from the your-basic-space-colour,-is-black dept.
Despite a lot of effort in the last 30 years, there is still no evidence of dark matter.
From wikipedia:
Dark matter cannot be seen directly with telescopes; evidently it neither emits nor absorbs light or other electromagnetic radiation at any significant level. It is otherwise hypothesized to simply be matter that is not reactant to light. Instead, the existence and properties of dark matter are inferred from its gravitational effects on visible matter, radiation, and the large-scale structure of the universe ... [and] is estimated to constitute 84.5% of the total matter in the universe.
While the search was focused on exotic particles (with particle accelerators), researchers from Case Western Reserve University suggest that instead of WIMPS, weakly interacting massive particles, or axions, which are weakly interacting low-mass particles, dark matter may be made of not so exotic quarks and leptons. Forming lumps anywhere from a few grams to the size of a good asteroid, and probably as dense as a neutron star, or the nucleus of an atom.
Link to full paper [PDF].
(Score: 2, Interesting) by Anonymous Coward on Wednesday November 05 2014, @04:23AM
Drunk scientists continue to look for their lost keys around the lamp post.
(Score: 3, Insightful) by Bot on Wednesday November 05 2014, @03:08PM
oh ok then. It is 85% or whatsoever of all the stuff. It is transparent (does not interact with photons) else we would not even be seeing stars in the first place. I propose a name for it, aether.
Account abandoned.
(Score: 0) by Anonymous Coward on Wednesday November 05 2014, @04:02PM
I've actually said that dark matter/energy is the aether of our time.
Future society will look down on us with our naivety.
(Score: 1) by Istaera on Wednesday November 05 2014, @09:45PM
Dark energy is indeed matter which has gone missing. However, aether is not a particularly good name for it as it is often used as a way to refer to dark energy, a whole other story. The universe is currently expanding at an accelerated rate, but we don't know what could possibly be causing this, since shouldn't gravity cause the universe to collapse instead? The answer to this is something with negative pressure spread throughout the universe, i.e. dark energy aka aether.
I believe there's somebody out there watching us. Unfortunately, it's the government.
(Score: 0) by Anonymous Coward on Thursday November 06 2014, @09:45AM
Aether isn't a good name for dark energy either, since aether is something very specific: An assumed medium for the propagation of light. Neither dark matter nor dark energy is a medium for anything. If you want to make connections with concepts which were later found wrong, why not use phlogiston? [wikipedia.org]
(Score: 2) by Jeremiah Cornelius on Wednesday November 05 2014, @05:33PM
Nasruddin is outside his house, crawling around on his hands and knees on the sidewalk under a street lamp, intently looking for his missing key. His friend, Mansour, comes to visit him and sees Nasruddin on his hands and knees, crawling on the sidewalk under the street lamp, obviously searching for something, appearing frustrated.
Concerned for his friend, Mansour asks, "Nasruddin, what are you looking for? Did you lose something?"
"Yes, Mansour. I lost the key to my house, and I’m trying to find it, but I can’t."
"Let me help you," responds Mansour. Mansour joins his friend, kneels down on his hands and knees, and begins to crawl on the sidewalk under the street lamp, searching.
After a time, having looked everywhere on and around the sidewalk, neither Nasruddin nor Mansour can find the lost key. Puzzled, Mansour asks his friend to recall his steps when he last had the key, "Nasruddin, where did you lose the key? When did you last have it?"
"I lost the key in my house," Nasruddin responds.
"In your house?" repeats the astonished Mansour. "Then why are we looking for the key here, outside on the sidewalk under this street lamp?”
Without hesitation, Nasruddin explains, “Because there is more light here . . . !”
You're betting on the pantomime horse...
(Score: 2, Informative) by Ryan on Wednesday November 05 2014, @04:35AM
Physics graduate student here. Please allow me to explain the dark matter problem, in a nutshell, as it was explained to me in Astrophysics.
We know how gravity works. At least for big things far away. Newton got it, Kepler and others refined it, and Einstein perfected it. We've got gravity by the balls (on planetary scales, anyway).
When we get big telescopes that can see far away galaxies, we see something upsetting. A hockey puck shaped galaxy spinning about its center, but the edges aren't going as fast as Newtstein said! We think we know how fast stars in the galaxy should be going as a function of distance from the center, but SOMETHING is affecting the gravitational force to slow those stars down. Something we can't see. Literally, it just doesn't show up on our cameras.
That is literally the Dark Matter argument. We are so afraid of questioning Newton and Einstein (as we should be; dem guys was smart), that when we *see* matter behaving against their prescriptions, we conclude there is something lurking in the dark steering it.
^(Apologies if I got some of that wrong, it has been years since Astro.)
(Score: 0) by Anonymous Coward on Wednesday November 05 2014, @04:53AM
Pffft. Send a ship to investigate! What's the problem, can't get approval from the Federation Science Council?
(Score: 0) by Anonymous Coward on Thursday November 06 2014, @09:49AM
If Voyager showed anything, it's how long travels even inside our galaxy can take. Travelling to distant galaxies is out of reach even for Starfleet ships.
Unless you can find a wormhole leading to the destination, of course.
(Score: 3, Interesting) by mendax on Wednesday November 05 2014, @04:55AM
Claudius Ptolemy was smart, too, yet he was dead wrong regarding what went around what. His Earth-centered model of the solar system lasted a very long time. Having said that, it's true that Einstein was smart but he also didn't think much of quantum mechanics or the uncertainty principle ("God does not play dice"). While, I have a difficult time believing that the universe is truly random, that we simply have not yet discovered what drives this apparent randomness. Yet, if the universe is truly not random then the religious and philosophical concept of "predestination" would be true and I cannot accept that. I have free will, even if everything that is happening in my head that drives my choices is nothing but chemistry.
It's really quite a simple choice: Life, Death, or Los Angeles.
(Score: 1) by tftp on Wednesday November 05 2014, @06:52AM
I have free will, even if everything that is happening in my head that drives my choices is nothing but chemistry.
How would you prove this statement (that you have free will) ? It is obvious that all your decisions may be represented by a tree, but in the end you implement a specific path through that tree. How would one prove that this path is truly voluntary, and not preset in some punch card of galactic size?
(Score: 3, Informative) by sudo rm -rf on Wednesday November 05 2014, @08:40AM
rough translation (by me)
"I don't believe in freedom of will. Schopenhauer's statement 'Man can do what he wants, but he cannot want what he wants' accompanies me in all matters of life, and protects me from taking me and my fellow men as acting and reasoning individuals all too seriously and from loosing my good humor"
(Score: 2) by mendax on Wednesday November 05 2014, @09:10AM
How can I prove it? Well, like so many religious, spiritual, and philosophical ideas and concepts, they can't be empirically proven. Given that I am not an atheist or an agnostic tells you that there are just some things I'm going to believe in even if I can't prove them conclusively.
It's really quite a simple choice: Life, Death, or Los Angeles.
(Score: 2) by marcello_dl on Wednesday November 05 2014, @12:00PM
How do you prove that it being preset in some punchcard was not your choice? In other words how can you ascertain your freedom when "freedom" is a defined concept but "you" is not? For each definition of "you" a different and incomplete answer can be constructed. As for me, if i have the impression of being free i assume responsibility for it. If I err is on the side of caution, I do not like the"but I thought I were a puppet" epilogue.
(Score: 0) by Anonymous Coward on Thursday November 06 2014, @10:38AM
"Free will" doesn't mean that it wasn't determined (that would be randomness; you wouldn't call a random decision a free will decision, would you?). "Free will" means that it is, to a large part, determined by you. And while it is all too common to make a split between "you" and "your brain", that split simply does not work. Your brain is part of you, and therefore anything determined by your brain is determined by you.
Your brain cannot decide instead of you because your brain is you. If your brain decides something, they you decide it. And as long as the decision is essentially determined by your brain, it's a free-will decision.
(Score: 2) by stormwyrm on Wednesday November 05 2014, @08:23AM
Ptolemy's earth-centred picture of the universe might have been dead wrong, but it was not completely wrong [tufts.edu]. It was correct enough to agree sufficiently with the observations possible at the time, enough that people were reluctant to throw it away. Same too with Einstein's general relativity. If you like, you can think of dark matter as being akin to Ptolemy's deferents and epicycles, a patch on an erroneous theory to make it agree with observation. However, if you want to be the Copernicus to Einstein's Ptolemy, step up your game and come up with a theory of gravitation of your own, and make sure it explains things better where Einstein and his successors appear to have got things wrong, like on very large scales (dark matter and dark energy) and with very strong gravitational fields (black holes). This is exactly what Copernicus did to the Ptolemaic system.
Numquam ponenda est pluralitas sine necessitate.
(Score: 0) by Anonymous Coward on Thursday November 06 2014, @10:45AM
Actually Einstein did include a dark energy term, known as cosmological constant. After the reason he added it (to make the universe static) turned out to be wrong (the universe was found to expand), he threw it away and considered it his greatest mistake.
(Score: 2) by marcello_dl on Wednesday November 05 2014, @11:45AM
Do not mistake your POV for the one of a hypothetical God residing out of time. Put yourself in place of a god and think about a simulation.You know its outcome because you are outside time, whether it evolves randomly or mechanally. You cannot even rule out free will in mechanical world, because first you would have to define all the properties of the self which yoy cannot do from the inside. So please stop all those assertions masquerading as conclusions that atheism and religions do alike
(Score: 2) by marcello_dl on Wednesday November 05 2014, @11:48AM
Mechanally is my most poignant typo since the zx spectrum keyboard days...
(Score: 2) by mendax on Wednesday November 05 2014, @06:44PM
Oh, foo to you. I shall state what I believe as I please and you may do the same. I admit that what I believe is not always rational. Religion and spirituality cannot always be rational.
It's really quite a simple choice: Life, Death, or Los Angeles.
(Score: 3, Insightful) by Darth Turbogeek on Wednesday November 05 2014, @08:15AM
Dark Matter and Dark Energy are just another way at this point in time of "We have no fucking idea why the equations wont balance".
It's just another reminder humans actually know extremely little about what is going on in the Universe. Einstein didnt replace Newton, he added to it. Similarly there is clearly something else that will add to Einstein and Newton. And yet again, well find something else beyond that. Pretty cool frankly.
(Score: 2) by Geezer on Wednesday November 05 2014, @11:00AM
+5 Spot-on insightful. Dark stuff serves two practical purposes: first, it is a mathematical pons asinorum that sounds better than, "We are completely stumped." Second, it serves as a fabulous basis for research grants. Thus, if one accepts a Kantian or Hegelian epistemology, dark matter can be said to "exist" if only as an idea. James Jeans might have been right all along.
(Score: 2, Insightful) by terryk30 on Wednesday November 05 2014, @01:13PM
From careful observational work of astronomers (rotation curves of galaxies, and other phenomena I'm not familiar with off the top) we have the very strong suggestion there is nonluminous gravitating matter in galaxies, assuming that our very successful existing model of gravitation is correct. Assuming the latter (which is not irresponsible) astronomers do further, more careful work in order to determine (yes, if it exists) specific information about its distribution and properties. Not unreasonable ideas like brown dwarf stars are put forward, evaluated in regard to the above, and either posited or discarded as candidates - perhaps provisionally.
Meanwhile, theorists who explore possible avenues to new theories of gravitation look at the other possibility - using the observations made to constrain or inform their models. And in their extremely finicky work, particle physicists look for hypothesized or "surprise" particles with the requisite properties. And the cosmologists (also doing well-considered work) are in there too.
When I put it that way, it doesn't sound so contrived or trivial, does it? Just because the above workers have shortened "nonluminous gravitating matter" to "dark matter" for brevity doesn't mean it's no more than a notion.
A number of the above workers are going to eventually figure this out - funded by research grants (apportioned with consideration).
(Score: 1) by boristhespider on Wednesday November 05 2014, @05:09PM
Well, precisely. Sometimes I think people think that everyone working in astrophysics is an idiot who pissed away that 8 or 9 years of training it takes to even be able to begin thinking about contributing towards original research.
(Score: 2) by Gaaark on Wednesday November 05 2014, @12:55PM
And AGAIN, i point out the work of Julian Barbour who is working with Einstein's original Machian ideas of time and space being separate (because Mr. Barbour believes time is an illusion, and that it is emergent from movement THROUGH space).
He states that if you separate time and space, there is no need for dark matter or dark energy.
http://platonia.com/ [platonia.com]
--- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---
(Score: 3, Interesting) by Geezer on Wednesday November 05 2014, @02:04PM
I am not an astrophysicist, just a lowly EE with a nuclear reactor plant background. I can easily grasp the concept of separating time and space in terms of them being sui generis properties that together form the continuum. However, time must be more than an illusion or else we are faced with the paradox of instantaneous universes, are we not?
(Score: 2) by Gaaark on Thursday November 06 2014, @02:06PM
I am not an astrophysicist either, just interested.
According to Mr. Barbour, time is emergent from the movement of 'things' through space. If nothing moved, there would be no time (or, possibly? no need for time?).
We have created the need for time, and mark it with the passage of 'things' through space (the sun moving across the sky).
He uses 'best matching' to recreate the passage of time: say you take 3 particles in space. These 3 particles create the corners of a triangle. If the particles move, the triangle changes: 'time' is marked by the difference in the triangle... the particles have moved, therefore 'time' has changed. On his site, he explains better than i can how the 'illusion of time' goes.
I just found that the 'weird' things about Einstein's theories bugged the hell out of me: the twins paradox, time travel, etc. I don't believe that time travel is possible.
According to Barbour, if you separate space and time, time travel is not possible, and the arrow of time is explained: again, his site and youtube videos explain it better.
I just find his work fascinating and explains out the 'odd' things about Einsteins work.
--- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---
(Score: 0) by Anonymous Coward on Thursday November 06 2014, @02:22PM
And what is movement, according to Mr. Barbour?
(Score: 2) by Gaaark on Thursday November 06 2014, @02:37PM
The, uh, difference between the 'best matching' when comparing the points of the triangle?
--- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---
(Score: 0) by Anonymous Coward on Thursday November 06 2014, @05:01PM
(Score: 1) by PiMuNu on Wednesday November 05 2014, @09:04AM
> We are so afraid of questioning Newton and Einstein (as we should be; dem guys was smart), that when we *see* matter behaving against their prescriptions, we conclude there is something lurking in the dark
> steering it.
You have a model bias, in that you prefer a strictly reductionist model. This is your problem, not a physics problem.
There is no reason to suppose that a form of matter which only interacts gravitationally does not exist. We have observed:
- Matter which feels strong, em, weak, gravity
- Matter which feels em, weak, gravity
- Matter which feels weak, gravity
It is perfectly reasonable to posit a form of matter which only interacts via gravity. This would only be observable via large scale interactions. Nothing mysterious in there. It does not even go far against your strictly reductionist idealism.
It is fine to modify the Einstein and Newton gravity models and no one serious has a problem with this. But it is tough to find a self-consistent model that explains all observations without invoking Dark stuff. In the end, it probably requires some higher order terms or something which is going against your strictly reductionist ideal anyway, because you will introduce a new coefficient for the higher order term.
(My) jargon: strictly reductionist - each modification to a model reduces the number of free parameters in the theory.
(Score: 2) by FatPhil on Wednesday November 05 2014, @07:54PM
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 0) by Anonymous Coward on Thursday November 06 2014, @10:56AM
Because it feels no electromagnetic forces providing it with the necessary friction. As the planets demonstrate quite clearly, gravitation alone won't bring you to the center (well, that's not completely true because of gravitational waves, but the universe is simply not old enough that emission of gravitational waves could have made a measurable difference for anything at this scale, be it normal or dark matter).
Yes, there exist calculations for this. And those calculations also nicely reproduce the large-scale structure of matter distribution we observe in the universe. The same is not obtained with ordinary matter alone. Which is another argument for dark matter.
(Score: 0) by Anonymous Coward on Friday November 07 2014, @04:13PM
Actually, in slight contradiction to the other response (which otherwise I agree with), dark matter *does* cluster at the centre of galaxies. Actually it does so rather too strongly. It's known as the "cuspy core" problem -- that if you look at the density of dark matter predicted in a galaxy you get the density as you move towards the core increasing extremely rapidly. This can be alleviated by giving the dark matter some level of self-interaction. They can then actually repel each other as well as fall into each other's gravity wells, which flattens out the core somewhat. (Or you can play a few other games, or you can ditch a particulate dark matter entirely and swap to something entirely different, such as modifications to gravity or changes to how we're applying gravity.)
(Score: 3, Informative) by FatPhil on Wednesday November 05 2014, @01:06PM
> ^(Apologies if I got some of that wrong, it has been years since Astro.)
You need a bigger apology than just that - you have it completely upside down. The outer parts of galaxies are rotating too quickly. As if there was more mass further away from the galactic centre and the outer parts aren't really the outer parts after all, and the conclusion there must be halos of invisible mass outside the galaxy that we see.
Google "galaxy/galactic rotation curve".
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 0) by Anonymous Coward on Wednesday November 05 2014, @03:07PM
Not being a physics guy I thought what you stated was right but then someone said the opposite I could not refute it very well.
My understanding of the 'biggies'. We have a decent idea of that. But not how to 'make gravity' other than pile more stuff together. Like we know with matter and magnetism. Then things like magnetism why does it work? Why does it pull things together. We are not totally sure what creates these phenomena. We can describe them very well though.
HALOs and WIMPs are the most likely candidates for dark matter. But even then we are not sure. As we literally can not see the item in question. Like for example we still have not seen an extra solar planet. We have only seen the shadows. It is hard to tell in our 'neighborhood' as we have a giant flaming ball hoovering up all stray rocks in the area.
(Score: 1) by Ryan on Wednesday November 05 2014, @08:40PM
Ahh, thank you for that! For those interested:
https://www.e-education.psu.edu/astro801/files/astro801/image/Lesson%208/800px-GalacticRotation2_svg.png [psu.edu]
As you see, the outer stars are indeed observed to be faster than predicted.
(Score: 1) by boristhespider on Wednesday November 05 2014, @05:07PM
"We are so afraid of questioning Newton and Einstein"
This part at least is not even slightly true. Pretty much any day you look at the arxiv you find multiple papers working on modified theories of gravity. Almost, but not quite, all of them are metric-based like general relativity is (meaning that gravity is determined by geometry and not by any actual force) but that's because that fits the data far better than anything else. But even here you find repeated violations of even the equivalence principles, let alone the Einstein field equations that make up GR. Just off the top of my head, popular alternatives start with Brans-Dicke (which you can view as GR with a time- and space-dependent gravitational constant), move onto generalised Brans-Dickes and scalar-tensor gravities, take in so-called f(R) theories (in which the action of relativity, the Ricci scalar R, is replaced with a general function of the Ricci scalar; these can actually be expressed as particular Brans-Dicke theories, depending on whether you use the so-called Palatini approach in which affine connections, which correct for derivatives in a non-trivial geometry, are taken to be independent of the metric or not), move onto things like f(G) theories where G is the Gauss-Codazzi term which is the only combination quadratic in the Riemann tensor that provides a ghost-free action; it also takes in scalar-vector-tensor theories which not only add in a dynamical scalar a la Brans-Dicke but also adds in vector fields -- these models can often be expressed as theories of gravity containing *two* metrics, albeit very ugly ones; actual bimetric theories in which the existence of two metrics is postulated at the outset; or you can move away from geometry and take, to take a popular current example, Horava-Lifshitz gravity which is effectively an attempt to extend general relativity into the short-scale (ie quantum) limit using techniques from renormalisable group theory; and etc. and etc. Or you can do what I've spent time doing and look instead at how we're *applying* relativity on large scales; even if relativity is an accurate theory of gravity up to gigaparsec scales, that does not at all say that it's accurate to apply it as we do, taking on galactic scales a Newtonian approximation (effectively a mean field plus a tiny perturbation, if that) and taking on cosmological scales a quasi-Newtonian approximation (in which the mean field is stated explicitly but, vitally, is never proven to even exist and can in fact be proven to *not* quite exist). On both of these scales the approximation *may* be accurate, but we can't prove that and it may actually be woefully inaccurate.
Cosmology, and galactic dynamics, in some of these theories needs no dark matter. In others you need just as much as in the standard model. Typically you need at least some. In any event, the issue is much further from being settled in favour of particulate dark matter and particularly *a* particulate dark matter.
(Score: 0) by Anonymous Coward on Thursday November 06 2014, @10:30AM
Physicist here (but not astrophysicist).
No. We should not be afraid of questioning Newton and Einstein because they were so smart (if Einstein never had questioned Newton, we would have no General Relativity; and had a whole number of physicists including Planck, de Broglie, Bohr, Einstein, Schrödinger and Heisenberg not questioned Newton (indeed, Planck was the very first who did. even before Einstein), we would have no quantum mechanics.
More important, we should not be afraid of questioning anything, because questioning is essentially how science moves forward.
However questioning should never be confused with simply tossing out. Instead it means to explore many possibilities, and for each try to either find evidence or rule it out. And so far the dark matter hypothesis simply looks best. Moreover as it turns out, also particle physics beyond the standard model keeps predicting particles which fit the requirement for dark matter, for reasons completely unrelated to gravitation.
Of course that doesn't mean that dark matter must be the correct explanation. But it would be an extremely bad idea to simply dismiss it.
In addition, the much tounted alternative, MOND, is not at all satisfying. It essentially adds fudge factors to the existing theories (and it doesn't even do this to GR, but to Newtonian Gravitation; this means it cannot even correctly describe Mercury's movement). Mercury's movement could also have been explained by simply adding an 1/r^3 term to gravitation. The real theory, OTOH, looks very different from Newtonian gravitation. If the rotation curves should indeed follow from a different theory, I'd expect that theory as different from GR as GR is from Newton's gravitation. Maybe such a theory will emerge from quantum gravity.
Which brings me to another important point: General Relativity was not invented to explain Mercury's movement, and couldn't have derived from that. The purpose of GR was to solve the incompatibility of Special Relativity with Newtonian Gravitation. That it explained the movement or Mercury was a great proof of the theory, not its reason of existence.
To make an analogy: Both Uranus and Mercury showed deviations from the behaviour calculated using Newton's equations with the then known relevant gravitational sources (the sun and the planets up to Uranus). In both cases, an additional, yet unknown planet was postulated. That unknown planet is the equivalent of dark matter (a gravitational source we don't know yet).
In the case of Uranus, the prediction turned out to be right, and a new planet, now called Neptune, was found at the position where it had been calculated to be. So here the hypothesis turned out to be true.
In the case of Mercury, the prediction turned out to be wrong, and the deviation was ultimately explained by General Relativity as deviations from Newton's theory of gravitation.
Had Newton's theory of gravitation been dismissed as soon as Uranus was found not to behave exactly as predicted, we probably would not have found Neptune until much later. On the other hand, Mercury shows that sometimes the correct explanation indeed is a different theory.
(Score: 2, Interesting) by PiMuNu on Wednesday November 05 2014, @06:20AM
It's worth pointing out that the authors are proposing large atomic nuclei in the scale range of (grains of dust) to (asteroids).
So far no stable nucleus has been observed with sizes larger than a few 100 protons and nuclear physics models indicate that larger nuclei are unstable. So far no stable hadronic particles (i.e. made of quarks) has been observed with more than 3 quarks. So this would be exotic and either "beyond QCD standard model" (extremely large particles made up of quarks) or "beyond nuclear standard model" (extremely large, stable atomic nuclei).
I don't know if anyone has done the study "what is the smallest thing like a neutron star that can be stable". In a neutron star, gravity acts to make a very large, stable atomic nucleus; the gravitational pull of the nucleons counteracts the natural tendency of nuclei to fall apart at large scales.
The summary also mentions large bound leptonic objects. It is hard to see how leptons could be bound into large objects as they act as a Fermi gas so Pauli Exclusion Principle stops them getting too close. Essentially leptons have a minimum "temperature" and this prevents them getting cold enough to have densities on the scale mentioned in TFA. Again, unless some "beyond electroweak standard model" stuff comes to the rescue.
Jargon: lepton - neutrinos, electrons, stuff like that; quark - subatomic particles that make up protons, neutrons, stuff like that. Google particle zoo.
(Score: 0) by Anonymous Coward on Wednesday November 05 2014, @07:44AM
How about lots of tiny blackholes floating around?
http://www.space.com/25691-dark-matter-black-hole-atoms.html [space.com]
More:
https://en.wikipedia.org/wiki/Micro_black_hole [wikipedia.org]
http://www.livescience.com/27811-creating-mini-black-holes.html [livescience.com]
http://www.ukweatherworld.co.uk/forum/index.php?/topic/50780-ball-lightning-is-it-a-mini-black-hole/ [ukweatherworld.co.uk]
But if a tiny blackhole is surrounded by very dense charged stuff - the whole thing could be affected by magnetic fields right?
(Score: 1) by PiMuNu on Wednesday November 05 2014, @09:09AM
Yes.
I guess also there is a parameter space between micro black hole and neutron star where the quarks are bound by strong force but not so tightly that they collapse to a black hole. I don't know QCD so well so I don't know if there is a limit on when nucleons collapse under gravity. It is presumably not accessible experimentally and so model dependent.
(Score: 3, Insightful) by zocalo on Wednesday November 05 2014, @11:22AM
UNIX? They're not even circumcised! Savages!
(Score: 1) by PiMuNu on Wednesday November 05 2014, @11:44AM
Fair point.
I think that the first step is to attempt to determine what the mass range is for stable neutron stars. Someone else pointed out that micro black holes exist, so perhaps there can be micro neutron stars at all mass ranges?
(Score: 2) by martyb on Wednesday November 05 2014, @12:26PM
Excellent observation! From Wikipedia's entry on neutron star [wikipedia.org]s:
Separately (from TFA) The researchers were able to come up with some restrictions on the mass of these dark matter "particles":
Wit is intellect, dancing.
(Score: 1) by PiMuNu on Wednesday November 05 2014, @12:47PM
I believe that the Chandrasekhar limit arises due to the formation mechanism of neutron stars. If a star has mass Chandrasekhar limit, gravitational force is insufficient to overcome Pauli Exclusion Principle/Electromagnetic forces and so we get a white dwarf.
I think in this case one should imagine a different formation mechanism, for example neutron star collisions resulting in neutron star fragmentation.