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Dark Matter Grows Hair Around Stars and Planets (forbes.com)
StartsWithABang writes: Dark matter may make up 27% of the Universe's energy density, compared to just 5% of normal (atomic) matter, but in our Solar System, it's notoriously sparse. In particular, there's just a nanogram's worth per cubic kilometer, which makes the fact that we've never directly detected it seem inevitable. But recent work has demonstrated that Earth and all the planets leave a "wake" of dark matter where the density is enhanced by a billion times or more. Time to go put those dark matter detectors where they belong: in the path of these dark matter hairs.
if we were to position our detectors in the wake of one of these hairs – if dark matter behaves as we expect it to — the sensitivity of our dark matter detectors will improve by a factor of one billion, immediately.
No it wouldn't. The sensitivity of the detectors doesn't change at all.
When you walk into a bright room, it's not bright because your eyes have just magically got more sensitive to light.
systemd is Roko's Basilisk.
I read that as " a nanogram's worth per pubic kilometer"
0_o
that, coupled with the hair thing... wow, the human mind hey?
Please startswithabang, go away.
Does this have something to do with string theory?
So your theory is that our current list of known particles is complete. Why is that likely, given that we've discovered new particles quite often in the last 100 years?
Possibly, but it's going to be invisible to any of the light spectrum we work in, though I do wonder if would be something neat to have the ladies caress your invisible locks of dark matter hair (sounds better than hairy dark matter)..
He tried to kill me with a forklift!
Force of gravity falls away at inverse square. Stars in outer edges of galaxy rotate much too fast, given the visible matter. You forgot to include your explanation for this. While you're at it, explain the bullet cluster. Cheers.
I do not want your cheap brainburning drugs. They are useless for work. And I am a working man today.
Hey nitwit, the theory of dark matter is only there because of the facts. We call it dark matter because we don't know what it is, but we can see it's there.
Ockham's razor: The facts suggest that gravitational force without visible source is being exerted.
Since the only known source of gravity we know is matter, we assume that gravitational source comes from some invisible matter, but we don't currently have any solid proofs for this specific assertion (although neither do we have any to the contrary, nor alternate viable theories).
It may yet appear that it does not. It may be some form of existence different than matter or energy; some wrinkles of spacetime or some sourceless gravity clusters. Since we don't know anything like that, "dark matter" is a convenient shorthand to describe that effect.
It's a bit like both with Rutheford's atom model and with Planck's quantization of spectrum.
The first - assuming that atom structure is a kind of "dough" with electrons being "raisins" fit the knowledge of that time explaining the "solid" nature of solids. It was blatantly wrong, proven by later experiments that found tiny nuclei in huge empty space. It was still a convenient shorthand for a time, to describe several observed phenomena and fit some observations - and for lack of better alternatives, it was accepted until disproven.
The latter sounded so incredible at first, that it was used strictly as a *hack* to obtain results that fit the experimental data, with belief that the underlying mechanism is vastly different, but undiscovered as of yet - so the "hack" was again a shorthand used to explain given phenomena, out of convenience, because again, we didn't know any better way to explain the behavior of photon emissions, or the stability of atom - even though practically nobody believed it to be true, just a conveniently close approximation. And then, surprise-surprise, more and more experiments confirmed - that "hack" was actually how the reality worked, that was not a mistake but a very unlikely - though ultimately true - description of the nature of atom.
Whether Dark Matter is another Rutheford's Atom, or another Planck's Quantum distribution, is to be determined and it will either be confirmed or invalidated. Currently, as a shorthand explaining the observed phenomena, it's doing pretty well.
Ya, dark matter grows hair around Uranus kinda grabs a headline...
Remember, when the facts don't match your theory
Correct. The facts don't match the theory. Galaxies could not hang together the way they do if all they consist of is the things we've already observed in the laboratory unless we change the law of gravity [to something enormously more complex - c.f. epicycles] or postulate the existence of something that interacts gravitationally but doesn't interact with light.
too bad for the facts
I don't get this. Nobody is ignoring the facts. That's why we need to change things. Dark matter is the heliocentric solution. No dark matter is the epicyclic solution.
The [difference between facts and] theory is easily explained
Don't know about easily. There's been a lot of "dark matter" theories that have fallen due to one or more inconsistencies with known physics.
by an abundant (making up 96% of the universe),
Necessary otherwise we have to change the theory of gravity
invisible,
If by invisible you mean doesn't interact with EM radiation then yes, this is required by the facts.
undetectable
It's not undetectable. If it were undetectable then we wouldn't need it. It's very detectable - its gravity is what makes galaxies hang together. Its gravity is what allows gravitational lensing to happen where there isn't any (visible) matter to make it happen.
magic
Definitely not magic. It has to agree with all the laws of physics. Conservation of momemtum, conservation of energy, speed of light etc.
"dark matter"
it's called dark matter because it doesn't interact with the EM spectrum. It neither emits EM radiation nor absorbs it.
that is everywhere and affects everything.
Actually, I think this is one of the great unknowns. Whether it's large numbers of light particles or smaller numbers of massive particles. Its primary interaction with the known universe is through gravity which yes, does affect everything, everywhere, at the speed of light.
God said, "div D = rho, div B = 0, curl E = -@B/@t, curl H = J + @D/@t," and there was light.
Thing is, Aether was meant to be an "anchor" - a selected reference frame for movement of light. Meaning it to be directly, firmly bound to EM radiation, an essential concept related to electromagnetic waves.
Dark Matter is completely oblivious to Electromagnetic spectrum, specifically entirely ignores it.
It might be some kind of aether, some field that is a source of gravity, that is fixed in space and has its own specific frame of reference. But it's definitely not what was discussed as the Aether in times when Einstein disproved it. Different interactions, different properties, an entirely different cup of tea - bound to gravity but entirely decoupled from EM, which original Aether was all about.
no they aren't. they have observations that don't match the math calculations and they are trying to account for it. just like right before the theory of relativity. they thought there was and extra planet due to unexplained observations in the orbit of the planets that didn't match the math
Prézeau’s work is particularly stinging for me, because about a decade ago, as a graduate student, I was asked by my advisor to consider this problem, which I did. But in my analysis, I only considered the effect that the passing dark matter would have on the planet’s velocity, not of the density enhancement in the planet’s wake.
Ya man i know what you mean. I almost solved a quantum formula for gravity myself as my advisor asked me to solve a similar problem. But all i did was use formulas like mg(h2-h1)=E and assumed frictionless spherical cows.
Dark matter isn't a case of "fact vs. theory", but "fact vs. fact". We have multiple methods of determining the mass of galaxies and galaxy clusters. One method - counting all the light-emitting stuff - gives a certain number, and all other methods (rotation curves, gas kinematics, gravitational lensing, large-scale structure analysis, and more) give a much higher number. Two possible conclusions: 1) Our understanding of gravity is wrong, or 2) There is a new component of the universe that does not interact with light. Option 1) fails a lot of tests: if you try to make solutions for gravity for certain systems, it doesn't work for others. Option 2) has a solution called "dark matter", a new weakly-interacting massive particle that explains almost all the observations (it's not 100% perfect, but it does much better than the changing-gravity option).
At the same time that all this was happening in cosmology, our particle physics friends were developing extensions to the Standard Model. In many theories they predicted new kinds of particle: ones that just happened to have a lot of the right kind of properties that the cosmologists needed for dark matter. Voila.
Dark matter is the simplest, most parsimonious, most elegant known solution that fits the observational data.
Source: I'm an astrophysicist and I do a podcast, and one of my first episodes was on exactly this.
Saying that there exist some non-baryonic matter is a theory. So they have fact (observations) and they manipulate the theory (by adding dark matter, dark energy to barionic matter to the model) to match the fact. Exactly what you were asking for. But if you have an alternate model to offer, go ahead, I'm sure astrophysicists would like to hear from it.
Maybe it is. Suggest a better alternative though. We're sticking to this one as long as we don't have any better.
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Yes, it would - given a theory fully consistent with the observation without the "god-like" dark matter. Which we don't have.
So until either a workable alternate theory is developed, or we manage to disprove Dark Matter through other means (e.g. discovering it's not actually matter) it's there to stay.
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Well, bring up an alternative that explains everything PLUS what DM does, BUT BETTER. ***THAT*** is how you do science, not just go "Oh, pooh, it's wrong. Prove me incorrect!".
GRAVITY is a "magical invisible thing". MASS is a "magical invisible thing", if all you're going to do is call something "magical invisible thing", then what the fuck are you standing on this frigging planet for? FLY AWAY. Because magical invisible things can't prevent you doing it, can it.
Wrong. Galactic rotation curves do not match with what is predicted by Newton or Einstein. The outer stars are orbiting much too fast. You either explain it with hidden matter, or you explain it by modifying gravity. The the fact in this case is the anomalous rotation rates. I suggest you need to look again into what 'actual' scientists do, because what they don't do is ignore interesting observations.
I do not want your cheap brainburning drugs. They are useless for work. And I am a working man today.
Ah, so your argument is that because he doesn't have an adequate theory to replace yours, your flea bitten theory must prevail.
I don't know what the right theory is either, and neither do you. Attributing the extra gravity phenomenon to dark matter is nothing more than a variation on the G-d-of-the-Gaps. Got a problem with gravity, Dark Matter. You could give the alien guy Georgio with the electric hair a run for his money.
You have that backwards. They're modifying theory to match the facts. They've tried to ignore darkmatter for nearly 100 years, but they can't get rid of it. The more information we get, the more real it becomes. It has reached a point in science where the numbers are slapping us in the face, saying, "STOP IGNORING ME!"
So the Universe is made up of hairy balls... that explains a lot.
"If any question why we died, Tell them because our fathers lied."
Look at the size of that boy's heed.
I'm not kidding, it's like an orange on a toothpick!
Well, that's a huge noggin. That's a virtual planetoid.
Has it's own weather system!
"What the American public doesn't know is what makes them the American public." -Ray Zalinsky (Tommy Boy)
They're not manipulating anything. They are observing that there are numerous objects which appear to have a lot more mass than is visible. Unless you think there is something wrong with our Classical view of gravity, then the obvious answer is that there is a lot more matter out there than we can directly observe.
Fucking hell, there's nothing worse than some self-appointed anonymous poster on the Internet who is some fucking arrogant and stupid that he thinks he understands something better than the scientists. And why is it that such arrogant fucktards always end up on /, trying to make themselves look oh so smart.
The world's burning. Moped Jesus spotted on I50. Details at 11.
>> why is it that such arrogant fucktards always end up on /,
I for one welcome our SlashComma overlords.
Attributing the extra gravity phenomenon to dark matter is nothing more than a variation on the G-d-of-the-Gaps. Got a problem with gravity, Dark Matter.
For more than two decades you could have written:
Got a problem with beta decay energy conservation, "neutrinos".
Even as invisible particles, they were the best explanation on the table to explain beta decay. Then they got detected as well.
So, in the chronology of the creation of the universe, we've officially hit the puberty epoch. Congratulations, universe! You are growing up so fast.
Those are some big hairy balls...
My eyes reflect the stars and a smile lights up my face.
"Remember, when the facts don't match your theory, too bad for the facts."
Our phlogiston-powered probe will find out how those dark matter hairs interact with the luminiferous aether through which our solar system is passing.
"which "original" Aether theory are you formally referencing?"
The one Michelsonâ"Morley experiment failed to detect.
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It strikes me somewhat as the discovery of the planets, including Neptune, and the theoretical, but ultimately nonexistent, planet Vulcan.
The planet Neptune was identified not by visual observation, but by mathematical calculation based on errors in the predicted orbit of Uranus. Something was causing changes in the orbit Uranus should have taken according to the Newtonian model, and what was missing was another planet. They then were able to predict where it would be, and later observations by telescope confirmed that.
Thus when Mercury's orbit could not be accurately matched to the Newtonian model, one of those same 19th century astronomers theorized that there must be another planet between Mercury and the Sun, which was dubbed "Vulcan," that would account for the missing aspects of the equation. It was only much later that Einstein's theory of relativity correctly and accurately accounted for the inconsistencies without any hypothetical planet between Mercury and the Sun.
All of this isn't to say that "Dark Matter" is wrong or inaccurate, more just to illustrate how things operate with a known scientific model. If you have a missing variable, it may mean that there's something else you're not seeing through other means involved, or it may mean your model is wrong. The way you test that though is to come up with, and test/observe for, those things.
unless we change the law of gravity [to something enormously more complex - c.f. epicycles]... No dark matter is the epicyclic solution.
I completely agree with your post. However, I really wish people would stop using the "epicycle" as something to denote ridiculous complexity.
The reduction of epicycles is NOT what drove the Scientific Revolution. Some facts:
- Medieval astronomers did NOT add "epicycles on epicycles." Owen Gingerich, one of the foremost historians of science and perhaps the world's greatest expert on Copernicus has spent nearly 50 years trying to stamp out this myth, which seems (according to him) to have originated with some ignorant writings in the early 1800s which had no clue how the earlier astronomical systems worked. If people actually understand how the system works and how the tables medieval astronomers used were constructed, everyone would easily comprehend why it wouldn't have been basically impossible (in a practical computational sense) for medieval astronomers to add "epicycles on epicycles," even if they wanted to.
- Even if medieval astronomers wanted to do this, they simply didn't make the required number of observations necessary to construct such a system. And even if they did the observations, their models of the sky weren't accurate enough to do the sorts of measurements necessary to see planetary position error. (The only way they could tell planetary position was in reference to the fixed stars, but those experienced precession over the centuries and Ptolemy's model of precession was screwed up and had inaccurate medieval corrections thrown in... that didn't exactly work well.) Bottom line: even if they wanted to measure planets with greater accuracy to construct such a system, they couldn't.
- The main reason why anyone got interested in these problems in the 1500s is because there were a few observations where Mars was REALLY out of whack (like 5-6 degrees) with the original Ptolemaic predictions. which happened at conjunctions. Copernicus was driven toward his system after one of these "Martian disasters." Tycho Brahe did observations of the same periodic problem in 1593, which probably led him to tell Kepler to work on the Mars problem.
- Copernicus did NOT eliminate epicycles. In fact, as he tried to make his system more accurate, he actually ended up introducing MORE epicycles than the standard Ptolemaic model.
- Kepler's greatest move toward greater accuracy was achieved by use of old Ptolemaic idea of equants to offset the earth's position around the sun correctly, which produced a MAJOR improvement in predictions, even still using the old epicycle model. The need for epicycles was finally abolished with Kepler's adoption of elliptical orbits, but this correction was much smaller, perhaps only about 1/10th of the improvement in accuracy compared to Kepler's previous advances still assuming the equant/deferent/epicycle models.
TL;DR: Epicycles were good "science" that more than adequately fit the data for ancient and medieval astronomers. Nobody was putting MORE epicycles in to make corrections to the old model, except arguably Copernicus himself. Nobody thought of replacing the old Ptolemaic model until people started doing enough observations to notice a real problem, and after that solutions were proposed almost immediately. And the improvement Kepler made by finally getting rid of epicycles was REALLY small (comparatively), especially seen in contrast to the corrections introduced by adopting heliocentrism and displacing the earth's orbit (both of which were still done in the old geometric system which required epicycles).
So, the modern practice of using "epicycles" as derogatory parlance for a bad, overly complex model doesn't make much sense.
But don't listen to me. You can listen to Owen Gingerich himself describe what he calls
Yours too, glad I read it.
He tried to kill me with a forklift!
Send some politicians and Comcast executives into the wake stream for a few decades and see what happens to them. Don't waste perfectly good chimps.
Table-ized A.I.
Wrong. Galactic rotation curves do not match with what is predicted by Newton or Einstein. The outer stars are orbiting much too fast. You either explain it with hidden matter, or you explain it by modifying gravity. The the fact in this case is the anomalous rotation rates. I suggest you need to look again into what 'actual' scientists do, because what they don't do is ignore interesting observations.
Or perhaps scientists don't have a clue how gravity works on a large scale.
Jesus was a compassionate social conservative who called individuals to sin no more.
What's your definition of large? I said it could be hidden matter that interacts gravitationally, or gravitational theories need to be modified. It appears that you've hung your hat on MOND. Personally, I'm just curious to see what the answer will turn out to be. Neither outcome will upset me.
I do not want your cheap brainburning drugs. They are useless for work. And I am a working man today.
gravity is as instantaneous as people can detect - ie its not at the speed of light.
That is not actually known. We still haven't figured out if gravity propagates at the speed of light or not.
Question: From TFA:
"Dark matter may make up 27% of the Universe's energy density, compared to just 5% of normal (atomic) matter, but in our Solar System, it's notoriously sparse. In particular, there's just a nanogram's worth per cubic kilometer."
So then, if it's 27% vs 5%, normal matter occupies roughly only about 0.185 of a nanogram per cubic kilometer? That seems on the low side.
Look back up at my post, now look back down, you're on the Internet. Now look back up. I'm a signature.
Too rapid galaxy rotation, too rapid galaxy cluster movements, too strong gravitational lensing, cosmic microwave background spatial spectrum. Alternative theories like Modified Newtonian Dynamics may explain one or two of these, but not all of them.
As an intrinsic property of vacuum energy. Most dark matter proposals still treat it as a special substance that varies in density around the universe.
I see that there remains an aversion here to questioning the cosmic plasma model. Rather than investigate the dark-mode filamentary plasmas we already observe crisscrossing the galaxy on numerous scales, theorists continue to play with their simulations -- and the public continues to buy into the notion that this is science. How many more decades will this go on?
First it talks about dark matter in the universe in general and then (after pointing out that "... in our Solar System, it's notoriously sparse") gives the low density value.
So you can't apply the percentages that apply to the universe in general to the solar system.
But no one says it doesn't exist locally. Quite the opposite, everyone thinks it does. It's just fucking hard to see.
It's not that cosmologists aren't willing to look at GR, and certainly are, but no potential quantum theory of gravity suggests an alternative to dark matter. And considering we all know there is physics beyond the Standard Model, and the potential for currently only hypothetical or even unpredicted particles, the idea that we should just toss out one of the most successful scientific theories in history because we're confronted with what looks like a lot of extra mass seems absurd.
But I get it. There is a certain type of person, underachievers mainly, whose only contribution to any discussion is to find the gaps in our knowledge and then proclaim researchers in those fields retards. It's pathetic, and contributes absolutely nothing.
The world's burning. Moped Jesus spotted on I50. Details at 11.
You know, if somebody registered that, they could make a slash without a beta.
Any comment mentioning moderation is automatically Offtopic.
Isn't it equally likely that the gravitational constant is not actually a constant, but varies across different regions of the universe? Dark matter is just a way of forcing equations to match reality, without acknowledging the equation might be wrong. It is the modern equivalent of aether.
Support microSD: in a post 9/11 world, it is unwise to carry your data on media that you cannot comfortably swallow.
I don't have to provide alternative explanation to point out that what I see here is an ungrounded assertion. They're trying to manipulate facts to match the theory, not the other way around like actual scientists do.
No actually you DO have to provide an explanation.
We observe things happening. We are trying to make an explanation why they are happening.
Your claim that "they are not happening" when all observations and evidence and facts show 100% of the time over a few trillions of observations that your claim is WRONG.
It's completely on your head to show why your already-proven-incorrect "thought" is not wrong.
The facts you claim are being manipulated are right there in front of your face with no manipulation by anyone - except yourself of course, who keeps insisting the facts must be ignored because they don't fit your personal crazy "theory"
So get to explaining
gravity is as instantaneous as people can detect - ie its not at the speed of light.
That is not actually known. We still haven't figured out if gravity propagates at the speed of light or not.
In 1916 Einstein figured out that gravity propagates at the speed of light. We just haven't measured it directly yet.
We don't see the world as it is, we see it as we are.
-- Anais Nin
The way it varies though - mapping out the "dark matter" - suggests interactions with common matter both ways. So it's not like "the underlying fabric varies" - it really behaves like matter, forming clouds, strands, that "hair" - it's not a generic field or a generalized property of space "resulting in galaxies".
MOND suggests some unknown as of yet function mu(a/a0). If that function was to fit the observational data, it would be incredibly complex; nothing as elegant and common as common [something]/r^2 or sqrt(v^2/c^2). It would be more like a function to describe shapes of clouds basing on air flow, temperature and humidity.
We don't know any other physical entity that would behave that way - move, flow, gather - than matter. And while still some predictions are defied and we can't say for sure it's matter, if we compare the effects to known behaviors of various physical entities - waves, fields, energies - this one has strong similarities to matter and very few to others.
For example, space expansion is uniform; about all of cosmos expands at the same, flat rate that slowly changes over time, but is independent of location. Its source is described as "dark energy" but you can have justified doubts if it's really energy because its interaction with reality seems really unidirectional: it affects space, but the space and its contents don't seem to affect it. In case of dark matter though, the similarities are striking.
And if you think about difficulties of detecting it - it doesn't interact with electromagnetism... What percentage of our observation methods are not based on electromagnetism? All known matter keeps its structure - solid, gas, structure of atoms - due to electromagnetic forces. Bindings between atoms are all about electrons and protons interacting electromagnetically. All of light is EM wave. Most of non-electromagnetic observations like neutrina or collisions of neutrons - boil down to interactions that *eventually* produce some EM influence; be it an emitted photon, a neutron decaying into a proton and an electron, and so on - we observe them indirectly. If Dark Matter doesn't interact electromagnetically, it could sit right in front of our noses and we'd be unable to spot it. A solid chunk of dark matter could directly phase through a solid chunk of steel, because there's a lot of room between electrons and the nuclei and no force (electromagnetic!) that would prevent particles of the dark matter occupying locations in between; it could even phase through the nuclei because who says it needs to follow Pauli's Exclusion Principle? It's enough that it interacts gravitationally, and so your chunk of steel would exhibit 30% higher gravitational pull - but since its original gravitational pull is piconewtons, the change would be undetectable.
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I kind of of thought of dark matter as, the matter of light that we cant measure at rest, but there is so much out there it adds up.
Stars send it out, but when it strikes celestial bodies such as earth it collects. But most of it it falls out as earth moves along it's orbit as it's low interactive to all things including gravity.
The spirit of resistance to government is so valuable on certain occasions that I wish it to be always kept alive
Dark Matter's effects have been measured with 9 sigmas of confidence, well beyond the requirement to show something is there. And we know of sure that "something" cannot be barionic. We have better measurements of Dark Matter than Relativity.
It's just a glitch in the program. It's a holographic universe, after all. Really, it's a holographic multiverse. We're just one of many!
Obviously, I'm not serious.
Or am I?
"So long and thanks for all the fish."
One of the smartest minds on the subject, as determined by the community of highly regarded physicists, of MOND did almost 10 years of math and came up for an answer for MOND. But it required an unknown non-baryonic matter. He reinvented Dark Matter. It also required that we ditch Relativity. As it stands, it seems that even MOND requires Dark Matter. It also seems that Relativity is now dependent on Dark Matter. Any theory that tries to get rid of Dark Matter also needs to reinvent Relativity. Good luck with that.
Do you actually understand what you're speaking about? Dark matter is not, absolutely, any one thing. Dark matter is a reference to something we're unable to view and can only speculate about. Dark matter exists, by default, because we can not see it and we can demonstrate and measure that we're not seeing something. What that something is, is open to speculation. However, dark matter absolutely does exist. We can't see it - that's WHY we call it dark matter. It's there. We can measure and tell it is there. We speculate as to what it is but only a few overeager journalists are making statements about this being definitive. Everyone else knows that it is speculation - except for you.
Do you even science? I'm not even a scientist (my degree is in mathematics) and even *I* know this. Well, I guess, for some definitions, I am a scientist but I don't think of myself as one. I've done very few lawful or not-sexually-related things while wearing a lab coat, for example. I'm certainly not an astrophysicist. But even *I* understand this. No, dark matter does - by very nature of what it means - exist. We know it exists. We have some working models that try to explain it but they're not completely working yet so I guess we could call them half-working models. These speculations are based on those models and we'll use those models until someone proposes something better to explain the unaccounted gravitational effects that we can not see but can measure the effects of.
Again, we call it DARK MATTER because it exists and we can measure it but we can not see it. Because we can not see it, it's called DARK MATTER. (I'm pretty sure of this, at any rate - the disclaimer about my not being an astrophysicist is completely and obviously true.)
I mean, yeah, there are competing models that include things like this all being a 2D model and we're living in a hologram and thus are holograms ourselves but we don't really take those guys very seriously because they're more akin to God-botherers than they are akin to scientists. If you've got a compelling theory to explain this and maybe some maths to back it up, I'm sure they'll be happy to read your paper. Given that you don't actually seem to know what dark matter is and why we call it that and how we know it's there then I'm not actually sure how well your paper will make it through the peer-review cycle.
Is it a full moon or something? :/ Meh... Maybe it is me who's missing something. That could be true but I'm pretty sure that Brian Cox explained this nicely. I think even Morgan Freeman's gabbed about it but he's just reading a script. The little Asian guy from the college in has spoken about it too.
"So long and thanks for all the fish."
We can't see atoms are there either. Your point?
This logical fallacy is repeated so frequently that I think it needs its own name. I think "appello propter indispositionem" (appeal to ineptness) or "appellare multiplicitate" (appeal to complexity) are both appropriate. It's too complicated, we can't possibly be right! It's too hard, there's no way that's possible!
"So long and thanks for all the fish."
Too factual? They have its effects measured to 9 sigmas. We may as well be arguing whether the gravity exists. We "know" it's there, we just don't know how.
I used "stop ignoring me" to grab attention and add some humor. It's not so much that it was being ignored, but that it was being questioned. 100 years of observations and geniuses, and not a single iota against it and a mountain of everything for it.
Ironcailly, it's been shown(for the most part, but not truly proven) that without Dark Matter, we need Aether, because MOND does not work without a reference frame.
If that was the case, then wouldn't DM show up as smeary instead of clumpy?
I wondered how long it would take somebody to say that. Nobody like a hairy anus.
Dark matter is just one of two reasonable hypotheses. At the moment, it's safe to say that it's probably the more likely of the two. Modified gravity struggles to explain the bullet cluster, for example, whereas cold dark matter provides a compelling explanation. This is ultimately a scientific question that will be settled by evidence and logic.
I do not want your cheap brainburning drugs. They are useless for work. And I am a working man today.
Once you measure gravity by the gravitational lensing, galactic rotations perfectly matches Einstein. We just can't limit ourselves to matter that interacts with light. It's not hidden in the sense that we can't detect it, only that we can't see it. But that logic applies to a lot of science.
Minor correction: "without a universal reference frame"
I am not a physicist, but why does it have to be mysterious "dark" matter that's causing the discrepancy in the bullet cluster? If it's non-luminous regular matter, we wouldn't be able to detect it either. For that matter, there might be entire classes of elementary particles that exist in those regions of space that don't exist in ours. Homogeneity of the universe is taken as canon by physicists. But this is the same logic as saying "Mercury is a planet like all other planets, and its orbit is being affected by something unknown, therefore Vulcan must exist".
Support microSD: in a post 9/11 world, it is unwise to carry your data on media that you cannot comfortably swallow.
I am not a physicist, but why does it have to be mysterious "dark" matter that's causing the discrepancy in the bullet cluster?
Show me where I said it has to be, and we'll go from there.
I do not want your cheap brainburning drugs. They are useless for work. And I am a working man today.
I believe we're in agreement. Lensing gives you a window into all the gravitating material and not just the baryonic matter.
I do not want your cheap brainburning drugs. They are useless for work. And I am a working man today.
Predicted by Einstein
Correct. The facts don't match the theory. Galaxies could not hang together the way they do if all they consist of is the things we've already observed in the laboratory unless we change the law of gravity [to something enormously more complex - c.f. epicycles] or postulate the existence of something that interacts gravitationally but doesn't interact with light.
Spacetime is a continuum. Yes? Speed changes the perspective of time. Mass changes the perspective of space. No modification of gravity needed and no dark matter needed.
Put simply, there is less space where there is less matter. If you can wrap your brain around time dilation, wrapping your brain around space dilation should be simple.
"Someone needs to talk to the tree of liberty about its ghoulish drinking problem." by ohnocitizen
Why is it that astrophysicists "believe" in time dilation but do not "believe" in space dilation? Time and space is a continuum. They are inseparable as concepts. Energy is composed of spacetime and mass. When creating mass out of energy, spacetime is also created. The amount of mass determines how much spacetime there is; and therefore how much energy was used to create it.
"Length" is not a hardcoded value just as time is not a hardcoded value. There is less "space" at the edge of a galaxy. A flat galaxy that is rotating only appears to be flat due to the interplay of time and space. It is not actually so... from the perspective that we live in.
"Someone needs to talk to the tree of liberty about its ghoulish drinking problem." by ohnocitizen
You said "Dark matter is just one of two reasonable hypotheses"
I pointed out that non-luminous regular matter is also a valid hypothesis, so you are incorrect that there are only two reasonable hypotheses.
My point being - you are creating a false dichotomy. You are picking two possibilities, and saying dark matter is the more likely of those particular two. That is faulty logic.
Support microSD: in a post 9/11 world, it is unwise to carry your data on media that you cannot comfortably swallow.
Can't tell if this is part of the sarcasm implied in the first sentence. Changing the question when the answer doesn't work pretty much is what science is.
http://undecidedgames.blogspot.com
Practically all visible light that we see is emitted by atoms. So the only thing that we really see is atoms (emitting EM radiation).
Magnetic force does not fall off at an inverse square like gravity does, and is far more powerful. Maybe they should be looking into that first instead of making up invisible matter and energy. Then if that doesn't work then look elsewhere, but we are dealing with a religious belief here, not real science. It may involve a lot of science, but there is still a theory that they refuse to give up on even though it has been disproven over and over again.
There is only one question in science, though it has many variations.
Why?
Or there are other forces to take into account.
Maybe you straight up don't have a clue what you're talking about. Personally I consider that much more likely. It's pretty weird for you to be quite so passionate about the non-existence of dark matter.
I do not want your cheap brainburning drugs. They are useless for work. And I am a working man today.
To me, it's pretty weird for you to be quite so passionate about the existence of dark matter.
I am simply saying that you should look at other possibilities instead of discount them without any investigation. Sadly this has been standard practice in science as far back as we have records of scientific pursuits. When people base their world-view on a theory they fight to protect that theory with religious fervor. It is just human nature. Since I know about this nature I try very hard to fight it within myself, so when I look into things like this I also look at what opposing groups are saying. This lead me to look into the electric universe theory people. While there are certainly a few in that group that are idiots and have no idea what they are talking about, the others do know what they are talking about. If you know much about electricity and magnetism, which I do, a great deal of what they talk about makes perfect sense. Also, they are not just some group of nut-jobs who preach one thing and keep repeating it over and over again for decades. They are actually doing research and refining their theories.