CERN Physicist Says Dark Matter May Be an Illusion 379
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."
If you can't handle the concept of dark matter (Score:4, Interesting)
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.
Re:no dark matter... (Score:4, Interesting)
I'd love to see how his model explains something like (e.g) the Bullet Cluster [wikipedia.org], because quite frankly I don't think it does - the article states that his theory explains the speeding up of galactic rotation (the reason why we first hypothesized dark matter), but the article goes on to state that his hypothesis doesn't actually cover a ton of other stuff like the CMB.
Furthermore, this theory is based on the hypothesis that matter and antimatter are gravitationally repulsive, which (imo) is absolute BS. It's true, we haven't generated enough antimatter yet to know for a fact that it acts the same way as regular matter in a gravitational field generated by regular matter, but we have absolutely no reason to think that it would be gravitationally repulsive. If that turns out to be true, there will need to be a shit-ton of rejiggering of models and basically everything we think we know about physics will have to be moved around.
Basically, he's said "If pigs can levitate, then I can account for the discrepancy in galactic rotation curves without dark matter" - except if pigs can levitate, we'll need to rethink everything anyway.
Re:no dark matter... (Score:5, Interesting)
Uhh, well. Scientists never actually claim to "know" the truth about anything completely, they just claim to know "an approximation of the truth" which is a theory or axiom that has been tested and shown to work in every case its been tested in so far. People still continue to test it and find it works. GPS satellites would not work if Relativity was not mostly correct. Don't get confused with the word "approximation of truth", it doesn't mean its not correct to a degree. There is no absolute right and absolute wrong.
The principal of science is that you seek truth through observable, repeatable experiments. We know gravity exists on Earth because every time we throw a rock in the air it falls back to the ground. If one day, it did not fall back to the ground, or it fell to the ground 50 percent of the time and the other 50 percent of the time it flew off into space; we would probably not believe gravity existed and instead either have worked on or be working on other explanations. For example, Relativity has passed just about every test its been put through except for things on quantum scale or on super-massive scale. Does this mean it is wrong? No. It means that it is right in certain situations, but not in others. If you know anything about mathematics, which is totally based in rigorously proved logic that is basically irrefutable once its axioms and assumptions are cemented, you will realize that sometimes its possible to be correct within a certain degree or domain but incorrect beyond it.
Its a bit different to claim many of the things religions claim. For example, claiming a flood wiped out all humans on Earth except for Noah, his sons, and all of their spouses along with two of each animal is ludicrous. The fossil record shows absolutely no evidence of this and a global flood poses other physical questions that have completely unfeasible explanations, and its been proven so if you actually read about scientific topics such as genetics, biology, anthropology, paleontology, and physics/geophysics/meteorology (particularly atmospheric pressure). They don't specifically say that the flood didn't happen, nor do they attack it. They just show certain timelines for fossils, or certain geological strata or certain physical relationships (in the form of equations) that make something like a global flood seem ridiculous. Maybe it happened on a smaller scale, but your will find its absurd to think it happened over the whole earth.
You see, religions claim to "know" things and require absolutely no proof at all other than faith; which is belief without evidence. They won't admit when they are wrong even in the face of overwhelming evidence against their belief. That's not to say scientists don't believe things too and sometimes be stubborn about changing them, its just that religions don't believe things based on logic and evidence whatsoever. Even scientists are humans, and make errors sometimes. However, their training helps them remove illogical or absurd things from their minds rather than hold on to them when overwhelming evidence is put in their face. I don't think that religious fanatics are incapable of being as smart as scientists, I just think many of them are brainwashed or undereducated.
Does all of this mean God doesn't exist? No. Its just that there is no evidence of them existing, nor is there necessarily a reason they must exist. I for one am not sure. I admit it is possible, but I have not seen evidence to support it nor do I see a theory that holds up when tested that shows there must be one. Some people choose to believe there is no God, some people believe there probably is, and some people simply don't know. Whatever you believe is what you believe, but please don't assume that scientists are out to get you, or make you change, or disprove god. By definition the existence of God couldn't be proved anyway, since even if we "found God", how do you know its not just a super-advanced alien being? Even if their is an afterlife you won't truly know if God exists because for all yo
Re:no dark matter... (Score:4, Interesting)
Re:Can't see the quantum vacuum for the dark matte (Score:5, Interesting)
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 [wikipedia.org] a century too late.
The latest attempts to explain dark matter are an ever bigger joke, like Modified Newtonian dynamics [wikipedia.org]. 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 [wikipedia.org]. 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?
digravitational constant of vacuum is not 1? (Score:4, Interesting)
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.
Re:no dark matter... (Score:2, Interesting)
Now compare this to religion. Religion states that there are things that are part of reality that we cannot sense or understand. Basically saying that are senses aren't flawed per se, they are just somehow insufficient and thus cannot observe the "higher" powers etc.....
To put it in a sound bite, science requires you to believe what you can sense, and only what you can sense is real, religion requires you to believe there are things that are real that you cannot sense. These are two very different interpretations of the words "faith" and "knowledge"
Re:no dark matter... (Score:2, Interesting)
There's another significant difference between the religious (the fundamentalists in particular) and scientists-- As a general rule, Scientists have a reasonably complete understanding of the subject we're using to categorize them. This typically isn't true of the religious. It's a different mindset entirely-- Scientists seek to understand their world. The religious stereotype seeks a cause to rally around, so they can ignore their own faults (and possibly concentrate on the faults of others, instead). The real problems begin when a religious leader fits this stereotype. That's when you get racist cults, terrorist attacks and abortion clinic bombings.
I think the largest problem is that people believe that Religion should explain Scientific matters. The fact is that religious scriptures are pretty good at giving instructions and advice, but they're pretty vague on the details of the origins of the universe. Christian scriptures say that God is responsible for creating everything and they also provide a pretty vague sequence of events, but they don't explain about gravitational forces or (perhaps infamously) magnets.
Religion also poses some peculiar challenges for Science-- One approach to proving the tenets of a religion might include proving the existence of the human soul. If a person asked a scientist for the measurements of a "homwhart", then he would likely want to know first of all, "what is a homwhart?", and second, "how do I measure it?" The human soul has very much the same problem. It's said to be something which everyone possesses, but we don't really know what properties it has which can be quantified. How does one approach that scientifically?
Making observations in science (Score:0, Interesting)
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. :-)