dark matter origins Part 1

[jjohnson]

I think a cubic parsec (3.26 ^3) is about 34.6 cu LY. Hope that was a typo and doesn't affect subsequent statements.
J

[atherophage]

With all this dark matter floating about, would it not too coalesce into clumps, like normal matter did, making what would be, I guess, dark planets? We have the great movie called Dark Star, I saw it, so it must be true, according to my calculations.
If dark matter makes a dark star and this dark star collapses onto itself, does it make a white hole, from which everything escapes? I'd imagine such an object would be really bright.

[nick c]

welcome atherophage,
Yes it would, but then again, it might not. Dark Matter can do whatever the theory needs it to do.
It is really amazing stuff! Well, I am sure that we would find it amazing if we could get some in the lab and perform some experiments. But, who needs that! We've got the math.
[The movie [url2=http://www.youtube.com/watch?v=luaRtGn2 ... re=related]Dark Star[/url2] was hilarious. But it had nothing to do with Dark Matter.
hmmm, I did not know it was a true story ]
If enough Dark Matter were to collapse on to itself it would not make a white hole, it would make a Dark Black Hole or Black Dark Hole, but what does it matter? Since theoreticians (who got a pretty nice paycheck for their work) have already conjured up an object called a [url2=http://www.absoluteastronomy.com/topics/White_hole]White Hole[/url2].


nick c

[jjohnson]

By the way, Stefan's article sent me forth to read up on the references, further illuminating his points. Despite my tiny remark on a math point, it was an intriguing and educational article for me.

-And just in time to read through Science Fiction American's most recent claptrap article in their Oct 09 issue, "Black Stars, Not Holes". Almost makes you wish for the white hole theory, I mean, "rough concept proved by elegant math". They started out with a pertinent statement: "Black holes have been part of our popular culture for decades now, most recently playing a central role in the plot of this year's Star Trek movie." True enough! Popular culture is where they belong, and SF movies (a favorite form of mine) profit more from a suspension of reality and disbelief than, say, cosmology. After discussing what theoretical physicists think black holes are, Barcelo et al ask, "So much for fiction and theory. What about reality?" Then they go on and develop their idea that black holes probably don't exist because the [mathematical] singularity that exists at their core suggests that the theory fails at that point. Instead, and I swear I'm not making this up, as Dave Berry would always say in describing other human foibles and ideosyncracies, there are lots of dark objects ranging in diameter from several kilometers to millions of kilometers, "as best astrophysicists can determine", and which are prevented from collapsing and "taking the final plunge into infinite density" into the dreaded singularity by "...a sturdy construction material: space itself..." due to, and here is where you really want to smack yourself upside the head and say, "Now why didn't I think of that?!", a quantum effect called vacuum polarization, which resists gravity. The resulting collapsed-but-not-quite-all-the-way body is their Black Star. They would be extremely dim because light emitted from their surface [source of which is not explained] is extremely red-shifted by the intensely curved space-time near the Black Star.

Okay, there are millions of these contraptions emitting light under conditions in which nuclei presumably are so compacted that they can't engage in fusion reactions, only it's light whose wavelength has been stretched out, as it climbs up through the gravity well, so what can be observed must be... like, radio waves or something? I haven't seen many pictures on the NRAO web site of these little radiators, with puzzled radio astronomers wondering what all these point sources are. And what about the deeply red-shifted x-rays and all that high frequency stuff - can't those get equally down-shifted into visible light? Isn't the whole EM spectrum treated fairly even-handedly under this theory? (I mean, "concept idea propped up by elegant math and the approach of quantum-corrected semi-classical gravity"). "Thus, experience tells us," they write, "that matter following the laws of quantum mechanics always seems to find new ways of delaying gravitational collapse."

What experience is that? The reality of mathematical experience?

See why science fiction is so entertaining? Anything goes, and we have a lot of really excellent authors!
These authors' question still reverberates, at the end of their story: "What about reality?"

[StevenJay]

These articles are beginning to read as though they were written by the Monty Python crew. . . or maybe the old [url2=http://www.youtube.com/watch?v=hZqEpUw6 ... re=related]Firesign Theater[/url2]?

Note: A 70s mentality and generous amounts of mind-altering substances are required.

[The Great Dog]

The Great Dog believes that we may all, indeed, be Bozos on this bus.

[jjohnson]

We ARE all Bozos on this bus, but some are better bozos than others. It's an equal opportunity bus. My theory, with no mathematical support, which kills it right there, is that perhaps the inventors of the Black Star concept are like their inventions, extremely dim, emitting a lot of heat but not much light.

[mharratsc]

LOL!!


Mike H.

[jjohnson]

I was thinking about this idea (it's not a theory yet) of dark matter. It has been postulated to exist because, among other things, astronomers do not observe sufficient visible mass in galaxies to account for their relatively flat (solid disk-like constant angular rotation) rates.
So we have a form of matter which does not interact with regular photons, at least in any visible way, but it must interact via gravity with real (i.e., visible) matter in order to "correct" the gravity-driven Standard Model to reflect the actual rotation rates. When I say actual I mean imputed because our observation time has not actually been long enough to create a parallax great enough to see which way and how fast galaxies rotate, although doppler shifts are likely good enough to provide evidence if they are not mixed in or mixed up with intrinsic red shift. Left-right blue and red shifts are reasonable evidence that bears watching, of course.
The question was posed, "wouldn't dark matter form clumps?" I guess this could mean any size clumps, from dust to sandy grains to asteroids or even planetary sized clumps. Why not? I have read nothing in their descriptions of what they think is happening that prevents such coalescing, and if dark matter is an invisible analog of regular matter, it should exhibit the same gravitational behaviour, should it not, and clump up faster'n kitty litter in the rain?
And if it does, it should combine gravitationally with both its own dark matter cousins and with equal probability, its visible cousins in the gravitational neighborhood as well, isn't that right? Wouldn't every asteroid and star and gritty dusty plasma have gravitationally bound dark matter mixed right in there homogeneously with Our Stuff? Why isn't what we see twice as heavy as if the dark matter weren't in there? Do they share the same G constant?
If this gravitational mixing yields a distribution of dark matter in a galaxy which is essentially the same as real matter, then the galaxy should rotate according to regular ol' gravity mechanics and be re-e-a-a-l slow out at the tips, like Pluto. It's not, though, we think.
If the dark matter with its regular ol' gravity preferentially clumps up and creates a big invisible mass bulge in the inner quarter of a galaxy, what makes it do that? What new sophistry has been put forward to counteract dark matter's being pulled right out to the fingertips of the galactic arms just like real matter? None that I've read in the peer-reviewed comics.
Anyone who tries to explain that the Black Hole at a galactic center exerts a Dark Force on the Dark Matter that counters its gravity will be asked to retract his (her) post, because the Black Hole is there to suck everything in.
I think the Dark Matter advocates have a whole lot more 'splainin' to do!

Actually it is invisible forces that run the show, but they are just the everyday EM variety.

[mharratsc]

It's being confronted with logic like yours that makes the mainstreamists react so viciously to criticism. Jim.

They *know*, deep down in their little calculator hearts, that their 'dark-anything' means 'we can't explain it so we'll call it invisible and challenge you to prove us wrong mathematically! However, when someone like you comes along and says "Why doesn't it behave like normal matter then? Why no 'dark matter' planets, moons, mountains, stars, etc?" their only recourse is to spazz out and vindictively attack you ad hominem!

At least that is how it has appeared to me in most of the various debates I've seen between the "Mainstream" paid monkeys vs. 'anyone_with_a_different_idea_001'...

Mike H.

[jjohnson]

Actually I am not very confrontational at all; just curious. Not as curious as some of their theories, but really curious about them! Like our speed around the galaxy center - we can't just stick out a windmill or a hot-wire anemometer and read our speed on the Galactic Speedometer! I am sure that most of physics is really well thought out, and most physicists admit that a lot of their theories are just ideas and still open to grappling with alternate or better ideas. My gripe is that in a lot of basic physics there is much more interest in rushing toward unification - i.e. quantum mechanics with gravity - and little interest in a more basic unification - i.e., gravity working together with the other forces, all of which together conspire to call the reel we dance.
IMHO

The EU proponents are not trying to disparage the work done so far, and are not saying that gravity does not play a role. They are exposing those conceptual explanations for which they think that they can offer better, and different, and better behaved reasons. We all are viewing the universe from a long way away, even though we are in it for only a blink or two.

We have the advantage of creating plasma phenomena here on earth in labs (not tokomaks) and measuring it, learning the scaling laws, simulating it accurately, and relating the observations to the universe at large. We are not observing the universe and making up mathematical edifices that with continual tweaking to stave off aberrations and surprises about what we see. I think this is why engineers - especially electrical engineers - are on this float with us, and guide a lot of its progress. The universe is the real thing, the Big Time, and it takes a pragmatic viewpoint to create an applied set of ideas that work under the real conditions we encounter, whether here at the bottom of our safe little condensed matter gravity well, or out in the maelstrom of incomprehensibly large Birkeland currents closing in on each other across millions of parsecs of space to create a galaxy. That's our story.