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Thread: Super massive black holes

  1. #1 Super massive black holes 
    Forum Professor leohopkins's Avatar
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    Simple question. Is our galaxy the accretion disc of the super massive black hole?


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  3. #2 Re: Super massive black holes 
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    Quote Originally Posted by leohopkins
    Simple question. Is our galaxy the accretion disc of the super massive black hole?
    You will have to be precise as to the definition of accretion disk. In any case there is a massive black hole at the center of the galaxy. The accretion disk usually refers to nearby stuff revolving around the black hole at very high speed.


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  4. #3 Re: Super massive black holes 
    Moderator Moderator Dishmaster's Avatar
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    Quote Originally Posted by leohopkins
    Simple question. Is our galaxy the accretion disc of the super massive black hole?
    Simple answer: No.
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  5. #4 Reply to is the center of our galaxy a black hole. 
    Forum Freshman zazzerak's Avatar
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    that is very popular theory but one the better explains the continuing acceleration of the seperating solar systems that the center of our universe is just a large mass of Dark matter which cannot be seen accept for by locating it's e.m. radiation field. Many studies support this theory and it also explains why the galaxy doesn't fling apart into millions of pieces.
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  6. #5  
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    You seem to be confusing dark matter, which pervades the galaxy, and a black hole at the center.
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  7. #6 Re: Reply to is the center of our galaxy a black hole. 
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    Quote Originally Posted by zazzerak
    that is very popular theory but one the better explains the continuing acceleration of the seperating solar systems that the center of our universe is just a large mass of Dark matter which cannot be seen accept for by locating it's e.m. radiation field. Many studies support this theory and it also explains why the galaxy doesn't fling apart into millions of pieces.
    It is its essence that the hypothetical Dark Matter is invisible. Therefore, it does not have or generate an EM field. The only chance to indirectly probe it is to study its gravitational influence.
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  8. #7 Reply 
    Forum Freshman zazzerak's Avatar
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    I'm sorry I messed up. The E.M. field that dark matter generates is the reason you can't see it not the reason you can. yes you're right it is observed through it's gravitional force.
    Any way, what I was saying earlier was that one theory is that at the center of our galaxy is a large mass of Dark matter rather than a black hole. they have extremly powerful gravitational pull but it's weak enough so that the expansion of the galaxy occurs just at a much slower rate. if there were a black hole at the center of our galaxy we would most likely see a steady decrease in the velocity of the galaxies seperation.
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    What is your source for the theory that the center is dark matter rather than a black hole? The central mass is many millions of solar masses in an extremely small volume - only a black hole fits that description. The dark matter in the galaxy is supposed to be spread throughout.
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  10. #9  
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    The dark matter that is postulated to fill the Milky Way is not responsible for the Black Hole. these two things are entirely unrelated. But the Dark Matter can be used to explain the observed ration curve, i.e. the tangent velocity of stars vs. their distance from the galactic centre. The Black Hole is not responsible for this rotation.
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  11. #10 Reply 
    Forum Freshman zazzerak's Avatar
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    I'm not saying that dark matter caused a black hole nor that they are in any way related. I'm saying that D.M. replaces the black hole at the center of our galaxy. there is no black hole at the center of our galaxy, it is a super mass of dark matter.
    If there were a black hole at the center of our galaxy we would see photons steadily being pulled towards that as well as celestial bodies. We don't see that, we only see the celestial bodies being pulled towards the center of the galaxy. and it is weak enough that the galaxy is slowly drifting apart. were it a black hole we would not see these effects.
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  12. #11 Re: Reply 
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    Quote Originally Posted by zazzerak
    I'm not saying that dark matter caused a black hole nor that they are in any way related. I'm saying that D.M. replaces the black hole at the center of our galaxy. there is no black hole at the center of our galaxy, it is a super mass of dark matter.
    If there were a black hole at the center of our galaxy we would see photons steadily being pulled towards that as well as celestial bodies. We don't see that, we only see the celestial bodies being pulled towards the center of the galaxy. and it is weak enough that the galaxy is slowly drifting apart. were it a black hole we would not see these effects.
    How can we see photons being pulled in? We see photons when they hit the earth (or Hubble). We can see the accretion disk because it is emitting photons in all directions as it heats up going into the black hole.
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  13. #12 reply 
    Forum Freshman zazzerak's Avatar
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    we can see the photons being pulled in by observing visual rdiations... light bascially. we watch the light getting sucked in.
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  14. #13 Re: Super massive black holes 
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    Quote Originally Posted by leohopkins
    Simple question. Is our galaxy the accretion disc of the super massive black hole?
    It has been said that SMBH's are the seeds around which galaxies form. Just looking at a spiral galaxy it does give the impression that the central mass is dragging the rest around, and it is central mass rather than just a large black hole in the centre. It is plausible over time that the mass does spread out as it rotates, as in spiral arms.
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  15. #14 Re: reply 
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    Quote Originally Posted by zazzerak
    we can see the photons being pulled in by observing visual radiations... light bascially. we watch the light getting sucked in.
    Photons do not get sucked in though their path would curve in passing close to the black hole. A photon that travels into the hole will not come out again.

    BH's have busy and quiet periods, the latter being when they have sucked in all matter within reach of them, which is the current situation of our galaxy's SMBH.

    DM is said to form in large clusters only, which would mean that while it could be sucked into a black hole if too close, it is not going to naturally form a black hole, or any very dense DM area.
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  16. #15  
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    We detect strong radiation coming from the region we identify as the nucleus of the Milky Way. This radiation is comprised of radio and X ray wavelengths. This can only be explained by intense friction of normal matter within an accretion disc around the galactic nucleus. Dark matter does not experience that kind of friction. It does not generate any detectable electromagnetic radiation - only gravitation. So, in this way we "see" matter like gas and stars being disrupted by the tidal forces of a strong concentration of matter before they fall into the inner zone of that nucleus.

    The observations of the galactic nucleus clearly show stars on orbits around it from which we can derive the mass density inside these orbits. From all that we know, there is no other configuration thinkable than a Black Hole that can incorporate so much mass within the volume probed. If the mass that produces it is comprised of Dark or normal baryonic matter is irrelevant. Nevertheless, if Dark matter really exists, it must be distributed like a halo around the Milky Way. A strong concentration towards the galactic nucleus contradicts the observations of orbiting visible matter throughout the galaxy.
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  17. #16 Re: reply 
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    Quote Originally Posted by zazzerak
    we can see the photons being pulled in by observing visual rdiations... light bascially. we watch the light getting sucked in.
    It sounds like you are saying photons, as they move in some direction, emit photons in all directions! This is weird physics to say the least!
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