Slashdot Mirror
Black Holes May Promote Stellar Birth
Porfiry writes: "The unusually high rates of star births seen in some galaxies may be linked to voracious black holes at the center of those galaxies, according to a new analysis of astronomical data by researchers at Johns Hopkins University. The new results suggest that galaxies with rapid rates of star formation and galaxies with active black holes, long considered separate phenomena, are actually links in a single set of evolutionary processes that shape the development of galaxies."
As interesting as all of this speculation is, there still remains one unfortunate fact which people here seem to have missed - there is no proof that black holes exist! They are still entirely theoretical constructs, and whilst standard general relativity seems to demand their existance, other formulations of general relativity don't, and we can't even say what a unified theory will predict once they finally get from being airy speculation to a solid theory.
It is still a very real possibility that astronomers and astrophysics alike have simply seized on a theoretical result without any thought of whether it is valid and used it to justify all kinds of celestial phenomena which have nothing to do with black holes at all. There's no excuse for such slipshod science, and it's all too likely that future scientists will look back and laugh.
Wheeler has a lot to answer for with his glib coining of the phrase "black hole". Do you think people would be so ready to assume their existance if they had been called "dark stars" as they once were? This smacks more of faith than reason.
There has been a plethora of research into massive black holes and their relationships to their respective galaxies. Of course most of the work is theoretical, but it is incredibly interesting!
The work is lead by a group of physicists who call themselves "nukers", and a lot of information can be found here.
The main questions that they have been struggling to answer are:
1) What factors about a galaxy do the size and mass of the blackhole at its center dictate?
and 2) Is it neccessary for a galaxy to have a blackhole at its center?
It is this first question which ties directly in with the rate of star formation and such material. If you're interested at all in the subject, I highly suggest checking out the links I provided above. (Yes, I'm too lazy to cut and paste the links again...)
--- I've been up for way too long, so I apologize if at times I made no sense. Just follow the links.
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"Of course, that's just my opinion. I could be wrong." --Dennis Miller
Saying that black hole jets help trigger star formation is very different from suggesting that these two phenomena are linked in a single set of evolutionary processes.
For example; it is widely believed that most stars in galaxies are being formed in relatively short powerful bursts. These bursts are triggered by the hierarchical clustering of subgalactic components. In many of these 'merging' galaxies spectral analysis does not show the black hole fingerprint (strong forbidden lines). These lines are hardly attenuated by dust, so if you dont see them it is unlike that the galaxy hosts an active BH.
Actually, in the merging scenario, which is favoured by theoreticians and observers (as opposed to the unlikely single monolithical collapse), the hardest part is to cool down star formation! Read: we have a hard time understanding what processes actually inhibit SF, let alone promote it.
Altho this research sheds new light on how complex the live and birth of galaxies is and how we lack in detailed understanding of the physical processes and interactions, to claim on the basis of a study of 14 Seyfert galaxies that this amounts to a breakthrough in this field is tentative.
If you read these type of articles precisely, you must be sensitive to the words ['may', 'might','help','possibly','suggest'] and give credit to the researchers effort to be cautious.
It must be pointed out that that if you really want to find out what the relation between BH and SF is you need to go to the high redshift universe. The problem is that hi-z sources are just to damned faint to study spectroscopically (no... hubble is useless here).
We are all in the gutter, but some of us are looking at the stars
It'd serve many people well to have a little understanding of the physics of a black hole.
Here are a three of my favourites:
Virtual Trips to Black Holes and Neutron Stars Page
Jillian's Guide to Black holes
As interesting as all of this speculation is, there still remains one unfortunate fact which people here seem to have missed - there is no proof that black holes exist! They are still entirely theoretical constructs...
The history of science is one of constant theorizing. Usually, a theory falls out of favour when we try to extrapolate it too far, and we realize that it doesn't fit any more. This is exactly the status of black holes, and this kind of speculation is exactly the kind of extrapolation that can disprove the theory.
However, I feel that unless you have a better theory, or unless you can decisively show how our current theory is sorely lacking, you don't have much grounds to lambaste our current scientific understanding. If you do have such a contribution to make to this discussion, I'd welcome it (it would be much better than my own comment).
There's no excuse for such slipshod science, and it's all too likely that future scientists will look back and laugh.
The history of science is filled with all kinds of foolishness, and no doubt our age will be included in that fine tradition. However, it's completely unfair to "laugh" at our ancestors' understanding of the universe without taking into account the historical, social, religious, and technological context.
Accountability on the heads of the powerful.
Power in the hands of the accountable.
Washington, D.C. = Senator Strom Thurmon denounced the reckless attitude of various stellar objects, including what he termed "voracious black holes" for unusually high rates of star births seen in some galaxies.
"Clearly, the family values I so highly espouse are sadly lacking with these voracious black holes, and this is the reason these holes see such unusually high rates of star births.".
The prune-like Senator went on to extoll abstinence for the Black Holes and other stellar objects. He then left for a prolonged nap.
Pay no attention to the man behind the curtain with all your metadata.
They are called black holes because light cannot escape once it has fallen in (in lay terms. Light takes forever to fall in. Matter doesn't). Whatever the technicalities, once it has fallen past the horizon, nothing, not even light, is going to escape. Hence the blackness. Hence black hole.
We can observe them (i.e. SEE) them by (a) their actions on other massive objects, e.g. in binary star systems etc. where the other member appears to orbit nothing, and (b) by the radiation the matter in orbit AROUND (not WITHIN the horizon, i.e. the black bit, but orbiting outside it), because as matter falls in, it emits radiation - in the most efficient process known. Makes fusion look like a candle to the sun in comparison. This radiation is redshifted by the mass of the black hole. So it has a kind of halo (in X-ray frequencies, not visible light).
Also, the maths works, i.e. you can work out it's mass from it's effect on everything else e.g. gravitational lensing, then work out it's radius by looking at the radius of the 'halo', and these figures agree with those predicted by the Schwarzschild (non spinning) and Kerr (spinning) metrics of general relativity.
You people saying they don't exist, crikey, you'd think the earth was round or something! Read things, take it in, and don't act like Prince Charles (non UK residents - acted like a fool ranting about man/science recently, without knowing what he was talking about).
Any physicists reading this please bear in mind that I am trying to explain something complicated to people with no background in this subject...