Chief Elder Osiris : Hubble Finds Ring of Dark Matter

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  1. Chief Elder Osiris

    Chief Elder Osiris Well-Known Member MEMBER

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    Beloved, there is more to this than meet the Human Being Eye.

    HILY
    Osiris


    News Release Number: STScI-2007-17 Hubble Finds Ring of
    Dark Matter The
    full news release story: [c] View
    this image
    <http://hubblesite.org/newscenter/archive/releases/2007/17/image/a/>
    Astronomers using NASA's Hubble Space Telescope have discovered a
    ghostly ring of dark matter that formed long ago during a titanic
    collision between two massive galaxy clusters.

    The ring's discovery is among the strongest evidence yet that dark
    matter exists. Astronomers have long suspected the existence of the
    invisible substance as the source of additional gravity that holds
    together galaxy clusters. Such clusters would fly apart if they relied
    only on the gravity from their visible stars. Although astronomers don't
    know what dark matter is made of, they hypothesize that it is a type of
    elementary particle that pervades the universe.

    "This is the first time we have detected dark matter as having a unique
    structure that is different from both the gas and galaxies in the
    cluster," said astronomer M. James Jee of Johns Hopkins University in
    Baltimore, Md., a member of the team that spotted the dark-matter ring.

    The researchers spotted the ring unexpectedly while they were mapping
    the distribution of dark matter within the galaxy cluster Cl 0024+17
    (ZwCl 0024+1652), located 5 billion light-years from Earth. The ring
    measures 2.6 million light-years across. Although astronomers cannot see
    dark matter, they can infer its existence in galaxy clusters by
    observing how its gravity bends the light of more distant background
    galaxies.

    "Although the invisible matter has been found before in other galaxy
    clusters, it has never been detected to be so largely separated from
    the hot gas and the galaxies that make up galaxy clusters," Jee said.
    "By seeing a dark-matter structure that is not traced by galaxies and
    hot gas, we can study how it behaves differently from normal matter."

    During the team's dark-matter analysis, they noticed a ripple in the
    mysterious substance, somewhat like the ripples created in a pond from
    a stone plopping into the water.

    "I was annoyed when I saw the ring because I thought it was an artifact,
    which would have implied a flaw in our data reduction," Jee explained.
    "I couldn't believe my result. But the more I tried to remove the ring,
    the more it showed up. It took more than a year to convince myself that
    the ring was real. I've looked at a number of clusters and I haven't
    seen anything like this."

    Curious about why the ring was in the cluster and how it had formed, Jee
    found previous research that suggested the cluster had collided with
    another cluster 1 to 2 billion years ago. The research, published in
    2002 by Oliver Czoske of the Argeleander-Institut fur Astronomie at the
    Universitat Bonn, was based on spectroscopic observations of the
    cluster's three-dimensional structure. The study revealed two distinct
    groupings of galaxies clusters, indicating a collision between both
    clusters.

    Astronomers have a head-on view of the collision because it occurred
    fortuitously along Earth's line of sight. From this perspective, the
    dark-matter structure looks like a ring.

    Computer simulations of galaxy cluster collisions, created by the team,
    show that when two clusters smash together, the dark matter falls to
    the center of the combined cluster and sloshes back out. As the dark
    matter moves outward, it begins to slow down under the pull of gravity
    and pile up, like cars bunched up on a freeway.

    "By studying this collision, we are seeing how dark matter responds to
    gravity," said team member Holland Ford of Johns Hopkins University.
    "Nature is doing an experiment for us that we can't do in a lab, and it
    agrees with our theoretical models."

    Dark matter makes up most of the universe's material. Ordinary matter,
    which makes up stars and planets, comprises only a few percent of the
    universe's matter.

    Tracing dark matter is not an easy task, because it does not shine or
    reflect light. Astronomers can only detect its influence by how its
    gravity affects light. To find it, astronomers study how faint light
    from more distant galaxies is distorted and smeared into arcs and
    streaks by the gravity of the dark matter in a foreground galaxy
    cluster, a powerful trick called gravitational lensing. By mapping the
    distorted light, astronomers can deduce the cluster's mass and trace
    how dark matter is distributed in the cluster.

    "The collision between the two galaxy clusters created a ripple of dark
    matter that left distinct footprints in the shapes of the background
    galaxies," Jee explained. "It's like looking at the pebbles on the
    bottom of a pond with ripples on the surface. The pebbles' shapes
    appear to change as the ripples pass over them. So, too, the background
    galaxies behind the ring show coherent changes in their shapes due to
    the presence of the dense ring."

    Jee and his colleagues used Hubble's Advanced Camera for Surveys to
    detect the faint, distorted, faraway galaxies behind the cluster that
    cannot be resolved with ground-based telescopes. "Hubble's exquisite
    images and unparalleled sensitivity to faint galaxies make it the only
    tool for this measurement," said team member Richard White of the Space
    Telescope Science Institute in Baltimore.

    Previous observations of the Bullet Cluster with Hubble and the Chandra
    X-ray Observatory presented a sideways view of a similar encounter
    between two galaxy clusters. In that collision, the dark matter was
    pulled apart from the hot cluster gas, but the dark matter still
    followed the distribution of cluster galaxies. Cl 0024+17 is the first
    cluster to show a dark matter distribution that differs from the
    distribution of both the galaxies and the hot gas.

    The team's paper will appear in the June 1 issue of the Astrophysical
    Journal.
    CONTACT
    Donna Weaver/Ray Villard
    Space Telescope Science Institute, Baltimore, Md.
    410-338-4493/4514

    Richard White
    Space Telescope Science Institute, Baltimore, Md.
    (phone) 410-338-4899
    (e-mail) [email protected]

    Myungkook James Jee
    Johns Hopkins University, Baltimore, Md.
    (phone) 410-516-5497
    (e-mail) [email protected]

    Lisa De Nike
    Johns Hopkins University, Baltimore, Md.
    (phone) 443-287-9906
    (e-mail) [email protected]
    ---
    http://hubblesite.org/newscenter/archive/releases/2007/17/full/
     
  2. emanuel goodman

    emanuel goodman Well-Known Member MEMBER

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    Dark matter



    Greetings dear elder. Gas and galaxies are physical properities. So if the dark matter appears to be visible it must be giving off some sort of energy in order to appear visible. Is this dark matter a form of galactic melanin used to bond and hold physcial bodies in orbit of thier star,much like the melanin that is present after the big bang when the sperm hits the ovam and bodies that begin to form and orbit around the ovam?
     
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