff" bumps into regular matter...
    :eusa_eh:
    Dark Matter: Experiment to shed light on dark particles
    5 February 2013 - BBC World Service science reporter Rebecca Morelle has been inside the Darkside50 experiment
     
  3. waltky
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    waltky Wise ol' monkey Supporting Member

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    Granny says dat don't look like dark matter to her - dat looks like a copper thing-a-ma-jiggy...
    :eusa_eh:
    Dark matter experiment CDMS sees three tentative clues
    15 April 2013 - Researchers have revealed the first potential hints of the elusive material called dark matter at an underground laboratory in the US.
     

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