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The center of our galaxy

  1. Aug 16, 2005 #1
    I was reading on Space.com about our galaxy and it said that there is a bar of stars, mostly old and red, at the center and at a 45 degree angle from the plane the rest of us are on. In addition to this there is a super-massive black hole. How can the BH be there and the bar of stars, let alone, at a 45?
     
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  3. Aug 16, 2005 #2
    heres the article by the way:
     
  4. Aug 16, 2005 #3

    DaveC426913

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    What is the source of your confusion?

    image of a Bar galaxy


    See attached (very) rough sketch:
     
    Last edited: Nov 28, 2006
  5. Aug 16, 2005 #4
    What he wants to know is how can the Bar of stars exist in such a straight (or what we currently percieve to be straight) co-exist with the presence of a super massive blackhole?

    The one thing i can only think of is that BH's are messy eaters in that the Chew more than they can swallow, the excess material of whatever body they are consuming (in this case and as in most cases, Stars) form an acretion disk the cause for the "jet" that produces in a blackhole (or Pulsar) i dont know, maybe someone here can help me out on this one.
     
  6. Aug 16, 2005 #5

    SpaceTiger

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    There's no problem with having both a supermassive black hole and a bar of stars at the center of the galaxy. This is because the scales are completely different. The event horizon of a supermassive black hole is usually less than the radius of the earth's orbit (~0.00001 parsecs), while stellar bars are usually thousands of parsecs in size and thousands of times more massive. In other words, the bar won't notice that the supermassive black hole is there.

    We think the black hole will notice, though. We're still very much unsure about the evolution of both supermassive black holes and bars, but the popular theories invoke gradual accretion onto the black holes, with the gas being periodically funnelled to the center of the galaxy by instabilities in the surrounding galactic disk. A bar is one such instability and likely plays a role in redistributing matter for accretion onto the supermassive black hole.
     
  7. Aug 16, 2005 #6
    So, it's the enormous distances between the objects that keeps everything okey-doke, right? It's odd to look at the artists rendering of the galaxy and see our approximate location and ALL THE OTHER STUFF that I simply can't make out even on the darkest night. Humbling, but cool.
     
  8. Aug 16, 2005 #7

    SpaceTiger

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    That's right, and the fact that the surrounding stars have enough angular momentum that they won't be dragged into the center on any reasonable timescale. It's likely that supermassive black holes do disrupt (or "eat") some stars, but it probably isn't an amount that would have a noticable effect on the large-scale dynamics.
     
  9. Aug 25, 2005 #8

    DaveC426913

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