MilkyWay Galaxy May Be 50% Larger Than We Thought

Discussion in 'Science and Nature' started by NorseMythology, Mar 19, 2015.

  1. You should put quotes and discussion

    Not everyone can use links. Like people with shitty phones

    -yuri
     
  2. he Milky Way galaxy is at least 50
    percent larger than is commonly
    estimated, according to new findings that
    reveal that the galactic disk is contoured
    into several concentric ripples. The research,
    conducted by an international team led by
    Rensselaer Polytechnic Institute Professor
    Heidi Jo Newberg, revisits astronomical data
    from the Sloan Digital Sky Survey which, in
    2002, established the presence of a bulging
    ring of stars beyond the known plane of the
    Milky Way.
    "In essence, what we found is that the disk of
    the Milky Way isn't just a disk of stars in a
    flat plane -- it's corrugated," said Heidi
    Newberg, professor of physics, applied physics,
    and astronomy in the Rensselaer School of
    Science. "As it radiates outward from the sun,
    we see at least four ripples in the disk of the
    Milky Way. While we can only look at part of
    the galaxy with this data, we assume that this
    pattern is going to be found throughout the
    disk."
    Importantly, the findings show that the
    features previously identified as rings are
    actually part of the galactic disk, extending
    the known width of the Milky Way from
    100,000 light years across to 150,000 light
    years, said Yan Xu, a scientist at the National
    Astronomical Observatories of China (which is
    part of the Chinese Academy of Science in
    Beijing), former visiting scientist at
    Rensselaer, and lead author of the paper.
    "Going into the research, astronomers had
    observed that the number of Milky Way stars
    diminishes rapidly about 50,000 light years
    from the center of the galaxy, and then a ring
    of stars appears at about 60,000 light years
    from the center," said Xu. "What we see now is
    that this apparent ring is actually a ripple in
    the disk. And it may well be that there are
    more ripples further out which we have not
    yet seen."
    The research, funded in part by the National
    Science Foundation and titled "Rings and
    Radial Waves in the Disk of the Milky Way,"
    was published today in the Astrophysical
    Journal. Newberg, Xu, and their collaborators
    used data from the Sloan Digital Sky Survey
    (SDSS) to show an oscillating asymmetry in
    the main sequence star counts on either side
    of the galactic plane, starting from the sun
    and looking outward from the galactic center.
    In other words, when we look outward from the
    sun, the mid-plane of the disk is perturbed up,
    then down, then up, and then down again.
    "Extending our knowledge of our galaxy's
    structure is fundamentally important," said
    Glen Langston, NSF program manager. "The
    NSF is proud to support their effort to map the
    shape of our galaxy beyond previously
    unknown limits."
    The new research builds upon a 2002 finding
    in which Newberg established the existence of
    the "Monoceros Ring," an "over-density" of
    stars at the outer edges of the galaxy that
    bulges above the galactic plane. At the time,
    Newberg noticed evidence of another over-
    density of stars, between the Monoceros Ring
    and the sun, but was unable to investigate
    further. With more data available from the
    SDSS, researchers recently returned to the
    mystery.
    "I wanted to figure out what that other over-
    density was," Newberg said. "These stars had
    previously been considered disk stars, but the
    stars don't match the density distribution you
    would expect for disk stars, so I thought 'well,
    maybe this could be another ring, or a highly
    disrupted dwarf galaxy."
    When they revisited the data, they found four
    anomalies: one north of the galactic plane at
    2 kilo-parsecs (kpc) from the sun, one south
    of the plane at 4-6 kpc, a third to the north at
    8-10 kpc, and evidence of a fourth to the
    south 12-16 kpc from the sun. The Monoceros
    Ring is associated with the third ripple. The
    researchers further found that the oscillations
    appear to line up with the locations of the
    galaxy's spiral arms. Newberg said the
    findings support other recent research,
    including a theoretical finding that a dwarf
    galaxy or dark matter lump passing through
    the Milky Way would produce a similar
    rippling effect. In fact, the ripples might
    ultimately be used to measure the lumpiness
    of dark matter in our galaxy.
    "It's very similar to what would happen if you
    throw a pebble into still water -- the waves
    will radiate out from the point of impact," said
    Newberg. "If a dwarf galaxy goes through the
    disk, it would gravitationally pull the disk up
    as it comes in, and pull the disk down as it
    goes through, and this will set up a wave
    pattern that propagates outward. If you view
    this in the context of other research that's
    emerged in the past two to three years, you
    start to see a picture is forming."
    The research was funded by the NSF, as well
    as the Chinese National Science Foundation
    and the National Basic Research Program of
    China.
    Newberg currently researches the structure and
    evolution of our own galaxy, using stars as
    tracers of the galactic halo and disks. These
    stars in turn are used to trace the density
    distribution of dark matter in the Milky Way.
    She has been a participant of the Sloan Digital
    Sky Survey and is currently head of
    participants in LAMOST U.S., a partnership
    allowing U.S. astronomers to take part in a
    survey of more than 7 million stars by the
    Large Sky Area Multi-Object Fiber
    Spectroscopic Telescope in China (LAMOST).
     
  3. Idk why but thats what happens when i paste on my phone. Takes too much effort to fix it all on my phone too... sorry its the best i can do.
     
  4. So they say the fact that we might not see all the stars means the galaxy might be bigger?

    I think the waves shoulda been assumed to exist already.

    Afterall we see this exact wave/ripple effect in our own solar system. Saturn's rings are pretty much a mini galaxy from the perspective of physics.

    I would even bet money that we will discover that galaxies orbit super galaxies in the same fassion, and that these same ripple and wave effects will be observed.

    I question what dark energy is. It seems counter intuitive, as if there is an obvious answer that we are all missing.

    -yuri
     

  5. You are describing 'superclusters' perhaps
     
  6. more like hypothesizing

    To me, there is no reason to believe gravity doesn't work the same way on a macro scale. I could be wrong.

    Dark energy doesnt make sense. Unless its the opposite force to gravity.

    -yuri
     
  7.  
    http://www.sciencedaily.com/releases/2015/03/150310091356.htm
     
    We have small galaxies orbiting us.. and our galaxy is part of the local group which is part of the Virgo supercluster which is now part of the Laniakea supercluster. Our groups are all moving in space, orbiting within and around one another.
     
     
    There are 2 ways to look at dark energy. First, it is dark because it doesn't interact with the light in the universe.. and second, because it is unknown to us. The second reason is mostly what is referred to when scientists talk about dark energy.. energy that is still unknown to us.
     
    So when they say that dark energy causes something, such as expansion of the universe, they are saying that whatever the energy is that is driving it is simply unknown to us still. We can see the effects of it, just can't see the energy itself.. kind of like when you see wind blowing a flag, you see the flag moving but you don't see the wind.
     

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