Supermassive Diet: Black Holes Bulk-Up On Dark Matter 102
astroengine writes It has long been assumed that the size of a supermassive black hole in a galaxy's core is intimately related to the number of stars that galaxy contains — but it might not be that simple after all. According to new research, it may in fact be a galaxy's extensive dark matter halo that controls the evolution of the central supermassive black hole and not the total number of stars that galaxy contains. "There seems to be a mysterious link between the amount of dark matter a galaxy holds and the size of its central black hole, even though the two operate on vastly different scales," said lead author Akos Bogdan of the Harvard-Smithsonian Center for Astrophysics (CfA), Cambridge, Mass.
Might want to change your diet (Score:3, Funny)
After switching my diet, my blackhole no longer bulks up my dark matter.
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Bazinga.
Re:Dark matter only interacts gravitationally? (Score:4, Informative)
Dark matter might be amassed slower than ordinary matter though because it's not slowed down by the accretion disk and similar processes that get rid of momentum. IOW, a particle has to be headed directly into the event horizon, otherwise it'll miss and continue to orbit.
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Dark matter only interacts gravitationally? (Score:3)
So where are all the dark matter black holes?
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Re:Jump That Gun (Score:5, Insightful)
Re:Jump That Gun (Score:5, Insightful)
None of what you just wrote makes any sense... You're using word that a scientists might use, but out of their proper context. Again, google "galaxy rotation curve" and "bullet cluster". From what I gather, you seem to think we think dark matter exists because we're missing mass, but you are not taking into account the locations where we are missing mass. Black holes can't be responsible for what we're seeing. Also, dimensions are not places. Something can't be "in" a dimension. That's like saying that you got lost in a the third dimension... length! Dimensions are used to describe points in spacetime. The extra dimensions of string theory (which has yet to be proven in any way, might I add) can be thought of as extra numbers that you assign to every point of spacetime. That's all.
And just what a is a gravitational shadow?
Also the gravity that we see from black holes is from the core of the dead star that gave birth to them... Or in the case of supermassive black holes, the gas that presumably collapsed to form it. It is real matter, not twlight zone matter, and its effect is fully accounted for and routinely simulated.
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I'm not going to get into an argument about how many dimensions (in addition to the standard 3+1) the Universe has (do note that the inverse square law implies three spatial dimensions). However, saying something is "in" a dimension is stupid. You can say that most of the Universe is at one fifth-dimensional coordinate value and something else is at -20m from that (in a certain frame of reference), but that's not really saying it is in the fifth dimension, and I have no idea how you'd falsify it. If wha
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You're not hearing me. The "location" of that mass is obviously not in the center of the singularity, given the rotation rates. Of course there is no such thing as a center of a singularity, it has no volume at all, so I'm not sure why people would expect gravity, which depends on mass in a 4d manifold, to emanate from it.
(But dang, flamebait, really? It's a science discussion; it can't be flamebait. What are we supposed to talk about here then? We want hundreds of posts that all simply repeat the current t
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Last I looked, while that was a plausible theory, there was no real evidence for the Planck length being significant. It's a very plausible hypothesis, but at the moment that's all is.
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Honestly, it's hard for the lay-person to keep track, or really understand what this stuff is supposed to be.
It falls out of some math, but periodically someone says some of the assumptions might be a bit dodgy.
We can't see it, we can't measure it, we can't account for it .. but "magically" it accounts for specific ratios we take as accurate.
Many of us are just sitting on the sidelines wondering if it's a thing, or if it's a limitation in our understanding of the universe.
So, please, if you want to defend i
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The distinction here is the complete lack of humility showcased by people like you. You know that you know very little about the subject, and yet you start to make claims about how things work as if you had any authority. When you don't know much about something, you approach it with humility and try to better your reasoning before passing judgement. For example, I gave you some excellent starting points for your journey. How much time did you spend writing that post? Now, did you actually google "gala
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Dark matter is matter that does not interact using electromagnetism. Simple enough? Think something like slow, massive, neutrinos. (Three sentences.)
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Thank you for the correction. Dark matter is matter that does not interact electromagnetically, or does so only very weakly. Got it. Is there any reason to think it would or would not be affected by the weak force?
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Or this research should point us in the other direction. Perhaps it's the size of these black holes that is the source of the extra gravity that we currently attribute to the existence of dark matter...
I've always figured there is a term missing from our formula for gravity that is only significant at large scales. Perhaps with larger black holes, this theoretical missing term is similarly larger.
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First, thank you for phrasing your comment in a respectful way. It goes a long way to getting some good answers. I actually want to help you.
It is probably not supermassive black holes that are responsible for dark matter. That is in fact why I encouraged others to google for "galaxy rotation curves". Your orbital speed around the center of the galaxy is affected by the amount of mass inside that orbit and your distance from the point you're orbiting. Since most of the mass in the galaxy is close to th
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This seems to indicate there is extra, non-luminous mass out there
And that's the statement that I question. Sure there's an extra force, but is it due to more mass or just more gravity than we expect? Can a super-massive black hole contribute more gravitational force at greater distances than other forms of matter?
I don't have the data at my fingertips, and I suspect I'd get the maths wrong. But is this new finding inconsistent with my above poorly defined idea?
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As far as we know, gravity acts the same way for black holes as it does for everything else. There is no reason to believe that it could be different for supermassive black holes.
And this is the part that requires a bit of trust. People have tried alternate theories of gravity, but they always kind of single out one case and manage to do an ok job, but no one has come up with anything that explains such a large amount of observations as dark matter. Dark matter just works for a wide range of situations.
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We don't know what % of dark matter is simply brown/black dwarfs. Not a fucking clue. Assumptions are made. The only data we have is the number of brown dwarfs that are observable from earth compared to the radius we can observe them. That is not a statistically significant number (too few small brown dwarfs).
Re:Jump That Gun (Score:4, Informative)
Know is a tricky word, but there is plenty of evidence that most of the dark matter is not baryonic. The proportions of light elements formed at the end of the big bang gives a contstaint on the baryon density of the universe at the time, as do the ripples in the cosmic microwave background (which reveal the balance between radiation pressure and gravity in the early universe and tell us that most of the mass did not interact with photons at all). The bullet cluster is another piece of evidence. The stars in the colliding galaxies interacted with one another and with dust and merged into one bigger galaxy, but something, detectable by its gravitational lensing of galaxies beyond it, went straight through. It's hard to see how brown dwarves would have done that.
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As you point out BBN and CMB measurements do suggest that dark matter in non-baryonic. Another one to add to that list is structure formation, the large structures of the universe would be very different if the dark matter was baryonic.
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OK. I stand corrected.
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If we don't know how many brown dwarfs there are we don't know how much non Baryonic matter there is. Duh.
Baryonic matter has _not_ been excluded. It's unlikely to account for all of the missing matter, but certainly accounts for some.
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Yeah, as I expected ... a google of your precious fucking bullet cluster tells me it may or may not support the notion of dark matter.
But it isn't 100% cut and dry, and there are differing interpretations.
So if all you have is "yarg, teh bullet clusters" ... well, I'm afraid you're just acting like a child.
Use your big boy words, articulate something ... we're interested, but we're not taking you on face value because you act like a loudmouth ass.
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The only loudmouths are the people who are claiming to know better than scientists despite being completely ignorant of the facts. As I explained above, there's a difference between "I don't understand, can you explain?" and "I don't understand, this is stupid." The first will get you a helpful reply. The second will get you scorn, a keyword and an invitation to goole.
Also, I don't think you spent very long thinking about the bullet cluster. It is solid evidence for dark matter. Alternative explanatio
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So now we're assuming dark matter exists and we know how much of it is in any given galaxy?
I'm far from an expert in the subject but as I understand it's pretty simple. Total Mass (or whatever) or a galaxy - visible/known mass = assumed dark matter mass.
If we weren't assuming it wouldn't be dark.
Just Maybe (Score:1)
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Nice. Dark matter is the result of matter falling into the singularity.
One word... (Score:1)
Actually, it's an acronym but anyway...
MoND
Supermassive Diet (Score:2)
Don't assume what I assume (Score:1)
It has long been assumed that the size of a supermassive black hole in a galaxy's core is intimately related to the number of stars that galaxy contains
Not by me!
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Where's my latte dude? get back to work.
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Sorry, I didn't realize that English wasn't your first language. I take back my previous post. No bully okay?
Dark matter = Black hole excrement? (Score:4, Interesting)
Could it be that when energy/matter is ingested by a black hole it gets squeezed beyond the plank scale and into a dimension that is different than the space-time dimension we perceive; a dimension unconstrained by the black hole's gravity well -- effectively allowing the consumed energy/matter to exhaust back out into the galaxy as a different form?
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So you're saying there's possibly no such thing as a supermassive black hole, since mass falling into it gets spread out on a galactic scale in some mysterious way?
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I'm thinking more of a dimension (brane) that underpins the fabric of space; one whose shape can change independently of the presence of ordinary matter/gravity in our dimension. Only a black hole would be capable of exerting an effect.
This comment section makes my head hurt (Score:4, Insightful)
Why is it that people who have spent 30 seconds thinking about the problem think they know better than significantly more intelligent people who have spent decades? Especially when the (very large and convincing) amount of evidence for dark matter is easily accessible through a bit of googling. Guys, dark matter isn't just scientists throwing their arms in the air. It just works. Models with dark matter work much better than models without. And we've made multiple observations of things that point to dark matter existing. And no, it can't be black holes or brown dwarfs. That's been thought of a long time ago and it doesn't work. If you have a better idea and years of papers to support it, by all means, you can trash talk dark matter. Otherwise, please don't spread your ignorance. Science is not a democracy, and your opinion doesn't matter if it's unsupported.
Re:This comment section makes my head hurt (Score:4, Insightful)
And a lot of people here are adding brown dwarf stars to wherever needed so the gravity works. Same thing, except that we'd detect all those brown dwarfs.
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I'm arguing that assuming brown epicycles and assuming dark epicycles are the same sort of thing.
I do, in fact, believe that Uranus and Neptune are planets. They were discovered by people looking at gravity not working the way they thought, and hypothesizing extra planets. (Ironically, people hypothesized Vulcan in the same way, and Mercury's aberrations were because they didn't understand all the physics.)
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Because it's the new "phogiston" or the new "ether". It solves certain observational issues, but requires an enormous leap of mathematical and physical faith to assume that it has all the necessary characteristics.
Many of the models that "work better with dark matter" neglect the existence of matter that is not emitting light, but is nevertheless normal matter. Given the observational difficulties for objects and structures billions of light years away and billions of light years old, it's presumptive in th
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What do you have against neutrinos? (Neutrinos have a lot of the characteristics of dark matter.) Why don't you consider gravitational effects to be observational? Who cares about stuff billions of light years away when trying to explain the rotation of nearby galaxies?
Re:This comment section makes my head hurt (Score:4, Insightful)
It's not a big leap actually. Dark matter might even be neutrinos, although I'm not entirely up to date on that area of research. We just need a particle that interacts gravitationally and perhaps weakly with baryonic matter (that's the part that most people miss, a weak interaction is allowed). We already know stuff that does that. We just aren't sure there's enough of it, so we're searching for other particles that might fit the bill. Dark matter really doesn't have to be that exotic.
And I assure you that the observational evidence for dark matter is anything but subtle. Galaxy rotation curves are a quite spectacular way to show this effect at work, as I explained above. We also have the famous bullet cluster, a merger between clusters of galaxies where gravitational lensing shows a large amount of mass is found in the non-luminous parts. Another dramatic demonstration. Anyone telling you that the effects which justify the existence of dark matter are "subtle" is not being very thruthful. I mean, there's nothing subtle about galaxies smashing into each other...
So in short, dark matter doesn't have to be all that exotic and the evidence for it is quite easy to observe. So what's the big deal? Why do peole dislike it so much? people bring up the ether example, but they tend to forget about all the other particles we predicted and then later discovered...
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Self-selected readership who, at one point in their lives, were probably complimented and/or tormented for being intelligent, thus making it a component of their personality.
Preconceived notions which survive evidential disproving, making it easy to discard any summary based on the headline, or any article based on the summary.
Also, a rotating vocal minority who read a few words and immediately have to type their thoughts, because no one could possibly understand the topic more than them - as
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