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Earth Might Have Hairy Dark Matter
- anon6_ 11y agoI love theoretical physics - I do get tired of all the fluff articles churned out. It's like medical research. You'd think they've cured cancer by now. If you google around for dark matter, you'll find sources, including nasa.gov saying "direct proof" of dark matter has been found already. This was back in 2006. Theoretical physicists: disprove MOND, TeVeS, Mass in other dimensions, Scale relativity, or better yet, get better data before throwing around theoretical speculation with such confidence?
- qrendel 11y agoThese types of questions seem to come up a lot, and while I'm not an expert, here are some typical responses, from one of the last dark matter threads (in particular, the two top replies): https://news.ycombinator.com/item?id=10550732 https://news.ycombinator.com/item?id=10550732 I assume the tendency for the general public to give higher consideration to "other explanations," relative to professional physicists who seem to lean heavily towards the "matter" hypothesis, is lack of expertise in the current state of research. If you don't have a lot of good evidence one way or the other, all options seem about equally likely, so why take WIMPs more seriously than MOND or other hypotheses? Not that considering those alternatives is silly, but I think this might explain why this question keeps coming up even though the physics community seems pretty focused on the dark-matter-as-matter hypothesis. Though whatever the answer should turn out to be, it will certainly be an interesting development.
- deanCommie 11y agoThe edge of human understanding of the universe is a vague and scary place. When we dug deep below the atom level everything we took for granted fell apart. We had to invent an entirely new model of physics to make sense of our observations, which is complex and counter-intuitive (quantum mechanics) Would it be reasonable to assume that the same applies at the opposite end of the spectrum: from the sub-atomic to the super-galactical? Could the rules at such scales necessitate a new form of physics that we have yet to derive because of the difficulty of observation? I ask this because "dark matter" and "dark energy" always make me think of past primitive attempts to align unexpected data to existing models of understanding. Is it possible that they are just "echoes" or "shadows" of concepts that exceed the very nature of "matter" and "energy"?
- golergka 11y ago> Would it be reasonable to assume that the same applies at the opposite end of the spectrum: from the sub-atomic to the super-galactical? Isn't special relativity complex and counter-intuitive enough?
- fengwick3 11y agoI don't think special relativity is quite on the same level of strangeness (no pun intended) of quantum physics. For one, the axioms of special relativity are actually pretty believable, not to mention the incredible elegance of its integration with classical electromagnetism.
- wlievens 11y agoAnd the metaphors for relativity hold up longer than a few seconds once you start asking questions.
- jacquesm 11y agoIn a way relativity theory was such a new model, classical theory (Newton) worked well at all Earth scale observations of the time, it took quite few years after the theory was formulated before the first experimental evidence came in and relativistic effects are far more visible to us on a larger scale (but they're there on a smaller scale too, just harder to quantify). Who knows, there may be yet another theory that explains things on a larger scale even better than our current understanding. This may also increase or change our understanding of what happens at the smallest scales. Laws of physics trend towards unification, a single model to explain all scales at once.
- Florin_Andrei 11y agoThat's right. Things in this Universe are not scale-invariant. We are so enmeshed in the human-scale models, that anything beyond (above, below, far away from) this scale look alien. Growing up and bumping your head, as a toddler, into the kitchen table, you learn about a Universe that follows newtonian physics, euclidean geometry, and boolean logic. But then you look at vastly different scales and you learn that all these are human-scale approximations. The universe is post-newtonian and non-euclidean; and deep in the science of complexity boolean models are challenged by fuzzy logic. The newtonian/euclidean/boolean model we carry in our heads is just our little insular view of the universe.
- golergka 11y agoThis seems like something straight out of SciFi. Dark matter actually forming invisible rods that go through the Earth? Can we interact with these "hairs" if they are all around us? Can we at least detect it? It seems that all question I and any non-specialist can ask are stupid and irrelevant, but it's still so exciting to think of all the possibilities.
- hliyan 11y agoAs I understand, we can detect them through their gravitational effects and not much else. If we fully account for the pulls of all the non-dark bodies in the vicinity (Earth, Sun, Moon) and then manage to measure an anomalous gravitational pull (say on a mass connected to an extremely fine sensor) that changes with the motion of the measuring apparatus, that (I think) ought to do it. Disclaimer: not physicist.
- ccozan 11y agoactually, there is something that it is not really understood: the 5.9 years period of gravitational constant variation. [1]. Maybe the Earth is passing through such a filament? [1] http://phys.org/news/2015-04-gravitational-constant-vary.html http://phys.org/news/2015-04-gravitational-constant-vary.htm...
- hliyan 11y agoInteresting! But... it's been 15 years since my last university level physics course, but those error bars in the plot doesn't exactly lend lot of confidence to the idea of a periodic pattern?
- ISL 11y agoThere's been a follow-up paper from three scientists whose independent G-measurements reach some of the lowest-claimed uncertainties. http://arxiv.org/abs/1505.01774 http://arxiv.org/abs/1505.01774
- kamaal 11y agoNot a physicist either. But from what I understand from Lawrence Kraus's lecture 'A universe from nothing' is they found light bending(A phenomenon similar to gravitational lensing) around a massive start cluster, the amount observed and the mass in that area was insufficient to explain how that kind of phenomenon was possible. When looked at from the perspective of Gravitational lensing[A phenomenon that bends light] there is some kind of aether 2.0 with a mass that causes the gravitational lensing effect. Personally I think this is the wrong approach to work with this. We know that a cause c1, was the result of phenomenon p1. We are assuming another cause c2, which is very similar to c1 MUST also be happening due to p1. It might very well be there is a phenomenon p2 responsible for c2. We seem to be trying to state cause(dark matter) in terms of its side effect(phenomenon similar to gravitational lensing) without understanding what it actually is.
- k8tte 11y agoAll this "dark matter might be here and there" articles makes me feel they are missing the point. The article even fails to mention electromagnetism, which together with gravity causes matter to collapse on itself, causing black holes, which is the gravitational core of every galaxy. Electromaginetic fields has also been dictating the galaxy cluster structures (aka "mega structures" that has emerged since the hypothesed event we commonly refer to as the big bang). http://www.sciencechannel.com/tv-shows/how-the-universe-works/basically-electromagnetism-rules/ http://www.sciencechannel.com/tv-shows/how-the-universe-work... http://www.setterfield.org/Astronomy/Galaxy_Cores.html#electomagnetic http://www.setterfield.org/Astronomy/Galaxy_Cores.html#elect...
- danbruc 11y agoEssentially the defining property of dark matter is that it does not interact electromagnetically, so there is no point to consider it.
- k8tte 11y agoI think you misunderstood me. I am saying the electromagnetic force can be fit the bill where we currently are trying to squeeze in "dark matter". Please be aware that we have not discovered dark matter, we don't know what its made of, its properties, or really, if it even exists. But i get it. Thinking outside of the box is frowned upon around here. Lets all be fanboys, and fuck yea downvote me some more.
- danbruc 11y agoI never vote someone down, maybe three or so exception - can I look that up somewhere? That aside the page you linked to contains unscientific and plainly wrong nonsense and clearly shows no understanding of physics. I totally understand that you get downvoted for that content because it does almost the equivalent of saying that air doesn't exist because I can't see it. That being said, it must be stated first, and bluntly, that we don't think black holes exist. If not even light can get out, how is it the cores of galaxies are shooting out massive amounts of x-rays and material?
- musgravepeter 11y agoThe arxiv pre-print is http://arxiv.org/pdf/1507.07009.pdf http://arxiv.org/pdf/1507.07009.pdf
- Steuard 11y agoThanks! (I usually link to the arXiv abstract page rather than to the PDF: http://arxiv.org/abs/1507.07009 http://arxiv.org/abs/1507.07009 .)
- hliyan 11y agoI find this fascinating, but still purely hypothetical, yes? Basically: IF the observed expansion of the universe is indeed due to dark matter as we think of it, and IF such dark matter exist as streams, and IF such streams mix with ordinary galaxies, and IF the solar system is passing through such a stream THEN Earth MAY have dark matter filaments in its vicinity. IF we locate such a filament and send a probe, we might be able to learn about dark matter directly. Fingers crossed. That would be an amazing discovery.
- berntb 11y agoYou are mixing up dark matter and dark energy. The main effect of dark matter is not universal expansion, it is from both influences of gravity on galaxies and theory. See e.g. https://en.wikipedia.org/wiki/Dark_matter#Observational_evidence https://en.wikipedia.org/wiki/Dark_matter#Observational_evid...
- jon_smark 11y ago> IF the observed expansion of the universe is indeed due to dark matter as we think of it, and The accelerating expansion of the universe is thought to be caused by dark energy, not dark matter.
- poelzi 11y agoThe universe does not expand: www.cosmology.info/newsletter/2014.05.pdf I follow the BSM-SG model in which dark matter/dark energy is absolutely clear what it is and how it functions. The illustration is even a bit similar to the BSM-SG model, if you see it as the CL dimensions. Larger astronomical bodies have their own CL space, which means they carry a bubble with them those geometry is dependent on the body itself. This is why the photons get into a gravitational pull on heavy bodies, time goes differently, ...
- Steuard 11y agoThe Big Bang model of cosmological history is one of the most exquisitely tested ideas in science. Just for starters, any competing model would need to duplicate the highly sensitive predictions of Big Bang Nucleosynthesis (https://en.wikipedia.org/wiki/Big_Bang_nucleosynthesis https://en.wikipedia.org/wiki/Big_Bang_nucleosynthesis), the results of detailed simulations of structure formation (https://en.wikipedia.org/wiki/Structure_formation https://en.wikipedia.org/wiki/Structure_formation), and the existence of the cosmic microwave background (https://en.wikipedia.org/wiki/Cosmic_microwave_background https://en.wikipedia.org/wiki/Cosmic_microwave_background) (and at this point it would probably need to match the detailed spectrum of the CMB at least as well as inflationary models do). That's not an impossible task, but it's an awfully high bar: the widely accepted "Lambda-CDM" model (a specific Big Bang scenario involving both dark energy and cold dark matter) and its parameters have proven to be amazingly consistent under a whole bunch of very different observational tests. The odds that it has passed all of those tests so very consistently purely by dumb luck, while the universe actually follows some entirely incompatible set of rules and history, seem vanishingly small.
- CBABIES 11y agoDark matter seems like a misunderstood component of gravity. The current explanations just seem ridiculous.
- JonnieCache 11y agohttps://en.wikipedia.org/wiki/Modified_Newtonian_dynamics https://en.wikipedia.org/wiki/Modified_Newtonian_dynamics
- poelzi 11y agoI had some longer talk with a friend that is much more into logics about the MOND theory. The problem I have with this theory is, that I don't think that the MAX function used, is classical logic. Unfortunately, I have not found a real explanation, but we came to the standpoint, that you require some more complex logic to satisfy the MAX function and for physics, I stopped believing in anything beyond classical logic.
- cfontes 11y agoWell from what I know, gravity was once a misunderstood component of spacetime bending, so it would be proper.
- Ygg2 11y agoOne more interesting explanation I read in Hawking's Universe in a Nutshell, was that dark matter is extra gravity coming from parallel universes/extra dimension. Basically, what if gravity warps not just this plane, but other realities as well. It would explain why gravity is so weak compared to other forces.
- xioxox 11y agoModification of gravity has been found wanting. See e.g., the bullet cluster, https://en.wikipedia.org/wiki/Bullet_Cluster https://en.wikipedia.org/wiki/Bullet_Cluster
- idlewords 11y agoYou're not the first, second, or ten thousandth person to have this thought. But dark matter fits the phenomena better than any proposed modification of gravity. See the https://en.wikipedia.org/wiki/Bullet_Cluster https://en.wikipedia.org/wiki/Bullet_Cluster for a textbook example.
- pass-word 11y agoooooo
- jussij 11y agoThe good news is the idea has been put forward now. That means, through the wonders of experimental physics, sometime in the next 10, 20, 50 years we will find out if the idea sinks or swims. I wish the idea the best of luck, as we do need to figure out this issue once and for all.
- mizchief2 11y agoSo earth had dingle berries?
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- idlewords 11y agoOne thing I can't figure out from the arxiv preprint is the lifetime of these hairs, which I assume are a transient and dynamic phenomenon. Does anyone have an idea of how long a hair remains near the planet in question and retains its shape?
- danbruc 11y agoThey are present as long as there is dark matter flowing through the earth. In essence the gravity of the earth just changes the density pattern of the stream of dark matter particles the same way a lens focuses photons in the focal point [1]. So the interesting question is how persistent the stream of dark matter particles is. Also the earth is moving all the time around the sun and the centre of the galaxy and this alone should create a continuous stream because the earth moves through the dark matter background. So the even more interesting question is how dark matter is distributed - is there a more or less uniform distribution or is it patchy and the earth alternates between moving through essentially dark matter free regions and regions filled with dark matter. Unfortunately I have no answer for that. [1] https://en.wikipedia.org/wiki/Caustic_(optics) https://en.wikipedia.org/wiki/Caustic_(optics)
- geuis 11y agoFirst thing that occurred to me: could/would this look something like iron filings around a magnet if the dark matter stuff could be seen? Something like this. http://www.google.com/imgres?imgurl=https://apex-emovendollc.netdna-ssl.com/media/catalog/product/cache/1/image/800x800/9df78eab33525d08d6e5fb8d27136e95/d/-/d-16191-14.jpeg&imgrefurl=https://www.apexmagnets.com/iron-filings-12-ozs&h=800&w=800&tbnid=EswZ7wNlrPyluM:&docid=CyE5SHWaTnAIgM&hl=en-us&ei=Mu9VVoC3OsivogSZwaP4BA&tbm=isch&client=safari&ved=0ahUKEwiAmI2JjKzJAhXIl4gKHZngCE8QMwh3KFEwUQ http://www.google.com/imgres?imgurl=https://apex-emovendollc...
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- paki123 11y agoAt the risk of sounding like a total nutjob, every time I trip, feeling sensations of hair is one thing I always get reminded of.