What keeps our any galaxy together in one piece?

Discussion in 'Astronomy, Exobiology, & Cosmology' started by Gravage, Apr 5, 2005.

  1. Gravage Registered Senior Member

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    Why all stars just can't escape from the galaxy,what keeps galaxy together,is it the center of galaxy which has enormous concentration of stars,and if it's the center of the galaxy together what keeps this center together-the answer is a central galaxy's supermassive black hole.
    That's my opinion.
    But do scientists know what keeps galaxy from collapsing into a black hole, and what keeps galaxy together from blowing apart of all its parts and stars that than go into intergalactic space-what keeps the balance in any galaxy between collapsing into a central black hole and blowing apart of all of the stars and the entire galaxy?
    Does anyone really know,and have this ever been proven?
    Thanks!
     
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  3. spidergoat pubic diorama Valued Senior Member

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    Um, dark matter/energy?
     
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  5. alteredperception I know not what I do Registered Senior Member

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    thats like asking what keeps the sun from collapsing or blowing apart. its a hydrostatic equilibrium. the gravity balances with the energy output
     
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  7. eburacum45 Valued Senior Member

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    Dark matter certainly seems to be important in the formation of galaxies, causing the thinly spread normal matter to collect in tighter forms than it would have done if there were no dark matter. In that case the Galaxy can be regarded as being held together by Dark matter (whatever it is).
    If Dark matter were more abundant or more massive then perhaps galaxies would be more compact, and more matter would fall into the central hole(s); but even then black holes are small compared to galaxies, and would still eject a considerable portion of this infalling matter on hyperbolic trajectories.
     
  8. Yorda Registered Senior Member

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    Magnetism holds our galaxy together, just as it holds atoms together. Repulsion and attraction... things can't escape or fall together.
     
  9. cato less hate, more science Registered Senior Member

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    Ninjas hold it together! but them damn pirates keep trying to ruin everything =]

    Seriously though, I think it is probably a super-massive black hole.
     
  10. THC Registered Member

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    yeah dude... its just that most galaxies haven't reached the middle of the whirlpool yet.
    if you haven't seen it, find & watch the BBC's Hyperspace series.
     
  11. Avatar smoking revolver Valued Senior Member

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    Our and most other galaxies have a black hole at their centre. The black hole has "ate" all the gas that is in its' reach, so there is a "dead" region around it, it's dormant and not "feeding".
     
  12. Itseemstome Registered Senior Member

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  13. Avatar smoking revolver Valued Senior Member

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    ether is like the elephants on which rests the earth
     
  14. blobrana Registered Senior Member

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    Hum,
    It’s ether or either...

    This is like saying "i wonder why our solar system keeps together in one piece"...

    a) it’s not stable, and has never ever has been
    b) Newtonian physics is all we need, (er, and a bit of `unseen matter` in the galaxies halo to explain the `linear` rotation patterns.)
     
  15. Maddad Time is a Weighty Problem Registered Senior Member

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    The classic answer to what keeps galaxies together is the collective gravity of all of its stars. It gets a bit complicated though. The galaxies rotate faster for their distance from the center than what gravity should allow them. We shrug our shoulders and say there must be more stuff in the galaxies than what we can see if we attribute the motion intirely to gravity. Since we can't see what we believe is there, we call what we think ought to be there dark matter.

    As for why stars don't fly out of the galaxy, they do. Mostly it's the lighter stars that gain orbital momentum from a chance near encounter with a more massive star. The lighter star goes to a greater orbital distance from the galacitic nucleus, and the more massive star drops in closer. Sometimes the lighter stars gains enough orbital speed to leave the galaxy entirely, a process sometimes called evaporation.

    Interestingly, this is why the galactic center has a high density of massive stars. We think the process would result in some of these stars dropping into the central supermassive blackhole, feeding it and making it grow larger.
     
  16. Gravage Registered Senior Member

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    Until,it's proven otherwise,here's what I think:Central supermassive black hole hold the central point of the galaxy where is the greatest/densest concentration of supermassive stars in any galaxy-those supermassive stars(held by ceentral supermassive black hole) because of the great mass of the central region of every galaxy,are keeping all other stars in the galaxy.
     
  17. Yorda Registered Senior Member

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    This is like asking why 'electrons' (satellites) don't leave their orbits or fall on the nucleus. Planets and everything stay on their orbits because of the same reason. Nucleus is not only attractive, but also repulsive, and those two equal forces keep them on their orbits and make them spin. The syncronized spinning creates the illusion of only-attraction (gravity)
     

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