Sure I'd like to start one, but I lack the kazillion dollars needed to bribe Congress - err, promote the concept. You are correct that non-corrupt certifiers are needed if the concept is to work (since we can be fairly certain mandating open source isn't going to work), and your implicit constraint that the incumbents can't be the ones writing the regulations is also very true.
In this case, it's not an impossible task - merely a very very difficult one. Good programming practices are fairly well defined, there are source validators out there, and there are some very respectable vulnerability scanners. These wouldn't eliminate all defects, they might not even eliminate the majority of defects, but the three combined aught to eliminate at a practical cost the majority of defects that can be casually found and exploited by anyone.
Yeah, but how do you get them to actually implement that? People won't stop using Facebook, no matter what security holes there are, so there's no market force you can use, Facebook isn't going to publicly show any kind of audit or QA trail, and you can't enforce what you can't measure. I dislike a lot of the measurements that do exist in the Real World (tm), but that's a problem with the measurement used and not with the idea of measuring in the abstract.
Yes, there's got to be "more than no" QA and it almost doesn't matter how much more than none because any non-zero improvement is an infinite order of magnitude greater than absolute zero, but Facebook is demonstrably not going to implement QA out of being nice or considerate and the A-Team is sadly fictional (though the image of the board of directors being thrown out a window by B.A. is oddly appealing...)
...would be a magnetic map superimposed on an inverse map of known stellar objects where "brightness" is the estimated mass calibrated such that stars that behave as we'd expect them to will show up as black (or near to it). (ie: calculate what you'd hypothesize the magnetic fields "should" be if all models are correct, then look at the difference between what you see and what you expect to see.)
In other words, what doesn't match up? Maps are wonderful things, but in science you really don't care too much about the knowns. The unknowns are much more fun. Knowing where there are magnetic fields where there's no identifiable source, where the magnetic field for stars are unexpectedly strong or unexpectedly weak - that's where it gets really interesting. You can do a lot where data doesn't match the hypothesis. There's a lot less you can do when they do match and there's absolutely nothing you can do if you don't make any predictions at all.
Nonono. It will be irrelevant in the traditional market because the world ends in December 2012 and SP1, the first working version, won't be out before 2013.
The Navier-Stokes equations are definitely chaotic, but turbulence is itself chaotic. It's actually a wonderful example of it.
A physical model would have the same problems, yes, since you can't scale atoms and the sensitivity to initial conditions means that given a long enough run (which is going to depend on the exact nature of the system) the cumulative error will swamp the system. The advantage of physical systems (for now) is that both the step size and the particle size under consideration are considerably smaller and modeled to a far greater level of precision. Physical models are still imperfect and can lead to all kinds of false assumptions if relied upon too heavily, but as the step before the full-scale system, it's the best we currently have.
A 1:1000 model essentially treats a block of 1000 molecules on the full scale as being the same as 1 molecule on the small scale. This means that at 0'C and 1 atmosphere, such a model would consider 2.687 x 10^22 (remember, you're considering 1000 at a time) molecules of an ideal gas per cubic metre of gas under consideration. In comparison, the world's fastest supercomputer can perform around 1 x 10^16 FLOPS and the cartesian form of Navier-Stokes looks to me like you're going to need to perform around 24-25 floating point operations per iteration per molecule. So you're looking at around 600 million seconds per cubic meter of simulated gas flow to get CFD equal to a physical model, if no simplifying assumptions can be made, and that's only true if thee world's fastest supercomputer's FLOPS rating is with a level of floating-point precision great enough not to introduce rounding errors within those 600 million seconds.
Regulating social network software might actually be a good idea. Not as in restricting content, but as in requiring certain standards to be met. Like it or not, we live in a connected world where information is shared, collated and mined. Errors in that data are next to impossible to correct because they spread faster than you can correct them. In the absence of data privacy laws, it is essential that the calibre of software be such that inappropriate access is kept to an absolute minimum.
Having said that, I would argue that this should be coupled with improvements to the way certification programs work. Most of them are too expensive for projects that actually do exist in regulated markets, but obviously you can't make them too cheap because the effort and expense of certification would leave those involved in such efforts open to a social denial-of-service attack.
If social network software had to pass a certification program, the standards required aught to be clearly laid out, the methodologies clearly defined and the certification program stringent enough to be useful but also affordable enough (how doesn't matter) that even a college kid could get one release fully reviewed before going live.
Humans had a huge impact on Mammoths, that's well-established. The standard hunting technique for big game appears to have been to trigger a stampede off a cliff. You should also remember that humans primarily hunted Pygmy Mammoth, not the giant kind, and that humans lived right up to the ice sheet during the Ice Age (and even hunted beyond it). Neandertals and Denisovians were the primary hominids living in extremely cold climates, but modern humans were quite capable of enduring extreme climates provided some sort of food existed. (Fishing from boats turns out to have been an extremely ancient technology.)
Having said that, Mammoth diversity was dropping long before humans even reached places like the Americas, so there were clearly other factors involved.
It's also a great insurance policy, in case the Australian government gets fed up and starts sinking their whaling fleet. It's much harder to sink a Mammoth hunting lodge.
Yes, yes, but you're forgetting that the body armour business will sky-rocket. Can you imagine how much they'd be able to charge a Mammoth for a spear-proof suit?
Any model that is inherently chaotic (read: almost all of them) cannot be simulated on a computer accurately. There will be a cumulative error which will grow extremely rapidly (this is known as the "Butterfly Effect" after a well-meaning but ultimately damaging title of a research paper on the subject). Fluid dynamics is a major headache when it comes to chaotic systems, since the equations are violently unstable at most points most of the time. The only reason anyone can get any work done at all with CFD is that most research groups simplify the equations to one very narrow, very specific range of conditions. Even then, CFD is treated as a first approximation. A physical model of some sort is almost always built, somewhere along the line.
Indeed, one of the unsolved Millenium Challenges is to find out just how bad the Navier-Stokes equations really are. I'd have thought a more interesting challenge would be to find an alternative way to model chaotic systems. (Chaos means that the system is deterministic but not predictable. Which is no different from saying that you have a superposition of probablistic outcomes where the actual outcome is only knowable by observing the system. A field that is of interest to all kinds of people, including physicists and sci-fi writers. A standardized way of dealing with such systems that can yield any additional information at all - doesn't matter what or how little - would have a lot of appeal.)
Now that's entirely fair and I'm happy to support you all the way on that. News vendors have an extraordinary talent for finding the most obscure and dubious preprints for the purpose of making "the discovery of the century"*.
*Until tomorrow, when a new discovery of the century will be made.
This need to sensationalize is absurd. Justifying it on the basis of readership is a bit naff since most people stick to news sources they know and don't switch brands for the purpose of reading crazier-but-truthier stories. The only value is in attracting totally new readers/viewers and you can do that just as well with decent promotion.
Well, now they're banned from going into the woods with strange men, ship-to-ship combat with pirates is their one hope of getting a decent badge. Just don't tell them that these aren't the pirates with ships, you'd break their hearts.
The Bullet Cluster exhibits a distribution of stellar objects and gasses that would not be expected in a routine collision provided certain assumptions are correct, where those assumptions are:
a) That we are interpreting what we are seeing correctly (case in point: irregular galaxies turned out not to be - they were just galaxies of other classifications seen from very odd angles)
b) That the phenomena being observed cannot be explained by standard means (case in point: we're only now understanding the range of high energy jets from stellar objects and new types are being discovered all the time - a new type was found just a week or so ago)
So far, the astronomers seem content that they are indeed interpreting what they see correctly and that the phenomena cannot be explained by standard means. This is why they think dark matter may be involved. The use of dark matter is an "explanation" of what they are seeing and how to reconcile the observable with the theoretical. That is what "explanation" means in science. You do know that, right?
What I have so far failed to see is why dark matter should be part of the explanation at all. I see nothing in any description that I can find that requires that dark matter be the variable and not something else. There may be such a reason, but no sane or rational scientist will ever accept a theory as being sound unless such a reason can be put forward. Nobody needs direct evidence, but they DO need to know what such direct evidence would look like so that when the observations become possible the hypothesis can be tested. (The Big Bang could not be tested at the time it was put forward, but it was a valid theory because it said how you would test the theory once the means became available. A good many of these tests have become possible over the decades and the theory has stood up well to them. That is the mark of GOOD theoretical work.)
I emphasize if it's non-zero, dark matter must be altered at the very least - ie: if there is residual gravity, then dark matter theories MUST compensate for the change in the gravitational field. It may be that no such solution exists - ie: in order to produce the correct values for other elements of the theory, you HAVE to have a gravitational field of such-and-such value which is in excess of what is permitted once the residuals are taken into account. This is where the remainder of "and may even be entirely disposed of" kicks in. If there simply isn't a solution that satisfies the system of equations, then the amount of dark matter is zero. It would be the only solution that works.
It is my contention that the paper is NOT of any groundbreaking interest, that at the very most it eliminates meta-stable solutions. (A meta-stable solution is a solution which is stable at specific points only. It is not stable if you deviate from those points to any degree whatsoever. Balancing a pencil on an infinitely sharp point where this places the centre of gravity and centre of mass on a perfectly vertical line from that point is meta-stable. If there is absolutely zero force, it will remain exactly where it is, hence the stable part. It is not unstable as it will not change state on its own. However, an electron passing through it would be enough to knock it over, hence the meta part. Any external force or field is enough to break the symmetry and produce instability.)
Now, I emphasize that "at most it eliminates meta-stable solutions". It doesn't do this if your series sums to zero even if intermediate summations are non-zero. Chaotic systems are not nice and you can make no assumption about the sum to infinity merely from examining a few data points. The paper has NO meaning if the sum at infinity is zero, whether it is zero because the components are zero or because the chaotic system happens to produce a zero.
I have read the paper and there is nothing wrong with reading arXiv preprints. That's where the proof of Poincare's Conjecture was published, after all. Not satisfied? Ok, is there anything in arXiv that is less reputable than anything you might find in the letters page in Nature? My guess is that the answer is no, since the letters don't include the reasoning. Yet most reputable scientists would consider the letters page to be extremely valuable secondary information. It's not peer-reviewed, but it IS important. arXiv is no different, other than having the reasoning as well. It should NOT be treated as equal to a peer-reviewed paper, it should be treated as a letter to a serious scientific journal. Nothing more, nothing less.
I consider bias to be a nonsense in science. Bias has no place in the study of things. Weigh things appropriately, but let no weight be zero or infinity. Correct weighting the evidence isn't bias, it is the elimination of bias by multiplying by the reciprocal of the noise.
Supersymmetry is problematic as the simplest forms are now falsified by the LHC. You have to assume a more complex form - which is valid, but I have seen no evidence that the CDM theory has been re-examined to see what the impact of the LHC observations is.
The Bullet cluster obviously needs explaining, but I saw nothing on the Wikipedia page that indicated why Dark Matter was needed as a part of that explanation. There is clearly a drag effect of some sort, but there are plenty of potential causes of drag. Which ones are viable depend on the precise angle of each galaxy at the time of collision and the probability based on known classes of stellar object of various types of high-pressure event occurring. I would imagine that such work has been done but Wikipedia showed none that I could see.
CMB is a problem because certain fluctuations could potentially be the result of specific multiverse theories being correct. Due to the lack of ability to see multiverses, CMB alone is not a valuable indicator because you cannot test the different hypotheses. There's no means of distinguishing a valid model from an invalid one. I am not saying CMB isn't a demonstration of dark matter, merely that it is only suggestive of being a demonstration of dark matter. Until such time that enough observations have dark matter as the only common suggested solution to all of them, the best you can say is that CMB allows for the possibility of dark matter.
Recent observations fail to observe dark matter anywhere but do detect a provable absence of it around dwarf galaxies and globular clusters. This is a major problem for dark matter and may yet prove to be fatal to the theory.
Secondly, a theory should always be as simple as possible but no simpler (Bert Einstein) and should contain no unnecessary elements (William of Occam), which is essentially the same thing. Adding in variables is complexity and it is not merely rational but absolutely key to the entire basis of the Scientific Method (in which falsification is king) to attempt to produce models that are simpler but not too simple to actually hold up. It is NOT enough to test the theory directly, you MUST test the hypothesis that simpler theories that are just as accurate exist. It is only by showing no such theory exists that you can be satisfied that you have met both these key tests.
Your attitude is, I have to say, EXTREMELY unscientific and I am ashamed of being on a board with such totally immature minds.
The paper is comprehensible to anyone who has completed O-Level maths or physics. The paper deals almost entirely with resultant forces and you can handle resultants if you can handle addition, Pythagoras' Theorum and Cartesian notation. There's very little complexity in the concepts.
The most complex part is what they call "fractal" (which should actually be called "self-similar"). A self-similar structure is one which is comprised of parts that resemble the whole. What they're using that for is to create a series. If you have galaxies placed at A, B, C and D, then you can figure out where galaxy E, F, G and H would be. And if you're really clever, you can sum the series to infinity. In other words, provided the pattern continues, you can calculate the net gravitational pull of all the galaxies along any given line. Understanding arithmetic and geometric series might be taught later in some schools, but any poster here over 18 who has studied maths and physics to that point will have covered them.
That's it. That's everything you really need to know to understand the paper. The rest of it (dealing with the specific equations used to figure out the specific gravitational pull on a specific particle, etc) is simply not that important outside of a physics lab. Insofar as Slashdotters or other outside observers are concerned, what matters is whether the resultant gravitational vector is zero (the current standard model) or non-zero (the model presented in the paper). If it's zero, dark matter survives the challenge. If it's non-zero, dark matter must be altered at the very least and may even be entirely disposed of.
Not sure about the summary, but the paper is extremely simple. I'll summarize it:
It is commonly assumed that galaxies are evenly distributed. This would mean that if you picked any galaxy at random, you could pick other galaxies whose gravitational pull totally balanced out the effect of the first one. So, overall, no distant galaxy would ever affect anything.
What is observed is that galaxies are NOT evenly distributed. There is, indeed, left-over gravitational pull. Provided the distribution of galaxies is self-similar (which is what they mean by "fractal", since "fractal" itself has no meaning here) AND a few other constraints are valid, THEN the left-over gravitational pull would be enough to explain the rotation of the stars and gasses within the galaxy. The author's analysis of the galaxies over a relatively nearby region of space suggests to him that the distribution is indeed self-similar.
(Summary off, analysis on)
Is this a new theory? As a replacement for Dark Matter, yes. In any other context, no. Shepherding moons/asteroids dominate our own solar system, creating a dynamic that would be utterly unstable without them. Shepherding galaxies and super-galaxies is a new one, but if the physics is observed in other systems then the physics must be considered sound. The only question I see here is whether the distribution of galaxies is indeed self-similar. If it isn't, the theory is wrong. If it is, then dark matter - as it is currently understood - must be wrong because you now have left-over gravity and you have to alter the dark matter theory to allow for it.
Doesn't the dark matter theory fit things well as it is? No it doesn't. Dwarf galaxies and globular clusters exhibit NONE of the signs assumed to indicate the presence of dark matter. Some don't have high-speed rotation at all. Dark matter theory cannot explain either of these and the usual answer is to say that dark matter "isn't uniform" without ever explaining why it should be missing only with certain classes of structure and not others. It's actually much easier to say that "excess" rotational velocity is a function of residual gravity and that where you have little residual gravity you have no excess rotational velocity. It is also entirely plausible to argue that "null points" are backwaters and that this explains why you get relatively few major galaxies appearing at such points but do get minor multi-stellar structures.
Slashdot Mirror
I'm more inclined to think that the trains in Australia are carrying viruses and simply infect the USB sticks on contact.
Sure I'd like to start one, but I lack the kazillion dollars needed to bribe Congress - err, promote the concept. You are correct that non-corrupt certifiers are needed if the concept is to work (since we can be fairly certain mandating open source isn't going to work), and your implicit constraint that the incumbents can't be the ones writing the regulations is also very true.
In this case, it's not an impossible task - merely a very very difficult one. Good programming practices are fairly well defined, there are source validators out there, and there are some very respectable vulnerability scanners. These wouldn't eliminate all defects, they might not even eliminate the majority of defects, but the three combined aught to eliminate at a practical cost the majority of defects that can be casually found and exploited by anyone.
What's really impressive is that plants started using quantum effects before there were any cats.
Yeah, but how do you get them to actually implement that? People won't stop using Facebook, no matter what security holes there are, so there's no market force you can use, Facebook isn't going to publicly show any kind of audit or QA trail, and you can't enforce what you can't measure. I dislike a lot of the measurements that do exist in the Real World (tm), but that's a problem with the measurement used and not with the idea of measuring in the abstract.
Yes, there's got to be "more than no" QA and it almost doesn't matter how much more than none because any non-zero improvement is an infinite order of magnitude greater than absolute zero, but Facebook is demonstrably not going to implement QA out of being nice or considerate and the A-Team is sadly fictional (though the image of the board of directors being thrown out a window by B.A. is oddly appealing...)
...would be a magnetic map superimposed on an inverse map of known stellar objects where "brightness" is the estimated mass calibrated such that stars that behave as we'd expect them to will show up as black (or near to it). (ie: calculate what you'd hypothesize the magnetic fields "should" be if all models are correct, then look at the difference between what you see and what you expect to see.)
In other words, what doesn't match up? Maps are wonderful things, but in science you really don't care too much about the knowns. The unknowns are much more fun. Knowing where there are magnetic fields where there's no identifiable source, where the magnetic field for stars are unexpectedly strong or unexpectedly weak - that's where it gets really interesting. You can do a lot where data doesn't match the hypothesis. There's a lot less you can do when they do match and there's absolutely nothing you can do if you don't make any predictions at all.
First, Quantum Mechanics is chaotic. Second, probability waves are a product of Information Theory.
Nonono. It will be irrelevant in the traditional market because the world ends in December 2012 and SP1, the first working version, won't be out before 2013.
The Navier-Stokes equations are definitely chaotic, but turbulence is itself chaotic. It's actually a wonderful example of it.
A physical model would have the same problems, yes, since you can't scale atoms and the sensitivity to initial conditions means that given a long enough run (which is going to depend on the exact nature of the system) the cumulative error will swamp the system. The advantage of physical systems (for now) is that both the step size and the particle size under consideration are considerably smaller and modeled to a far greater level of precision. Physical models are still imperfect and can lead to all kinds of false assumptions if relied upon too heavily, but as the step before the full-scale system, it's the best we currently have.
A 1:1000 model essentially treats a block of 1000 molecules on the full scale as being the same as 1 molecule on the small scale. This means that at 0'C and 1 atmosphere, such a model would consider 2.687 x 10^22 (remember, you're considering 1000 at a time) molecules of an ideal gas per cubic metre of gas under consideration. In comparison, the world's fastest supercomputer can perform around 1 x 10^16 FLOPS and the cartesian form of Navier-Stokes looks to me like you're going to need to perform around 24-25 floating point operations per iteration per molecule. So you're looking at around 600 million seconds per cubic meter of simulated gas flow to get CFD equal to a physical model, if no simplifying assumptions can be made, and that's only true if thee world's fastest supercomputer's FLOPS rating is with a level of floating-point precision great enough not to introduce rounding errors within those 600 million seconds.
Regulating social network software might actually be a good idea. Not as in restricting content, but as in requiring certain standards to be met. Like it or not, we live in a connected world where information is shared, collated and mined. Errors in that data are next to impossible to correct because they spread faster than you can correct them. In the absence of data privacy laws, it is essential that the calibre of software be such that inappropriate access is kept to an absolute minimum.
Having said that, I would argue that this should be coupled with improvements to the way certification programs work. Most of them are too expensive for projects that actually do exist in regulated markets, but obviously you can't make them too cheap because the effort and expense of certification would leave those involved in such efforts open to a social denial-of-service attack.
If social network software had to pass a certification program, the standards required aught to be clearly laid out, the methodologies clearly defined and the certification program stringent enough to be useful but also affordable enough (how doesn't matter) that even a college kid could get one release fully reviewed before going live.
It didn't. It took that long for the "popular bodybuilding forum" to archive those pictures guaranteed to improve its popularity.
Those were Pygmy Mammoth, which is not the same species as the Woolly Mammoth.
Humans had a huge impact on Mammoths, that's well-established. The standard hunting technique for big game appears to have been to trigger a stampede off a cliff. You should also remember that humans primarily hunted Pygmy Mammoth, not the giant kind, and that humans lived right up to the ice sheet during the Ice Age (and even hunted beyond it). Neandertals and Denisovians were the primary hominids living in extremely cold climates, but modern humans were quite capable of enduring extreme climates provided some sort of food existed. (Fishing from boats turns out to have been an extremely ancient technology.)
Having said that, Mammoth diversity was dropping long before humans even reached places like the Americas, so there were clearly other factors involved.
It's also a great insurance policy, in case the Australian government gets fed up and starts sinking their whaling fleet. It's much harder to sink a Mammoth hunting lodge.
Yes, yes, but you're forgetting that the body armour business will sky-rocket. Can you imagine how much they'd be able to charge a Mammoth for a spear-proof suit?
I hope they remembered to pay the estate of Emperor Norton royalties (imperialties?) for the bridge.
Any model that is inherently chaotic (read: almost all of them) cannot be simulated on a computer accurately. There will be a cumulative error which will grow extremely rapidly (this is known as the "Butterfly Effect" after a well-meaning but ultimately damaging title of a research paper on the subject). Fluid dynamics is a major headache when it comes to chaotic systems, since the equations are violently unstable at most points most of the time. The only reason anyone can get any work done at all with CFD is that most research groups simplify the equations to one very narrow, very specific range of conditions. Even then, CFD is treated as a first approximation. A physical model of some sort is almost always built, somewhere along the line.
Indeed, one of the unsolved Millenium Challenges is to find out just how bad the Navier-Stokes equations really are. I'd have thought a more interesting challenge would be to find an alternative way to model chaotic systems. (Chaos means that the system is deterministic but not predictable. Which is no different from saying that you have a superposition of probablistic outcomes where the actual outcome is only knowable by observing the system. A field that is of interest to all kinds of people, including physicists and sci-fi writers. A standardized way of dealing with such systems that can yield any additional information at all - doesn't matter what or how little - would have a lot of appeal.)
Now that's entirely fair and I'm happy to support you all the way on that. News vendors have an extraordinary talent for finding the most obscure and dubious preprints for the purpose of making "the discovery of the century"*.
*Until tomorrow, when a new discovery of the century will be made.
This need to sensationalize is absurd. Justifying it on the basis of readership is a bit naff since most people stick to news sources they know and don't switch brands for the purpose of reading crazier-but-truthier stories. The only value is in attracting totally new readers/viewers and you can do that just as well with decent promotion.
Well, now they're banned from going into the woods with strange men, ship-to-ship combat with pirates is their one hope of getting a decent badge. Just don't tell them that these aren't the pirates with ships, you'd break their hearts.
The Bullet Cluster exhibits a distribution of stellar objects and gasses that would not be expected in a routine collision provided certain assumptions are correct, where those assumptions are:
a) That we are interpreting what we are seeing correctly (case in point: irregular galaxies turned out not to be - they were just galaxies of other classifications seen from very odd angles)
b) That the phenomena being observed cannot be explained by standard means (case in point: we're only now understanding the range of high energy jets from stellar objects and new types are being discovered all the time - a new type was found just a week or so ago)
So far, the astronomers seem content that they are indeed interpreting what they see correctly and that the phenomena cannot be explained by standard means. This is why they think dark matter may be involved. The use of dark matter is an "explanation" of what they are seeing and how to reconcile the observable with the theoretical. That is what "explanation" means in science. You do know that, right?
What I have so far failed to see is why dark matter should be part of the explanation at all. I see nothing in any description that I can find that requires that dark matter be the variable and not something else. There may be such a reason, but no sane or rational scientist will ever accept a theory as being sound unless such a reason can be put forward. Nobody needs direct evidence, but they DO need to know what such direct evidence would look like so that when the observations become possible the hypothesis can be tested. (The Big Bang could not be tested at the time it was put forward, but it was a valid theory because it said how you would test the theory once the means became available. A good many of these tests have become possible over the decades and the theory has stood up well to them. That is the mark of GOOD theoretical work.)
I emphasize if it's non-zero, dark matter must be altered at the very least - ie: if there is residual gravity, then dark matter theories MUST compensate for the change in the gravitational field. It may be that no such solution exists - ie: in order to produce the correct values for other elements of the theory, you HAVE to have a gravitational field of such-and-such value which is in excess of what is permitted once the residuals are taken into account. This is where the remainder of "and may even be entirely disposed of" kicks in. If there simply isn't a solution that satisfies the system of equations, then the amount of dark matter is zero. It would be the only solution that works.
It is my contention that the paper is NOT of any groundbreaking interest, that at the very most it eliminates meta-stable solutions. (A meta-stable solution is a solution which is stable at specific points only. It is not stable if you deviate from those points to any degree whatsoever. Balancing a pencil on an infinitely sharp point where this places the centre of gravity and centre of mass on a perfectly vertical line from that point is meta-stable. If there is absolutely zero force, it will remain exactly where it is, hence the stable part. It is not unstable as it will not change state on its own. However, an electron passing through it would be enough to knock it over, hence the meta part. Any external force or field is enough to break the symmetry and produce instability.)
Now, I emphasize that "at most it eliminates meta-stable solutions". It doesn't do this if your series sums to zero even if intermediate summations are non-zero. Chaotic systems are not nice and you can make no assumption about the sum to infinity merely from examining a few data points. The paper has NO meaning if the sum at infinity is zero, whether it is zero because the components are zero or because the chaotic system happens to produce a zero.
I have read the paper and there is nothing wrong with reading arXiv preprints. That's where the proof of Poincare's Conjecture was published, after all. Not satisfied? Ok, is there anything in arXiv that is less reputable than anything you might find in the letters page in Nature? My guess is that the answer is no, since the letters don't include the reasoning. Yet most reputable scientists would consider the letters page to be extremely valuable secondary information. It's not peer-reviewed, but it IS important. arXiv is no different, other than having the reasoning as well. It should NOT be treated as equal to a peer-reviewed paper, it should be treated as a letter to a serious scientific journal. Nothing more, nothing less.
I consider bias to be a nonsense in science. Bias has no place in the study of things. Weigh things appropriately, but let no weight be zero or infinity. Correct weighting the evidence isn't bias, it is the elimination of bias by multiplying by the reciprocal of the noise.
Where, precisely, do I suggest tossing out GR? In fact, where in my post do I suggest tossing out anything other than poor practices?
Supersymmetry is problematic as the simplest forms are now falsified by the LHC. You have to assume a more complex form - which is valid, but I have seen no evidence that the CDM theory has been re-examined to see what the impact of the LHC observations is.
The Bullet cluster obviously needs explaining, but I saw nothing on the Wikipedia page that indicated why Dark Matter was needed as a part of that explanation. There is clearly a drag effect of some sort, but there are plenty of potential causes of drag. Which ones are viable depend on the precise angle of each galaxy at the time of collision and the probability based on known classes of stellar object of various types of high-pressure event occurring. I would imagine that such work has been done but Wikipedia showed none that I could see.
CMB is a problem because certain fluctuations could potentially be the result of specific multiverse theories being correct. Due to the lack of ability to see multiverses, CMB alone is not a valuable indicator because you cannot test the different hypotheses. There's no means of distinguishing a valid model from an invalid one. I am not saying CMB isn't a demonstration of dark matter, merely that it is only suggestive of being a demonstration of dark matter. Until such time that enough observations have dark matter as the only common suggested solution to all of them, the best you can say is that CMB allows for the possibility of dark matter.
Recent observations fail to observe dark matter anywhere but do detect a provable absence of it around dwarf galaxies and globular clusters. This is a major problem for dark matter and may yet prove to be fatal to the theory.
Secondly, a theory should always be as simple as possible but no simpler (Bert Einstein) and should contain no unnecessary elements (William of Occam), which is essentially the same thing. Adding in variables is complexity and it is not merely rational but absolutely key to the entire basis of the Scientific Method (in which falsification is king) to attempt to produce models that are simpler but not too simple to actually hold up. It is NOT enough to test the theory directly, you MUST test the hypothesis that simpler theories that are just as accurate exist. It is only by showing no such theory exists that you can be satisfied that you have met both these key tests.
Your attitude is, I have to say, EXTREMELY unscientific and I am ashamed of being on a board with such totally immature minds.
The paper is comprehensible to anyone who has completed O-Level maths or physics. The paper deals almost entirely with resultant forces and you can handle resultants if you can handle addition, Pythagoras' Theorum and Cartesian notation. There's very little complexity in the concepts.
The most complex part is what they call "fractal" (which should actually be called "self-similar"). A self-similar structure is one which is comprised of parts that resemble the whole. What they're using that for is to create a series. If you have galaxies placed at A, B, C and D, then you can figure out where galaxy E, F, G and H would be. And if you're really clever, you can sum the series to infinity. In other words, provided the pattern continues, you can calculate the net gravitational pull of all the galaxies along any given line. Understanding arithmetic and geometric series might be taught later in some schools, but any poster here over 18 who has studied maths and physics to that point will have covered them.
That's it. That's everything you really need to know to understand the paper. The rest of it (dealing with the specific equations used to figure out the specific gravitational pull on a specific particle, etc) is simply not that important outside of a physics lab. Insofar as Slashdotters or other outside observers are concerned, what matters is whether the resultant gravitational vector is zero (the current standard model) or non-zero (the model presented in the paper). If it's zero, dark matter survives the challenge. If it's non-zero, dark matter must be altered at the very least and may even be entirely disposed of.
Not sure about the summary, but the paper is extremely simple. I'll summarize it:
It is commonly assumed that galaxies are evenly distributed. This would mean that if you picked any galaxy at random, you could pick other galaxies whose gravitational pull totally balanced out the effect of the first one. So, overall, no distant galaxy would ever affect anything.
What is observed is that galaxies are NOT evenly distributed. There is, indeed, left-over gravitational pull. Provided the distribution of galaxies is self-similar (which is what they mean by "fractal", since "fractal" itself has no meaning here) AND a few other constraints are valid, THEN the left-over gravitational pull would be enough to explain the rotation of the stars and gasses within the galaxy. The author's analysis of the galaxies over a relatively nearby region of space suggests to him that the distribution is indeed self-similar.
(Summary off, analysis on)
Is this a new theory? As a replacement for Dark Matter, yes. In any other context, no. Shepherding moons/asteroids dominate our own solar system, creating a dynamic that would be utterly unstable without them. Shepherding galaxies and super-galaxies is a new one, but if the physics is observed in other systems then the physics must be considered sound. The only question I see here is whether the distribution of galaxies is indeed self-similar. If it isn't, the theory is wrong. If it is, then dark matter - as it is currently understood - must be wrong because you now have left-over gravity and you have to alter the dark matter theory to allow for it.
Doesn't the dark matter theory fit things well as it is? No it doesn't. Dwarf galaxies and globular clusters exhibit NONE of the signs assumed to indicate the presence of dark matter. Some don't have high-speed rotation at all. Dark matter theory cannot explain either of these and the usual answer is to say that dark matter "isn't uniform" without ever explaining why it should be missing only with certain classes of structure and not others. It's actually much easier to say that "excess" rotational velocity is a function of residual gravity and that where you have little residual gravity you have no excess rotational velocity. It is also entirely plausible to argue that "null points" are backwaters and that this explains why you get relatively few major galaxies appearing at such points but do get minor multi-stellar structures.