Hard Light Productions Forums
Off-Topic Discussion => General Discussion => Topic started by: Flipside on June 12, 2013, 11:26:08 am
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http://www.bbc.co.uk/news/science-environment-22874192
Massive black hole goes dormant after big meal, causing some interest in Astronomical/Physical circles :)
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Slow twitch eater.
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I find it interesting because it's not as if a Black Hole can actually do anything about its mass, and therefore its gravitational pull, so this must, in some way, be related to a lack of material being consumed for whatever reason. Whether that is something to do with the physics of the hole, or the physics of the area around it, I don't know.
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That, or something plugged the other end. :nervous:
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That, or something plugged the other end. :nervous:
(http://i74.photobucket.com/albums/i266/Chiprocks1/Smilies/0%20All%20Smilies/headslap2.gif)
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Or... someone is using it. :warp::warp::warp: Dun dun dun!
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That, or something plugged the other end. :nervous:
Well it made me smile :)
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Maybe it is the end of its hibernation cycle and soon it will once more be wandering the Universe... :nervous:
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Maybe the black hole is actually a giant hermit crab's "shell", and it got sick of stars getting stuck in it's joints, so it closed the hatch, so to speak. ;7
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I find it interesting because it's not as if a Black Hole can actually do anything about its mass, and therefore its gravitational pull, so this must, in some way, be related to a lack of material being consumed for whatever reason. Whether that is something to do with the physics of the hole, or the physics of the area around it, I don't know.
There's zero mystery here. The accretion disk has just temporarily worn out of matter to feed the BH. The BH is still spinning like crazy and still with its huge mass and gravity pull. It will "wake up" again in the near or far future.
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As the article states, there's been no visible drop in star production in the area the Black Hole exists in, I don't think Astronomers would be surprised if a Black Hole in the middle of nowhere had no food, the reason this is reported is because the Black Hole is apparently sitting in the middle of food, but simply not eating it. Now the odds are that, yes, there's limited matter getting into the accretion disk, but what the scientists are wondering at the moment is 'why?'.
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I suppose it's possible that the black hole has eaten its accretion disc and there just isn't enough matter around to register now (or rather, now 11 million years ago).
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the cyclical nature of galactic black holes has been known for some time, afaict this is just the first time a phase change has been witnessed in action
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What The_E and Phantom said. That's a mystery without one. It's not as if the BH can suddenly stop sucking **** into itself.
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Exactly, and I quote myself :
it's not as if a Black Hole can actually do anything about its mass, and therefore its gravitational pull
There's still a vast amount of confirmation, review and research before it becomes a mystery without one, however. There's no real point to saying 'Oh, we thought it might to this, so there's no point checking whether that is the case or whether there are other factors involved', that's kind of like saying a bike moves because the wheels go round, it's true, but that doesn't mean there might not be more involved that is worth investigating whilst we have the chance.
And that's kind of besides the fact I used the word 'interesting', not mysterious.
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Of course. You did question the "physics of the hole", and that kind of talk triggered the BS detector for me. Sorry.
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Accretion disks may be variable in luminosity over very short timescales, even hours. But it is not this decrease in luminosity itself that is interesting, but rather that it is occurring despite being in an apparently material rich environment (due to high star formation rate).
It is probably the physics of the surroundings, not the hole or accretion disk itself, that is relevant here. Perhaps (and it's just a guess) the environment is very non-uniform and so the accretion disk is not being fed continuously.
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This further confirms my statement that space is bloody awesome
Space. Want to go in space.
(http://i0.kym-cdn.com/photos/images/original/000/120/151/space_core_wallpaper_2_by_deathonabun-d3eta23.jpg)
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when ever it eats a **** tone of meter is compressed into an extremely small space. this produces a region of space with crazy energy densities, (there is probably a bunch of fusion happening making the situation even more energetic) and the energy near the event horizon is therefore absurdly high. the radiation and ejected mater from this region pushes matter that is further away even further away than it already was. until the mater near the event horizon gets eated, then the above situation stops, then the further away mater starts getting pulled in again.
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I'd still prefer to think that aliens did something to a white hole.
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when ever it eats a **** tone of meter is compressed into an extremely small space. this produces a region of space with crazy energy densities, (there is probably a bunch of fusion happening making the situation even more energetic) and the energy near the event horizon is therefore absurdly high. the radiation and ejected mater from this region pushes matter that is further away even further away than it already was. until the mater near the event horizon gets eated, then the above situation stops, then the further away mater starts getting pulled in again.
No. The radiation from around black holes is caused by frictional heating of material spiraling around in the accretion disk. The gravitational field is extremely strong and compact, and therefore the increase in orbital velocity by moving only slightly closer to the hole is enormous. This heats material to the point of thermal emission in UV and X-rays before it crosses the event horizon.
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I had assumed the heating was mostly due to simple compression, but that was hardly the important point of my speculation.
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Sorry, I should have been more clear with what I was quoting and replying to. Ultimately the heating comes from the conversion of gravitational potential energy, rather than any sort of adiabatic process. Fusion is also not significant in most accretion disks, though it can happen in some cases.
Your speculation of radiation pressure and/or matter outflow as a means of regulating accretion is good, and is strongly related to what is called the Eddington Limit (http://en.wikipedia.org/wiki/Eddington_Limit). A really cool small-scale example of this phenomenon may be seen with GRS 1915+105 (http://en.wikipedia.org/wiki/GRS_1915%2B105#Growth_regulation).
It is unclear if this explains what is going on presently with NGC 253.