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CERN Physicist Says Dark Matter May Be an Illusion
anonymousNR writes "A CERN physicist has a new theory explaining the rotational curves of galaxies. 'The key message of my paper is that dark matter may not exist and that phenomena attributed to dark matter may be explained by the gravitational polarization of the quantum vacuum,' Hajdukovic told PhysOrg.com. 'The future experiments and observations will reveal if my results are only (surprising) numerical coincidences or an embryo of a new scientific revolution.' Given the many theories around explaining various observations in recent times, there seems to be a breakthrough on its way in our understanding of the cosmos."
That's what I have been saying all along...
... finally someone bright! :-D
I totally believe you...
I hope so. Dark matter is the ugliest kludge to the standard model ever.
It's worse than the Plus upgrade for Windows 98.
Support FSF: Stop thinking with your wallet, and think with your imagination. (cc/non-commercial)
I've always felt something was a little iffy about dark matter/energy, kind of like how people used to thing space was filled with ether. Maybe this is a step in the right direction.
Just the title, without reading the article, is pretty hilarious i think; especially in the context of people arguing whether experimental particle physics beyond the standard model is worth funding. I mean, come on!
Yay for phlogiston and aether. Dark matter might end up on the list of ideas that physcists turned to in order to explain things that had other explanations. La plus ca change...
For all intensive purposes, "whom" is no longer a word. That begs the question, "who cares"?
I don't really understand much of anything you wrote, but if it was important to you to allow it to be subjected to Slashdot abuse then it must be worthy of at least some degree of attention.
It's amazing that saddos are still doing that in 2011, really.
Maybe I missed that course. What the heck is a quantum vacuum? Does it work better than a Kirby?
that the appearance and interpretation of an accelerating universe may be
an observed distortion
According to the article, if quantum dipoles are polarized, then tney produce an additional gravity field.
Does this mean that if this can happen artificially, we can control gravity?
It was quantum - he did it in Sept 97 and it showed here at the same time.
That's just what the Dark Matter wants us to think...
Dark matter is simply normal matter in adjacent (inaccessible to us) dimensions. The force of gravity is able to travel between our 3 dimensions and the additional ones, but matter and energy cannot.
Yes and no. Until we see it happening, we won't know if we can or not.
"None can love freedom heartily, but good men; the rest love not freedom, but license." --John Milton
He gives an example of a dielectric slab being inserted into a parallel plate capacitor, which results in a decrease in the electric field between the plates. The decrease is due to the fact that the electric charges of opposite sign attract each other. But if the electric charges of opposite sign were repulsive instead of attractive, then the electric field would increase. Back to the quantum vacuum scenario, since the gravitational charges of opposite sign are repulsive, the strength of the gravitational field increases.
If the gravitational charge of opposite signs are repulsive, it would mean that the "vacuum gravitational dipole" will have a tendency to separate into matter and antimatter.
As the antimatter is repulsed by the normal matter, wouldn't this require the introduction of another force (the "dark force"?) – that should be even stronger than the strong force – to explain how come we are not seeing flows of antimatter originating from the core of the galaxies?
Questions raise, answers kill. Raise questions to stay alive.
Dark matter might end up on the list of ideas that physcists turned to in order to explain things that had other explanations.
What really surprises me is, despite this, so many physicists have jumped on the bandwagon. Average Slashdotters have been more skeptical of they dark matter theory than physicists, from what I've seen.
"It's invisible, we have no idea what it looks like, we can't detect it, but it must be there because we have no other ideas." Exactly the same mistake as the theories you point out.
Does the scientific process require this, though - a decade or more of odd beliefs to spur the more rational scientists to actually figure it out? Do bad beliefs provide a framework for further study and building?
My God, it's Full of Source!
OUTSIDE_IP=$(dig +short my.ip @outsideip.net)
Here's a link to the actual PDF (arxiv version) and not the pay version
http://arxiv.org/ftp/arxiv/papers/1106/1106.0847.pdf
If matter and antimatter are gravitationally repulsive, then it would mean that the virtual particle-antiparticle pairs that exist for a limited time in the quantum vacuum are “gravitational dipoles.” That is, each pair forms a system in which the virtual particle has a positive gravitational charge, while the virtual antiparticle has a negative gravitational charge. In this scenario, the quantum vacuum contains many virtual gravitational dipoles, taking the form of a dipolar fluid.
“We can consider our universe as a union of two mutually interacting entities,” Hajdukovic said. “The first entity is our ‘normal’ matter (hence we do not assume the existence of dark matter and dark energy), immersed in the second entity, the quantum vacuum, considered as a sea of different kinds of virtual dipoles, including gravitational dipoles.”
He goes on to explain that the virtual gravitational dipoles in the quantum vacuum can be gravitationally polarized by the baryonic matter in nearby massive stars and galaxies. When the virtual dipoles align, they produce an additional gravitational field that can combine with the gravitational field produced by stars and galaxies. As such, the gravitationally polarized quantum vacuum could produce the same “speeding up” effect on the rotational curves of galaxies as either hypothetical dark matter or a modified law of gravity.
Basically what this means to me, is that the effect is on a super-massive scale and not easily manipulated by us without the technology to literally change things on super-massive scale.
That brings me to an interesting point, / . is just "the ramblings of socially-inept, technology-literate news-mongers".
Time is an illusion. Dark matter doubly so.
gonna work here anymore!!! amiright?
now, hows the war on terror going? how many muslims have we converted to christianity?
Oh, wait. Wrong meme. Sorry.
Just how much physics and cosmology has come to resemble STTNG technobabel ?
gonna hate.
What really surprises me is, despite this, so many physicists have jumped on the bandwagon.
This is because it is the simplest theory which fits available data. There are simpler theories, but they do not fit available data, and thus are of little value.
Average Slashdotters have been more skeptical of they dark matter theory than physicists, from what I've seen.
This is because average Slashdotters do not have even the beginnings of a clue about astrophysics, but think they are expert at every subject they ever heard mentioned on the internet.
If antimatter and matter are gravitational dipoles what about light? It isn't matter, yet it is bent toward matter. Then how does antimatter bend light? Does it attract light or repulse it? Normally the relativistic explanation for the bending of light curves follows from the explanation that matter causes space itself to curve. But I have trouble seeing how the same curvature of space could attract matter and repulse antimatter. Only fields can do that, not the geometry of space.
Then quantum phenomena must really get your panties in a twist.
I realize this isn't a group of physicists here, but most of the arguments people here are positing against dark matter more or less boil down to "it's unintuitive". Seriously, welcome to modern physics guys.
This new idea may be the start of something (and I must say this guy certainly doesn't lack in the self-esteem department), or it may fall apart as it fails to get further developed. But until it - or another alternative idea - gain some traction with the scientific community, it's a bit premature to start writing off dark matter. At the moment, it's the best solution we've got.
#DeleteChrome
From TFP: "Let us end by pointing that the rotational curves of galaxies are not the only phenomenon
which is currently explained by Dark Matter. For instance, CMB data are apparently in favor of
the presence of dark matter as a key for understanding of density fluctuations and the structure
formation in the Universe (see review of Einasto, 2010). While our Letter gives indices that the
gravitational vacuum polarization could be an alternative to dark matter in the explanation of the
galactic rotational curves, a tremendous work would be needed, to reveal if the other phenomena
could be alternatively explained by the vacuum polarization."
In other words, it's just another MOND theory, of which there have been many over the years. Wake me when MOND proponents write a theory that explains *all* the evidence for dark matter, CMB, nucleosynthesis, rotation curves, etc., not the particular phenomena they've cherry-picked. Until then, dark matter, whether that's WIMPs, MACHOs or axions, is the only explanation that fits all the evidence thusfar.
Have to post AC to avoid unmoderations, but I just wanted to point out that if a gravitational field can polarize particle anti-particle pairs, then an electric field can do it as well, because we know the spectrum of charged virtual particles. But his whole hypothesis relies on anti-matter having negative gravitational charge. That rewrites a whole lot more physics than dark matter does. In fact, I have trouble figuring out why the quantum vacuum doesn't produce real rather than virtual particles, since with negative gravitational charge the net energy of a real particle pair is nearly zero. But pointing out things like that to physicists is how I ended up an astronomer.
If there is no dark matter, then what is on the dark side of the moon?
Dark matter isn't undetectable, it's just difficult to detect because it doesn't interact with normal matter much. There's experiments, such as the cryonic dark matter search, underway attempting to detect it.
upon the advice of my lawyer, i have no sig at this time
So what's your idea? Given that the observed behaviour of the universe is inconsistent with what we expect, there are basically two possibilities:
1) Our understanding of gravity is wrong.
2) Our understanding of the matter in the universe is wrong.
Despite lots of effort, nobody has come up with a satisfactory theory of gravity which fixes the problem. And a new theory to fix the problem is not really more satisfactory in itself than a new type of matter - they both would be fudges to fit the data until some independent test came along. And it's not as if the scientists said "it must be dark matter, right, problem solved", there are active efforts to determine dark matter's characteristics and independently test for it.
There's been talk about phlogiston, but what about the neutrino? When the energy of electrons from beta decays didn't appear consistent with known laws of physics, someone (Pauli IIRC) said "there must be a new particle that we (so far) can't detect, which has properties X, Y and Z"... not unlike dark matter. And lo and behold, he was right.
Hajdukovic's assertion that the gravitational masses of particles and antiparticles are equal and opposite strains belief. Some theories suggest that these two quantities differ slightly in magnitude, but not in sign. See http://www.desy.de/user/projects/Physics/ParticleAndNuclear/antimatter_fall.html
"Electric Universe" theorist I take it? Or is it "Plasma Cosmology" now?
They've "jumped on the bandwagon" so to speak, because General Relativity explains everything else really fucking well, so we have a choice when we observe the anomalies; rewrite the entire rulebook, except we don't know how to, or postulate some form of matter that isn't *directly* observable (you know, sort of how like electrons aren't directly observable), and try to explain what it is. Maybe the latter is a fool's errand, but to throw out one of the most successful theories in history because the large-scale structure isn't quite what we expected would seem premature. At the moment, dark matter is the most parsimonious explanation for the data we have.
Anyways, this theory is even worse than dark matter, pulling matter-antimatter repulsion out of thin air to explain some of the observations that currently explained by dark matter, but pretty much being incapable of explaining other observations that are currently explained by dark matter. As another poster said, the idea that antimatter has an opposite gravitational polarity would suggest far more earth-shattering problems with modern physics than dark matter.
The world's burning. Moped Jesus spotted on I50. Details at 11.
existence is illusion.
I have trouble figuring out why the quantum vacuum doesn't produce real rather than virtual particles, since with negative gravitational charge the net energy of a real particle pair is nearly zero
I don't really get you here. As I understand it the quantum vacuum produces anti+normal particle pairs which annihilate more or less straight away. They are there and real but they add up to nothing. If quantum vacuum produced real particles that would mean a miss-match between normal and anti particles so matter would continually appear out of nothing (hey, are you Fred Hoyle?) but that violates conservation of mass energy.
http://michaelsmith.id.au
"Given the many theories around explaining various observations in recent times, there seems to be a breakthrough is on its way in our understanding of the cosmos."
So, it seems this quantum effect is able to affect the construction of a sentence is, fascinating.
My ism, it's full of beliefs.
This is because average Slashdotters do not have even the beginnings of a clue about astrophysics, but think they are expert at every subject they ever heard mentioned on the internet.
Why of course! You see, if it's mentioned on the internet, then the information is on the internet. And since it's on the internet, one can be an expert - everything is on the net. All it takes is to google, "expert knowledge on astrophysics", skim through and few articles, and BINGO! Slashdot expert and here comes my "+5 Informative"!
Where else can one be like Cliff Clavin on Cheers AND have the cites on one's fingertips!?
Except for the Mesopotamians. It's a little known fact that the wealthy individuals would have a slave with books and when one mentioned a fact and someone challenged them on it, the slave would look it up in the book - or scroll - and show it to the challenger.
And it's another little known fact that in the ancient city of Ur, there was a stone wall where the owner chiseled summaries of articles and folks would come by and chisel comments below it. The owner also gave certain people special chisels that left special marks for comments that were deemed more interesting, informative, or insightful and where able to chisel away comments that were posted to just piss people off.
"Dark matter" always seemed like nonsense to me, regardless of if this explains it or not!
You can't simply add more (magically non-light-interactive) mass to the universe to balance your equations, make up a name for it, and expect me to take that seriously!
The Internet has a capital "i"
Despite lots of effort, nobody has come up with a satisfactory theory of gravity which fixes the problem.
It's actually *ok* to say, "Our knowledge and theories are incomplete. Once we get more data we can fill in the gaps."
"I don't know, therefore Aliens" Wafflebox1
This is because it is the simplest theory which fits available data.
But it doesn't fit the data -- the dark matter theory is constantly being revised. First it's "90%" of the mass of the universe, then it's "70%", then we're back to "98%", then there's dark energy, then the fractions change again, and again, and again.
That's not a fit! It's not like we started at, say, 80%, then refined the fit to 82.5%, then an additional data helped us narrow it down to 82.515%, and so on. It's just jumping all over the place.
Secondly, it's not "fitting to the data", it's fitting to the difference between a theory and the data. There's a huge difference. And it's particularly galling that the "theory" used is Newtonian gravity, when it's been known to be wrong for a century! Several papers have been released that show that it's possible to make the need for dark matter vanish by using relativistic mechanics. Not exactly surprising that the "difference" is affected by the theory chosen!
Every research paper about dark matter reads something like "we use a simplified theory of gravity because of [excuse], and then oh look, we find that our hugely simplified model doesn't agree with observations, so clearly there's an invisible something out there". The excuses vary between: "The other paper did it too", "Relativistic equations are hard, and I'm lazy", "I don't understand relativity so I don't know how it could possibly apply to galaxy sized masses thousands of light years in size", and "my computer is too slow to do this properly".
This is because average Slashdotters do not have even the beginnings of a clue about astrophysics
Yeah, well, I studied Physics at a university level, and I think dark matter smacks of hubris, laziness, and weak logic. It sounds an awful lot like chasing the error terms in Epicycles a century too late.
The latest attempts to explain dark matter are an ever bigger joke, like Modified Newtonian dynamics. Here's a hint... we already have a "modified" theory for motion -- it's called relativistic dynamics!
Until some physicist demonstrates that dark matter is still required to explain measurements when the theory used is the full general relativistic model with speed of light delay included, I'm just going to automatically assume that dark matter is bullshit.
This kind of thinking is all too common in Physics. A classic example is the double-slit experiment. Every textbook states a formula for the spacing of the interference fringes that disregards a bunch of things, handwaving them away as "unimportant". A math-geek friend of mine in my physics class was upset by this lack of rigor, walked up to the whiteboard, and demonstrated that the simplifications can result in errors as large as ten percent or more in real-world scenarios!
Imagine someone basing a new theory of light based on the difference between observed interference fringe spacing and the simplified theory. That would be stupid, wouldn't it? Why is it then acceptable for gravity?
Its the perfect setup for a Star Wars joke.
EU = European Union you ignorant Americunt.
I'm not going to actually read the paper because i have a headache already, and i'm not saying that this guy isn't onto something, but if I had an 'automatic scientific paper generator', 'gravitational polarization of the quantum vacuum' is exactly the sort of phrase it would be likely to spit out :)
Dark matter has the same feel to it, but I am not a physicist. And some types of dark matter are observed aka neutrinos. If free neutrons didn't have such a short decay time, I'd consider that option as well. Without electrons the photon interaction with a neutron seems considerably hindered but again I'm not a physicist.
Disclaimer: I'm a lay person when it comes to things like quantum physics.
From my understanding of the arguments and analogies given in the article, the explanation is that vacuum does has a digravitational constant (the gravitational equivalent of the dielectric constant) greater than 1 in strong gravitational fields.
But, by the same quantum fluctuations getting polarized argument, shouldn't vacuum also have a dielectric constant greater than 1 in strong electrical fields?
Can't we test that last hypothesis pretty easily? Is it already known?
The crux of the article's hypothesis, that anti-matter has opposite-sign gravity, seems like an attractive idea and one that should also be easily testable once sufficient anti-matter can be manufactured and contained.
Put my fist through my alarm clock with its ding-dong death inside my ear. - The Blackjacks.
That's almost as good as the real kdawson's posts. But almost.
Huh. Funny. I must have skimmed past the "EU theory" line when I read that the first time. I read the first sentence and it seemed pretty obvious that the poster was a fan of so called "Plasma Cosmology". As it happens, I do live in the US, but I'm not actually a US citizen, I didn't grow up here. Anyway, perhaps I'm ignorant, but if you could enlighten me, I would appreciate it. What exactly is European Union theory? :)
Average Slashdotters have been more skeptical of they dark matter theory than physicists, from what I've seen.
To be fair to slashdotters - they're programmers.
And good coding is all about elegance & "parsinomy".
"Dark matter" offends the sensibility of any true programmer.
So you're saying the aether bunny isn't real?
Have gnu, will travel.
Average Slashdotters have been more skeptical of they dark matter theory than physicists, from what I've seen.
This is because average Slashdotters do not have even the beginnings of a clue about astrophysics, but think they are expert at every subject they ever heard mentioned on the internet.
I think its more because we have seen our share of bullshit.
This is because it is the simplest theory which fits available data
"The scientists are wrong, and there is a fault in their observation or methedology." THAT is the simplest solution to the available data*, and it is on the burden of the person proposing the magic intangible invisible particle to prove it is false, not the other way around.
We have, what, 100 years of good astronomical data? It took us longer than that to learn how weather works on this planet.
This is because average Slashdotters do not have even the beginnings of a clue about astrophysics, but think they are expert at every subject they ever heard mentioned on the internet.
Prove that astrophysics is right. I get the whole "spectrometer plus redshift plus observed luminosity leads to a fair distant measure" bit, but leaping from that to "I can measure the way galaxies rotate based on less than 100 years of data, even though they take way longer than that to do so" is something that fails the "my salary depends on me belieing this BS" meter.
Hell, has it even been fifty years since "Solid State" was the accepted astrophysical model?
Or even high school physics. Mention anything related to space like colonies and Space Elevators to see what I mean... The more mentally unstable of that crowd swerve into genuine mental illness quite readily.
The (now discredited) theory that America has a monopoly on morons.
Back in the 19th Century, we had two known planets with orbital oddities, Mercury and Uranus. Based on these oddities and Newtonian mechanics, the scientist Le Verrier predicted the existence of two other planets. When people looked, they found the one that explained Uranusâ"the planet Neptune, right where Le Verrier said it would be. So they went and they looked intently for the planet that would explain Mercury, the hypothetical planet Vulcan.
It wasn't until after 56 years of searching that Einstein finally provided a modified gravity theory that explained Mercury's orbit without the existence of Vulcan.
Unless and until the MOND family of theories produces an Einstein-level revolution in gravity theory, people will keep looking for the dark matter to make General Relativity work.
Anti-matter is simply gravitationally repulsive in all instances? This explains why we appear to be in a universe inhabited by matter: matter clumps, anti-matter disperses, hence, when we look at clumps of stuff, we find matter. (and anti-matter is 'dark' for the same reason) This might explain accelerating expansion of the universe (anti-matter continues to apply a repulsive force). And it seems to me that anti-matter pushing on the outside of a galaxy would have much the same effect as additional matter pulling in from the inside of a galaxy.
Admittedly, my qualifications to explore this scenario quantitatively are limited.
When things get complex, multiply by the complex conjugate.
This is because average Slashdotters do not have even the beginnings of a clue about astrophysics
So true.
Yeah, well, I studied Physics at a university level,
I studied astrophysics at a postgraduate level, if that has any relevance.
Until some physicist demonstrates that dark matter is still required to explain measurements when the theory used is the full general relativistic model with speed of light delay included, I'm just going to automatically assume that dark matter is bullshit
You really think that hasn't been done? This is not a subject that gets written about accurately in the newspapers (or on wikipedia). But general relativity is not exactly breaking news. It's the bread and butter of astrophysics, and very little astrophysics is done without reference to it. Including it in the calculations of rotation curves for galaxies and galaxy clusters makes very little difference, (certainly nowhere near enough to explain away the need for dark matter) which is why some models don't bother with it. This paper by Hajdukovic, or something like it, might turn out to be right. It's certainly worth looking at. But there's a simple reason why all astrophysicists take dark matter and dark energy seriously. It's because the evidence is compelling.
I hope so. Dark matter is the ugliest kludge to the standard model ever.
So you'd replace a simple hypothesis that there is a neutral, weakly interacting massive particle which is too heavy to have been produced in our accelerators with something which requires a negative gravitational charge? This breaks the equivalence principle of General Relativity because, using anti-matter I can now trivially distinguish between an acceleration and a gravitational field.
Its also worth pointing out that one of the most promising theories to explain Dark Matter, Supersymmetry, was actually introduced to fix the hierarchy problem in the Standard Model (caused by the Higgs mass being so far below the Planck scale). So, rather than be a kludge to the SM, Dark Matter is actually something which can be explained by theories designed to fix other issues with the SM so it is really rather beautiful. A further "coincidence" (if you will) is that Supersymmetry also causes the strong, weak and EM forces to converge in strength at a single point around 10^16 GeV energy (~1mJ) which does not happen in the Standard Model.
Of course all this does not in any way make Supersymmetry correct but to suggest Dark Matter is a 'kludge' suggests that you already know what it is and the that theory explaining it is ugly. As a physicist working on the ATLAS experiment, to my knowledge we have no idea as to the nature of Dark Matter yet. Besides even when we really do have ugly "kludges" they are often just initial attempts to describe something which is real but new: the Bohr model of the atom paved the way for Quantum Mechanics; Kepler's laws lead to Newtonian Mechanics and Gravity etc.
Go to a fundamentalist church group some time and tell me you really think they are more capable of understanding when they are wrong.
Would you want someone to base their opinion of Americans based on trip to a US insane asylum? If not then why would you think a visit to a fundamentalist church would be a good way to judge a religion as a whole? Both are only fractions of their respective societies and both are filled with people who have a tenuous grasp on reality. It is bad science to use a biased sample like that on which to base your judgements.
Your link says that the Aether concept is now understood to be a perfectly valid theory:
... Subsequent studies with large particle accelerators have now led us to understand that space is more like a piece of window glass than ideal Newtonian emptiness. It is filled with 'stuff' that is normally transparent but can be made visible by hitting it sufficiently hard to knock out a part. The modern concept of the vacuum of space, confirmed every day by experiment, is a relativistic ether. But we do not call it this because it is taboo.
HTH, HAND.
Learn the rules so you know how to break them properly.
www.teslabox.com
Thank you very much for you that you have good anything for us,thank you again
Window on science 2-1
Scientific Models
A scientific model is a mental conception of how something works. We all use models. For example, we might have a model in our minds of how a car works and use this model to make practical decisions about how to start the car on a cold morning. Our model doesn't have to be right to be useful. We may be totally wrong about how the engine works, but our model will probably be useful as long as we don't extend it too far. Of course, if we decide to rebuild our own carburetor, we might discover that our model is no longer adequate for our needs.
A scientific model need not be right, but it must be useful. That is, it must allow us to make useful predictions about how nature works. Scientists use models as mental crutches to help them think about nature. A chemist, for example, thinks of a molecule as little balls linked together with rods. Real molecules are much more complex than this model, but it is almost impossible to think about chemistry without using such a model to visualize molecular structure.
The astronomer's model of the celestial sphere is very helpful, and we can use it to think about the sun rising in the east and setting in the west. We can imagine the way the stars move across the sky, and we can predict the motion of the sky as a whole. Of course, the model is wrong, but as a mental aid to visualizing the motions in the sky, it is very useful within its limitations
Some scientific models can be systems of mathematical equations expressed in computer programs that mimic the behavior of complex processes-an exploding star, for example. Our imaginations are not capable of numerical precision; such models act as mathematical crutches to help us "imagine" complicated processes with numerical precision.
Scientific models can range from general aids to visualization to mathematical equations that mimic the behaviors of complex systems. In every case, the model helps us think about nature. It doesn't have to be true, but as long as we don't press a model beyond its limitations, it can be tremendously useful. In a sense, scientists are not so much searching for ultimate truths as they are trying to build better and better models of how nature works.
Seeds, Micheal. "Foundations of Astronomy". 4th ed. USA: Wadsworth Publishing Company, 1997. Page 15. Print.
You say "The principal of science is that you seek truth through observable, repeatable experiments." Perhaps your definition of truth is different than mine, but I don't believe the goal or product of science is "truth", but it is making "useful models". Truth is quite a loaded qualitative word. I think it is to broad for a discussion like this. It's just a poor word choice that leads to a muddled mess. You later say "Scientists never actually claim to 'know' the truth about anything completely". So, according to you, they are seeking something which they will never find. That seems like madness to me. Perhaps, it makes sense to you and others, but consider how it sounds. Talking about models instead avoids that.
You said that "Scientists never actually claim to 'know' the truth about anything completely" and later you say "religions claim to 'know' things and require absolutely no proof at all other than faith". Do you see how you have stereotyped both groups? Neither of those statements fair to either side.
Science and religion have this in common: they are both abstract ideas. Humans try to communicate these ideas to each other, but each individual's unique experiences and personality shapes how they interpret these ideas. Scientists and Religious people have this in common: they are all human. Because there are good and bad people, there
Sisko: What's happening out there?
Dax: Gravitational polarization of the quantum vacuum.
Sisko: Ahh, gravitational polarization of the quantum vacuum.
Dax: Do you know what that is?
Sisko: Just a guess here. Technobabble?
But we already have some data, so why not try to fill in the gaps right now ? The advantage is that even crazy ideas often tell you where to look for more data.
How can you possibly not know about the Bullet Cluster? That is pretty much blatant evidence that there appears to be something there which is both dark and massive. Wouldn't a theory of dark matter be appropriate when presented with such evidence? (and, by the way, structures like the Bullet Cluster were predicted by the theory of dark matter - people said "well if it doesn't interact electromagnetically, we should be able to see places where normal matter got pushed but dark matter didn't, like when two clusters collide" - so they set out to look for something like that, and lo and behold they found it!)
And that's not even going in to the other things that dark matter predicts and nothing else does, like the Cosmic Microwave Background.
Or you could just read Starts with a Bang, Ethan Siegel is a lot better at explaining this stuff than Slashdot is.
Awsome, Who cares about dark matter. NEGATIVE GRAVITY!!!! Imagine what you can do with that. No more rockets. Hello trips to the solar system.
You really think that hasn't been done?
There aren't that many papers that even begin to cover the reasoning behind the simplifications made. A meta-study done recently showed that even the few papers that did mention the simplifications often just hand-waved it away without rigorously proving that a simplification can be made at all.
If reality doesn't match a theory, and the theory chosen is known to be wrong, the very first step must be to redo everything with the more complex, more correct theory. Anything else is a huge waste of everyone's time.
Secondly, most people assume that dark matter theories say something like: "matter in a galaxy is spinning with some radial velocity distribution X, has Y mass with distribution Z, but requires +W mass to explain X."
In fact, it's more like: "we can barely tell what mass the galaxy is, we're guessing based on luminosity, and based on observed velocity distribution X, we can determine the mass distribution Z using a simulation, but the simulation doesn't work unless we tweak the hell out of it. Adding a bunch of mass +W helps, but it's still wonky." The only "known" is the velocity distribution. Everything else is a wild guess, and the curve fitting is done using a long-running simulation with huge amounts of non-linear feedback using the wrong equations. What could possibly go wrong?
About the changing numbers, I'd like to see citations.
Dark energy is a completely different concept than dark matter, completely independent of it, and used to explain completely different phenomena. The only thing dark matter and dark energy have in common is the adjective "dark".
Note that we already know particles which have exactly the properties needed for dark matter: neutrinos. They are not massive enough to explain the observations, but they are a proof that particles of that kind can exist. It is of course not a proof that they do exist, but it shows that the idea is not as stupid as you want to make us believe.
99% of all descriptions of the double slit experiment (and 100% of those in textbooks) are for explaining the properties of quantum mechanics, not for a quantitative description of an actual experiment. The unimportant parts are unimportant for understanding. It's like complaining that text books introducing free fall don't take into account air friction in their equations, despite the fact that air friction can even dominate a free fall.
The Tao of math: The numbers you can count are not the real numbers.
After 15 years of nearly daily visits to this site, I can tell you that a lot of that bullshit has been in the comments.
Pain is merely failure leaving the body
'gravitational polarization of the quantum vacuum' sounds like something out of a Doctor Who episode. I know it's not, but man, can't you just see Tom Baker spouting that at some point?
Dark Matter is not like the luminiferous aether.
The luminiferous aether is a substance that was invented to explain something that seemed missing from our theories (specifically, what it is that the speed of electromagnetic waves given by Maxwell's Equations is relative to). It made predictions, those predictions were tested, and so the idea was tossed out.
Dark Matter is a substance that was explained something that seemed missing from galaxies and clusters of galaxies (specifically, there wasn't enough mass there to explain why they held together given how fast things were moving). The idea of Dark Matter made predictions, those predictions were tested, and they *confirmed* Dark Matter.
There's nothing magic about Dark Matter. And the lines of evidence are more than just some equations that don't balance out.
More here: http://365daysofastronomy.org/2010/06/26/june-26th-dark-matter-not-like-the-luminiferous-ether/
This is because it is the simplest theory which fits available data.
But it doesn't fit the data
Well, I am a physicist (doing my PHD, although not in astrophysics), and I can tell you that it certainly looks like the simplest theory that fits the data. I highly recommend Ethan's blog, who explains this very well, particularly http://scienceblogs.com/startswithabang/2011/03/good_ideas_bad_ideas_mond_and.php and
http://scienceblogs.com/startswithabang/2009/09/dark_matter_part_i_how_much_ma.php. Notice, also, that theory predicts that the percentage of darks matter and energy changed during the history of our universe.
Of course, the theory is not complete, and there should be further experimental confirmation, but it looks pretty good for now.
This kind of thinking is all too common in Physics. A classic example is the double-slit experiment. Every textbook states a formula for the spacing of the interference fringes that disregards a bunch of things, handwaving them away as "unimportant". A math-geek friend of mine in my physics class was upset by this lack of rigor, walked up to the whiteboard, and demonstrated that the simplifications can result in errors as large as ten percent or more in real-world scenarios!
Imagine someone basing a new theory of light based on the difference between observed interference fringe spacing and the simplified theory. That would be stupid, wouldn't it? Why is it then acceptable for gravity?
Well, I work in optics, and I have no clue what you are talking about here... Is it because the usual derivation uses tan(alpha) ~ sin(alpha) ~ alpha? Or because it disregards the polarization of light? I can assure you that both of those approximations are very good "in most cases". But that doesn't mean you can't use the correct formulas, if needed. More likely, your teacher was oversimplifying the problem to get accross the most important concepts without his students being drowned by little details.
But much, much more importantly, physicists know that arriving to the simplest model that explains all your experimental data is very important, because it lets you understand what's going on, instead of just making blind calculations. I can assure you that this is not an easy skill to learn, specially for math-loving students who are irritated by approximations (I know this from first-hand experience!).
First it's "90%" of the mass of the universe, then it's "70%", then we're back to "98%", then there's dark energy, then the fractions change again, and again, and again.
This is not a correct characterization of the history of Dark Matter.
First of all, if you really studied Physics in university, then you ought to know something about uncertainties. If not, then, shame on the people who gave you your degree.
The history of dark matter includes observations on different scales that include different amounts of "missing mass". On some of those scales, we have accounted for some of the "missing mass" with different things-- e.g. some (smallish) fraction of the missing mass in galaxy clusters turned out to be in very hot intracluster plasma (which can be seen in X-rays) (and, even though it's a smallish fractoin, it's more mass than all the stars in the galaxies!). Something like 2/3 of the "missing mass" from cosmology-- which, incidentally, was always considered one of the weakest constraints on dark matter, since the uncertainties on the most basic parameters like the Hubble Constant were HUGE until the end of the 20th century -- turned out to be Dark Energy (which in fact might not be a thing, but a pointer to a flaw in our physics).
The numbers changed, yes. But uncertainties were huge to start with, so there's no surprise that the numbers changed. Trying to claim that the changing of the numbers indicates that the theory isn't making sense is a standard rhetorical technique that somebody who claims to know something about science should be ashamed to use.
Until some physicist demonstrates that dark matter is still required to explain measurements when the theory used is the full general relativistic model with speed of light delay included, I'm just going to automatically assume that dark matter is bullshit.
Go look up the Bullet Cluster.
The gravitational lensing values used in the calculations of where the mass is in that cluster come out of General Relativity.
I don't buy this; to finance a group to do the calculations "properly" would take... $3m, give them 3 years to do it. I would bet that any of the big uni's would have a group who could do it, but perhaps we could spend $6m and get it done twice to check?
On the other hand we could spend $1000'sM and do what we are doing with satellites and detectors to look for dark matter over a period of 20 years.
OK it's because of "vested interests"... well, the Chinese, or the Belgians or the South Africans could (would, gleefully) do those sums too (did you know, many people from South Africa and China went to MIT? more shockingly quite a few Belgians did too). Now, if they did their national academies would gain prestige, the investigators would win medals and fame.. So why has that not happened?
The maths here call bull on you.
--------------------------------------------- "In the end, we're all just water and old stars."
I don't know much philosophy, but I am a scientist, and I wonder whether you're aware that the limits to perception that you described above are very similar to the limits of the scientific method?
All scientific experimentation and measurement relies on probing one part of reality with another. Typically we set up some physical conditions (using one part of reality for which we have seemingly accurate theories), and then we introduce some test target (another part of reality which we are investigating), and then we take measurements using probing or monitoring equipment, ie. yet more parts of reality which hopefully we have calibrated. You'll notice the assumptions here --- we're hoping that the measuring equipment doesn't materially affect our observations, and we're also making the assumption that we know everything about the physics of our test environment and our probes.
Needless to say, the above assumptions are incorrect, if we want to be absolutely strict and truthful about it. We know this, but we have a get-out-of-jail-free card. From past experience we are reasonably confident that we are using our equipment in a safe operating area within which our knowingly flawed assumptions do not significantly affect the validity of our results. In other words, we know that perfection in examining reality eludes us, but we also know that we're not going so far as to produce nonsense. Most of the time anyway. :-)
There is another rather embarrassing little point of which people who aren't physicists sometime are not aware, which perhaps needs to be highlighted too. We can't actually touch any part of reality directly. The most we can do is to bring (say) a probe in close proximity to a target, and then a variety of forces come into play which produce forces of action and reaction between the parts which give us the sense that we're touching something, but of course we're not. This is true at all levels, from surface tension to molecular and atomic and subatomic forces. At no time can any of our probes actually touch or directly sense the reality of a target. We're just pushing fields of various sorts against each other, fields for which we have reasonably accurate behavioral theories but of which we'll never know the true reality.
So you see, it's not so far from what you describe as reality according to philosophy --- we can't actually touch or see the real thing, and we never will because we have no means of doing so. That's perfectly fine for science though, because the scientific method doesn't require us to touch reality, but only to observe her behavior. And for that, being distant from reality herself is not a problem. The scientist can achieve everything that is required under these conditions.
In contrast, the philosopher who understands science is not so lucky. It must worry some of them that we will never know the actual structure of reality, but only know how she behaves. Philosophers who seek The Absolute Truth can't be too happy. :-)
I thought it was technically still September 1993 anyway.
I looked up the Bullet Cluster you're always on about. From wikipedia:
"Critics of dark matter have cautioned that astronomers expect sizable quantities of non-luminous baryonic matter to reside in large galactic clusters, positing that the Bullet Cluster phenomenon can be explained without requiring non-baryonic dark matter.[13] However, this explanation requires that baryonic dark matter is of the same amount as the luminous baryonic matter in the Bullet Cluster. This means that ~6 times the visible galactic mass exists at the gravitational centroids, possibly in the galaxies as MACHOs, brown dwarves, or cold gas clouds."
The world you experience is only a close approximation of reality.
I have bought some products from www.shopvipzone.com some days ago, High quanlity,low price, worthy of you buying.
I misread that as "matter may be an illusion". Funny...
It's actually *ok* to say, "Our knowledge and theories are incomplete. Once we get more data we can fill in the gaps."
What's not okay is to just throw up your hands and say, "our theories are incomplete, so let's not even try to fill in the gaps". If you are to attempt to figure out what's really going on, rather than give up and become an astrologer instead, you need to start coming up with theories, then test them. Dark matter, alternate gravitational theories, etc. When your current theories don't fit the existing data, more data isn't going to help at all until you start coming up with alternate theories -- then the more data can choose between the alternatives. Existing data does NOT fit a universe with no dark matter and gravity working the way we think it does. So, we have theories of involving dark matter, and theories (like this one) of gravity doing funky-weirdness. And that's okay. We'll work it out eventually. What's not okay is insisting we don't even try to come up with new theories when the old ones clearly don't fit the data at all (as a universe with no dark matter currently doesn't).
"Convictions are more dangerous enemies of truth than lies."
Using negative gravity would blow off the Atmosphere from the planet, resulting in a slow loss of it. This is because it would affect everything, not just the launched vehicle. Moreover its effect dilutes with the square of the distance, just like gravity.
Better to use a space elevator:
http://science.slashdot.org/story/11/08/14/0114242/Space-Elevator-Conference-Prompts-Lofty-Questions
Hey don't blame me, IANAB
A couple of comments here.
Firstly, there is a common misconception that dark matter is a pure kludge, introduced to explain the apparently discrepancy between the observed stellar content of galaxies and their rotation curves. However, at this point there are several independent lines of evidence for dark matter.
-- Weak and strong lensing by galaxy clusters, which distorts the images of "background" galaxies, and is a function of the total mass of the lensing object.
-- The pattern of hot and cold spots in the microwave background (CMB) whose physics is dominated by the gravitational potential of the dark matter, some 380,000 years after the big bang, long before the first galaxies formed.
-- The velocities of galaxies in clusters, which would not be gravitationally bound in the absence of dark matter.
Any of these observations can be explained by "modifying' gravity. However, each of these observations apparently requires a different modification to standard gravity from the others (not that the article being discussed here only talks about galactic rotation curves), whereas all these observations are consistently explained by dark matter. Consequently, Occam's razor alone gives you a strong preference for dark matter over modified gravity. Moreover, the properties of the CMB in the presence of dark matter were computed before they were actually observed (look up "acoustic peaks" or "Doppler peaks"), so dark matter is indeed a theory that has made successful and non-trivial predictions.
My personal sniff test for any modified gravity theory for dark matter is whether it least acknowledges the above issues -- if it doesn't, it is not worth reading. And this one fails it, as do most others.
Also, this theory apparently "explains" the Pioneer anomaly -- but that "anomaly" now seems to be explained by not properly accounting for the anisotropic emission of heat from the spacecraft, which means that this theory actually makes predictions that are at odds with observations.
Finally, so far as I can see the author of this paper is only tenuously affiliated with CERN (likely as a visitor, rather than a staff member there) -- this doesn't alter the value of the content, but the original posting using this affiliation to establish the author's bona fides, so it is relevant to that extent.
Missing my modpoints right now. This deserves a point up.
Last I knew, red shift and blue shift happened because of the shift in the Visible light spectrum. One was it's moving away from us, the other because it's coming towards us.
I about shat myself when I read the article saying it's a measure of distance. But these whack jobs have degrees and are intellectuals. We have to believe everything they say.
- Dan.
~ People that think they are better than anyone else for any reason are the cause of all the strife in the world.
Maybe you do not know how science works...
Theories are never finished, final, or proved. There is always the probability that, with more data and better tools, a new theory can be formulated that improves the old one. That is how relativist mechanics replaced newtonian mechanics. And yes, they replaced them. You may still use newtonian mechanics because, for its use in Earth, the error in the results is fairly low (lower than the error in your measurements, at the very minimum) and they are simpler to work with.
So, people is working in refining a theory that seems the better to explain the observed results. Yes, it may happen that the best explanation is a completely different theory, but we still have not found it. Then, again, what is wrong with that?
About your last line, if the new theory of light explains results beter than the current one, there is nothing stupid about it. What would be really, really stupid would be opposing it without even checking if it works.
Why can't
> 1) Rotational curves of galaxies.
> 2) Gravitational lensing - it's too strong for the amount of baryonic matter present.
> 3) Bullet cluster.
> 4) Small galaxies - the smaller the galaxy the more dark-matter-dominated it is.
1,2, and 4 all seem to be about gravity working against inertia. So how about a particle/mass/force which on large scale reduces inertia. We can make it non-interacting in other ways just like Dark Matter.
Not sure how 3 would fit into that but I don't know what is going on in such collisions.
Crikey, when will those scientist bod just listen and think.
Late at night, a drunk was on his knees beneath a street-light, evidently looking for something. "What have you lost?" asks a passer-by. "My graduation watch," replied the drunk. "It fell off after I flung myself out of the ivory tower into the vague proximity of the real world."
The passer-by watches the futile search for a few minute then inquires, "so which building did you leap from?"
"A few institutions up the street," replied the drunk.
"Why are you looking for it here if you lost it there?"
"Because the funding is better."
"And because the sirens of publish or perish made it hard to hear where it landed?"
"Yeah, that too."
We already accept spectacularly dim and neutral matter, but then we declare that a physical quantity known within the profession as "kluge matter" is a hopeless kluge to the standard model, because you can't see it where the funding is good.
Good call, brought to you by the same people who originally named "junk DNA".
Let me explain big science: A) Anything you can't fund your department to study is dark or dirty; B) If it's costing you money you raised to study something else, it's a rubber boot on a fish hook.
How about:
3) Our observations/deductions about gravity and/or matter in the rest of the universe are wrong.
That must be another possibility?
Prove that astrophysics is right. I get the whole "spectrometer plus redshift plus observed luminosity leads to a fair distant measure" bit, but leaping from that to "I can measure the way galaxies rotate based on less than 100 years of data, even though they take way longer than that to do so" is something that fails the "my salary depends on me belieing this BS" meter.
We don't even need 100 years of data to measure galaxy rotation, because we don't do it by seeing the stars move in the galaxy in question. All you really need is a galaxy that is more or less edge-on and two measurements of the same spectral line, one to the left of the galactic core and one to the right. the difference in redshift between those two measurements gives us a very, very good idea of the rotation of the galaxy because said difference is determined by the average motion of the stars towards or away from us at that position in the galaxy.
While it's good to be skeptical about things, it's bad to not understand at least the basics of what you're skeptical about, especially if you intend to calling BS about it in a public forum...
So can we start saying something like "Don't subscribe to existence what polarity can explain" ?
I think people really created a crazy mysticism over these "dark" matters and energy. I agree with the article, but I do not agree that there is no dark matter. I just think the attributes associated with dark matter were something else, like gravitational polarization. Turn off the lights, is everything glowing? F$#@ing dark matter yo! Space is full of things that do not emit notable amounts of energy. Gas giants are supposedly floating everywhere, not just around stars. Giant asteroids are everywhere. Get a clue!
But in order to know what data to look for you need working hypotheses.
Which is fertile ground for a host of cognitive biases. "Confirmation" and "Experimenter's" leap instantly to mind, especially when the experiments take a decade or more and cost billions of Other People's Money.
"I don't know, therefore Aliens" Wafflebox1
Not if the measurements are done competently. The ether as a straightforward medium was disproven by experiment designed to measure the properties of the ether. Of course, that wouldn't have been possible without having some idea of what the ether should be.
What's your alternative then?
"He made a joke, and I have severe crippling autism! I'll moderate him Troll, that'll show him!"
Of course, that wouldn't have been possible without having some idea of what the ether should be.
What's your alternative then?
Just keep on staring out into space. Who knows how much more stuff we'll discover.
"I don't know, therefore Aliens" Wafflebox1
The secret is to bang the rocks together guys. Chris
No way Oppenheimer was wrong about dark matter...
I have no problem at all with Dark Matter. Anybody who tries to remember if an introverted friend was at a particular party can understand Dark Matter.
It's Dark *Energy* that really sounds like made-up mumbo jumbo to me!
The problem here is that this idea is only a modification of the way in which gravity falls off with distance. Our current observations completely eliminate that as a possible explanation for our observations of dark matter. Basically, we have observed some systems where the physics of the situation has separated dark matter from normal matter (because normal matter experiences friction, while dark matter does not), and found that the mass surrounds the dark matter, not the normal matter. This kind of observation simply cannot be explained by a simple modification of how gravity falls off with distance. Here is a blog post by a cosmologist detailing the most striking example of this kind of observation:
http://blogs.discovermagazine.com/cosmicvariance/2006/08/21/dark-matter-exists/
In fact, our observations of dark matter to date are so varied that it is incredibly difficult to come up with any alternative models that are able to explain them all. As Sean Carroll noted, the evidence is now quite strong that dark matter really exists.
I always disliked Dark Matter as too magic and Dark Energy even more so.
While I have no problem acknowledging that there won't be any definite answers for quite some time, a basic principle we simply didn't find yet seems more pleasing than matter we can't find.
Either way, interesting times, etc :)
“Concerning gravity, mainstream physics assumes that there is only one gravitational charge (identified with the inertial mass) while I have assumed that, as in the case of electromagnetic interactions, there are two gravitational charges: positive gravitational charge for matter and negative gravitational charge for antimatter,” Hajdukovic explained.
I've stopped reading after "mainstream physics".
The SM is kludge itself. Not beautiful or intuitive. Check out Hugh Everett III and his removal of the arbitrary wave collapse function.
Come back, Archimedes Plutonium, all is forgiven!
Well, not all, but most.
Well some.
Actually, Archimedes old chap, we didn't exactly "forget" to send you an invite.
"Security!"
Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
fridge just behind the gravity waves
adjective/in'vizbl/
Unable to be seen; not visible to the eye
- this invisible gas is present to some extent in every home
Concealed from sight; hidden
- he lounged in a doorway, invisible in the dark
Invisible does NOT mean undetectable. In addition you make several mistakes in your examples. Iron filings, having no net charge and being conductors, will not line up for an electric field like they do for a magnetic field. You might be able to get them to do ths if you had a strong enough field by inducing a electric dipole in each but this would work for any conductor, not just iron and the picture you link shows a magnetic field from a bar magnet not an electric field at all. However electric fields are easy to detect e.g. they deflect the path of charged particles...but they are still invisible. You see the effects of the field NOT the field itself.
Also spectroscopy in stars you are generally looking at the plasma state, not the gaseous state which is why stars are not transparent: plasma is opaque! However you can detect invisible gases in nebulae from their absorption of non-visible parts of the EM spectrum.
It is indeed possible that there is some underlying property of gravity/space-time which might possibly account for DM. However this would also have to account for observations like the Bullet Cluster (google it) where two galaxies have collided apparently separating the matter made of atoms from the DM. This is extremely hard to account for in a gravity/space-time model since you now need the properties of one area of space to be rather different from another region. In fact I would be concerned that this breaks relativity since is space-time can have properties which vary in a detectable way then I can now use one such region as a reference point and so it risks breaking relativistic invariance (I'm not a GR guy though so I don't know how big an issue this is).