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30 Comments
- Ghostalker, on 11/07/2009, -0/+19I don't think a zombie Newton is going to solve anything....
- greywren, on 11/07/2009, -0/+17OK folks, I'm an actual astronomer specializing in galaxy dynamics, so let me break this down for you. MOND was introduced to account for flat galaxy rotation curves in the absence of dark matter, at which it was very successful. However, MOND has failed to properly account for the motions of clusters of galaxies, while the LCDM (Lambda Cold Dark Matter) theory offers a better fit to the data. In addition, contrary to what is sometimes assumed, LCDM has made a number of predictions that have now been verified. The density of dark matter haloes in the outer regions has been found to be consistent with LCDM. In addition, simulations of the large scale structure of the universe display a pattern of voids and clumps strung together by filaments of dark matter, along which a large number of galaxies are expected to lie. This has been observed - galaxies do appear to lie along filaments. And of course, there's the bullet cluster and gravitational lensing.
Here's MOND's real problem: it was intended to be a very simple theory (one free parameter) that could account for observed galaxy dynamics. However, you need to keep changing it and adding more free parameters to account for the other stuff that dark matter explains naturally. What's more, there's no reason to actually think that gravity must be modified as MOND states - it's purely ad hoc. However, there are a number of well-motivated candidates for what might constitute dark matter, namely axions, WIMPS, etc, all of which have been postulated for decades by particle physicists independent of the dark matter hypothesis.
So now, you have a theory that want to make an ad hoc modification to the law of gravity to fit the data and that requires a bunch of extra parameters to make it work right, or you can explain all this stuff with dark matter naturally without having to change the laws of physics. We can't see it, but we have a good idea what it has to be made up of.
Do you see now why most astronomers don't take MOND very seriously? - jas2701, on 11/07/2009, -1/+11People who believe the Dayton Miller's aether experiments are quacks. Not only were many others doing aether experiments at the time and getting null results, but no one ever stopped.
In particular Michelson Morley experiments, Hammar experiments and Kennedy-Thorndike experiments are still carried out repeatedly, with ever increasing accuracy and sophistication (often by graduate students as an exercise) and all get null results. Not only that but CERN and all the other particle physics groups were conducting experiments on the relativistic dynamics of particles up until the 80s until they decided it wasn't worth trying to find anything wrong with it anymore.
I can't tell you much about general relativity since cosmology isn't my stong point, but special relativity (in the relevant special circumstances) is pretty much set in stone by experimental evidence; and it took decades. The only logical conclusion from where I'm sitting is that Dayton Miller ***** up.
The point is that some established physics has such a weight of evidence behind it that it cannot be realistically challenged, and only modified in subtle ways. Since we know general relativity works in certain circumstances (a fairly broad set of circumstances), then not only should a new theory reproduce the same results in that regime, but it should do it in a logical, consistent and simple way. As it said in the article, the MOND models introduce so many degrees of freedom and ad hoc explantions in order to reproduce the observed behaviour (and ends up looking a lot like general relativity as a result), it's barely worth considering as a competitor.
So, if you set out to prove something like the second law of thermodynamics wrong, it's really not worth the funding money. - pln2bz, on 11/06/2009, -8/+17Re: "The review goes a bit further and points out that, to account for all the possible issues, a fully relativistic MOND hypothesis must be derived—for MOND, or any new theory of gravity, to be taken seriously it must contain, as a subset, Einstein's theory of general relativity."
And this is precisely where they consistently go wrong. If you're going to go out of your way to consider MOND, then why constrain your investigation to MOND theories which only support Relativity? Why do they not also revisit the Dayton Miller experiment that generated a non-null result for an aether drift? Given the precision of electronics today, it would make a lot of sense to try to replicate Miller's experiment with a non-hostile, open mind.
The simple explanation for why this is not being done pertains to the continuing heresy associated with questioning strongly entrenched, long-held, established views pertaining to Einstein. Some physics textbooks go so far as to claim that people who believe in Dayton Miller's aether experiments are quacks, even as quantum physicists publish press releases explaining that they can light a light bulb with "energy from the vacuum". The arguments supposedly disqualifying the aether were in fact incredibly weak. Even Einstein himself held out for a replication of Miller's aether drag experiment. But ultimately, Einstein's followers would decide not to follow up on that successful experiment, instead declaring that the aether was dead in a research review paper. Nowadays, Einstein's followers eagerly ridicule the notion of a unified field theory (like an Electrically Modified Newtonian Dynamics, aka EMOND). They fail to acknowledge that Einstein himself came up with the idea. The history of science is not always a straight, narrow, forged path lacking erroneous diversions.
It's really too bad that the physics establishment does not take a hard, introspective look at itself. Many great ideas are being disqualified from funding purely because of their potential for disproving the prior work of established physicists. It won't be until physicists learn to be more honest with themselves that the answers to the hardest questions mankind has ever asked will reveal themselves. Peer review is really nothing more than a group of men. It is not impervious to mistake -- even, in some instances, dramatic mistakes that have persisted for a hundred years. The history of science records many similar mistakes. Just because we have cellphones and computers now does not mean that we are now impervious to similar errors. - DanielPhermous, on 11/07/2009, -0/+8There's a quote from Terry Pratchett that I always find to ring true for me...
"When cosmologists have to postulate bizarre 'dark matter' to explain why galaxies don't obey the laws of gravity, and then throw in even weirder 'dark energy' to explain why galaxies are moving apart at an increasing rate, and when the independent evidence for these two powers of darkness is pretty much non-existent, you can SMELL the paradigm shift coming" - EvilMerodach, on 11/07/2009, -0/+6greywren is undoubtedly right. Also, MOND has to contort itself all out of shape to accommodate the Bullet Cluster findings. MOND is quickly becoming overly complex and inelegant, something that a theory of gravity should not be.
Perhaps because of the name, most people think dark matter is some mumbo-jumbo stuff that astronomers and physicists have made up to explain something they don't understand. Naturally, this isn't true.
Dark matter is thought to be non-baryonic matter. Non-baryonic matter, unlike the matter we see around us, does not interact with the electromagnetic force, and so it is described as "dark" -- we can't see it directly. While this sounds mysterious, neutrinos are also a form of non-baryonic matter. Neutrinos were first proposed back in 1934 as a means to explain the missing energy during beta decay. Today we have "neutrino observatories" that detect neutrino collisions with atomic nuclei. Undoubtedly we'll be detecting dark matter particles in a similar fashion in the very near future. - APODNereid, on 11/09/2009, -0/+4Something (or some things) does not compute.
"the notion of a unified field theory (like an Electrically Modified Newtonian Dynamics, aka EMOND)" and "Electrically Modified Newtonian Dynamics merely refers to gravity as a side-effect of electromagnetism" seem inconsistent ... how does the latter make EMOND a unified field theory?
Then there's the idea that ApJ would not publish a Thornhill paper on EMOND; maybe they would, maybe they wouldn't ... did Thornhill try submitting a paper on EMOND to ApJ?
In any case, is there anything more to EMOND than what is written on those two webpages? For example, does Thornhill propose any testable hypotheses, anywhere?
Tom Bridgman has a blog which contains many entries on the published ideas of Thornhill and Scott, it makes very interesting reading (not least because Tom points out all sorts of internal inconsistencies, fundamental disagreements between Thornhill and Scott, widespread misunderstanding of electromagnetism, and more). Interested readers can find the blog here:
http://dealingwithcreationisminastronomy.blogspot. ...
In one of the links, from pln2bz' comment, Thornhill mentions 'electric gravity' (or some such), and provides the briefest of simple word sketches of the idea. This is not the time to go into it (maybe a in a later comment), but readers may find it amusing that Thornhill seems to be unaware that this idea has a quite long history ... and can be fairly easily shown to be inconsistent with a wide range of well-established observations and experimental results ...
pln2bz, if I may say so, you spend a lot of angry words on what you see as wrong, in contemporary astrophysics (and more), yet provide very few concrete details of what you think should take its place. Even more curious, when I look at what little you do provide in the way of concrete details on alternatives, I find lots of ignorance, many false claims, and much inconsistency. Wouldn't it be a better use of your time if you offered to use your professional skills, as an engineer, to help Thornhill et al.? - APODNereid, on 11/08/2009, -0/+3Re: "Einstein's followers eagerly ridicule the notion of a unified field theory (like an Electrically Modified Newtonian Dynamics, aka EMOND)."
In 1983, Mordehai Milgrom published, in the Astrophysics Journal, a paper titled "A modification of the Newtonian dynamics as a possible alternative to the hidden mass hypothesis". This is where MOND was first published, and explained. ADS says it has been cited 728 times. Of the 728 citations, none has "EMOND" or "Electrically" in its title.
Where is a definitive presentation of EMOND to be found? - DaviDTC, on 11/07/2009, -3/+5What he said, I think.
- JigoroKano, on 11/07/2009, -1/+3Everything you have said is wrong and quite frankly you are a quack.
- chriswastaken, on 11/08/2009, -0/+2@pln2bz But at least they have a Funny moderation. Oh, I guess you've never seen one those.
- APODNereid, on 11/10/2009, -0/+2pln2bz, I just don't get it.
The only simulations (of galaxies, using codes which are consistent with certain aspects of plasma physics) that I have seen published are those by Peratt ... and they are all over 20 years' old.
And they (the published results) do NOT describe (or can be mapped to) the actual, observed behaviour of real galaxies.
The failures (gross inconsistencies between simulation and actual observations) are many, and of many different kinds; e.g. presence of bulges and nuclei in real galaxies; inter-arm mass (and light); same rotation curves from stars, (neutral) gas, and plasma; stellar populations much older than the simulations require; and complete lack of any sign of the inter-galactic field-aligned currents which supposedly create the galaxies in the first place.
The similarities in the Birkeland terrella images and the rings of Saturn are not the least bit convincing. For example, Birkeland's simulation produces self-luminous rings, Saturn's (and Jupiter's, Uranus', and Neptune's) are not (they shine only by reflected sunlight, or planet-light).
But perhaps the most perplexing thing is that none of the sources you cite seem to have any mechanism for review! Indeed, with the exception of the Peratt 1986 simulations, and the Birkeland early 20th century material, no primary sources are cited! Where's the bedrock feature of science, objective INDEPENDENTLY VERIFIABLE evidence? - APODNereid, on 11/08/2009, -0/+2@pln2bz: Who wrote this, I wonder? "The very origin of dark matter originated because galaxies were observed to be rotating far too fast on the outer edges -- almost as if the galaxy was a fixed plate."
Surely it can't have been an engineer, can it? I mean, the rotation curve of a fixed plate is a straight line .. with a non-zero slope (i.e. it is not flat). Yet spiral galaxies have flat rotation curves (beyond a certain radius - "on the outer edges"), and it is this flat part which is so hard to explain using only the observed mass (stars, the interstellar medium). No engineer would make such a silly mistake, would they? - APODNereid, on 11/11/2009, -0/+2We're talking science ... objective evidence, independently verified, quantitatively testable hypotheses, ... that sort of thing.
The Miller experiments were certainly interesting ... but, as modern analysis clearly shows, there was no unambiguous signal of any aether.
http://arxiv.org/abs/physics/0608238
Of course a NULL result can be significant ... if the hypothesis it tests is clear, and rigorous.
Now if you, pln2bz, truly believed what you write, why aren't you spending your time (and money) doing the tests? I mean, where are *your* hypotheses? *your* independent (quantitative) analyses?
In short, what are *you* doing to ensure that "all possible explanations" are, indeed, being ruled out? - fastguyrules, on 11/07/2009, -0/+1I'll lose many good friends to this game.
- freakFlag, on 11/07/2009, -0/+1/me calls Woody Harrelson
- HenryKillinger, on 11/07/2009, -0/+1Bahahaha.
- sierrabravo, on 11/07/2009, -0/+1You don't know the power of the Dark Matter! Join me, and we will rule the Galaxy as father and son!
- DanielPhermous, on 11/07/2009, -0/+1It's not nearly as powerful as Doesn't Matter.
- BetaUser, on 11/07/2009, -0/+0No, it's not. At least with religion (generally speaking), you have well meaning people who really believe saying "it's God's will" is enough because they have allowed it to be for them. A small subset of those people will be open enough to learn that even in God's will, he set's order to things that follow rules and science, if anything, is the search to find and understand those rules.
Science vs Religion is the wrong argument to have in my opinion as they are one in the same. Religion, spirituality seeks to have a relationship with God and science seeks to know him by understanding what he's done whether it be create the universe and everything in it.
So maybe when scientific subjects come up, please spare your audience the mention of God. Science, like the existence of God, is true whether you believe it or not, and doesn't need your jabs at religion to affirm it's importance. - BetaUser, on 11/07/2009, -0/+0Thank you Greywren, very good explanation. Basically, it's a version of the simplest explanation is probably correct. And MOND wants to come along and take a simple proven explanation, and add seemingly arbitrary modifications to it so that the predictions can fit the observations.
If that's the case, that just sounds like bad science. I can see why it's ostracized. However, i'm always leery of just outright dismissing someone. I'm sure the first person to postulate that the sun didn't rotate around the earth sounded like a quack also, I mean, you CAN observe the sun moving in the sky, am i right. It took people to think outside the box and offer that the earth could be moving and the observations be the same.
It might be that way with gravitational theories. Something comes along that looks at old theories in a new way. I'm not saying that MOND is it, but the moment you start eliminating things without having the full answer yourself, you don't know if you're actually eliminating the correct answer. - chriswastaken, on 11/07/2009, -2/+2I think you meant to write this for /.
- freakFlag, on 11/07/2009, -2/+2Yo dark matter I'm really happy for you imma let you finish but Newton had one of the best theories of all time
- pln2bz, on 11/10/2009, -2/+1Why are we spending so much time talking about me? Who the hell cares what *I* think? The point is the theory, and ad hominem attacks are a clever (yet obvious) way to get people to become disinterested in reading more about the Electric Universe ...
APODNereid is not telling you guys something which is very important. Not only can galaxies be simulated on supercomputers without dark matter, but plasma experiments performed by one of the world's leading plasma physicists have also demonstrated that EVERY STAGE OF THE PIC SIMULATION can be replicated within a laboratory using electromagnetic (as if there was any other kind ...) plasmas. From Wal Thornhill's site, http://www.holoscience.com/news.php?article=2m1r5m ... ...
"And so that there can be no objection, the computer simulations have been backed up by experiments in the highest energy density laboratory electrical discharges—the Z-pinch machine. The experiments verify each stage in development of the PIC simulations."
Much of the public may not be familiar with this practice of replicating computer models for astrophysical objects within the laboratory. But that's one of the freebies you get with electromagnetic plasmas (in contrast to the gravitational plasmas proposed by astrophysicists). Plasmas scale over numerous orders of magnitude, meaning that we can perform laboratory experimentation to validate the bulk of what is being claimed by the EU Theorists. We call this "laboratory astrophysics", and Kristian Birkeland was the first to perform such experiments with his terrella. Many of the experiments that Birkeland performed generated unusual objects, which at the time people couldn't make much sense of. However, as we've explored more of space, we've come to see amazing similarities between Birkeland's results and observations of actual planets in our own solar system. It takes incredibly dogmatic people to ignore such striking similarities. For instance, Saturn's rings ... http://www.thunderbolts.info/tpod/2007/arch07/0712 ... More pictures here ... http://www.plasma-universe.com/index.php/Texts:On_ ...
In most disciplines of science, when faced with an experiment that can explain something and the option for blaming invisible entities, it would be absurd to even discuss which direction the investigation should proceed. But, when it comes to cosmology and astrophysics, our common sense has been undermined. We've been led to believe that anything is possible. And there's a good reason for that: some of the science is indeed strange on the surface. But, it is only strange to those who refuse to understand the universe's dominant state of matter -- plasmas. Once you understand how plasmas tend to actually behave within the laboratory, it becomes clear that astrophysicists aren't modeling plasmas properly because it becomes clear that plasmas are fundamentally electromagnetic. - bcronos, on 11/07/2009, -3/+2The last paragraph says it all... Bravo!
- yeeaauuh, on 11/06/2009, -3/+1Dark matter. So dark you can't even see it. meh.
- HenryKillinger, on 11/07/2009, -3/+1Still a more respectable fight than Science vs. "GOD'S WILL."
- pln2bz, on 11/07/2009, -3/+1Slashdot is a joke when it comes to the natural sciences. As a computer engineer myself, I used to read Slashdot religiously. However, at some point in time, I started reading materials which are critical of the conventional natural sciences ... geology, archaeology, cosmology, astrophysics, etc. Many of these critics -- like Charles Ginenthal -- make excellent arguments on topics like the accuracy of absolute dating, the extinction of the woolly mammoths and how dinosaurs as large small airplanes could have flown on Earth. However, when you attempt to discuss these interesting topics on /., all you get is a bunch of close-minded belief-driven arguments by engineers who have never read any history of science. It's just not popular amongst that crowd to imagine that humans make mistakes. And since people tend to buy books with which they generally already agree, Slashdotters (and engineers in general) essentially insulate themselves from against-the-mainstream views. When somebody gets out of line and tries to discuss something there like the Electric Universe, Slashdotters resort to public ridicule in an attempt to ostracize those who think different. It's not so much about exploring creative lines of logic in an attempt to solve long-standing problems -- as that would require a thorough, honest investigation. On Slashdot, it's about group-think and learning through memorization -- as any good engineer will tell you.
I'm an engineer. I know what it's like to build semiconductor circuits, and to imagine that humans have only a few more years before we've figured out how to stop human aging, how to adjust the temperature of our planet, how to build elevators to space, etc. What happens when people don't read the history of science is that they are vulnerable to "prophets" (some call them futurists) who will convince them that we are on the brink of some amazing future if we only wait another five or ten years. Our cars still do not fly.
Meanwhile, those of us who are reading the history of science, who are paying attention to astrophysical press releases and who aren't afraid to read about theories which may not actually be true, gain a context which makes the conventional perspectives seem narrow-minded and even hostile to new ideas ... "You have a new cosmology? Where's the math? What do you mean it's not quantified?" ... Lost in all of the attempts to debunk are honest attempts to foster the creation of alternative, more predictive cosmologies. While the cosmologists and astrophysicists scramble to explain the daily onslaught of surprises, they simultaneously convince the public that their models can accommodate the new finding. But they never mention that each failure to predict is an indication that the model is flawed -- possibly even dramatically.
And round and round we go. The cycle has already been set. Unless somebody figures out how to break out of it, your children will be talking about the same exact mismatch between Relativity and Quantum Mechanics that we grew up with.
When it comes to the natural sciences, Slashdot is the wrong place to go. I'd take holoscience.com any day over the garbage on Slashdot. - pln2bz, on 11/07/2009, -3/+1And what about the scientists running the LIGO interferometer experiment? Are THEY quacks? From "LIGO Sheds Light On Cosmic Event"...
"LIGO's contribution to the study of GRB070201 marks a milestone for the project, says Caltech's Jay Marx, LIGO's executive director: "Having achieved its design goals two years ago, LIGO is now producing significant scientific results. The nondetection of a signal from GRB070201 is an important step toward a very productive synergy between gravitational-wave and other astronomical communities that will contribute to our understanding of the most energetic events in the cosmos.""
Within an environment where mainstream scientists will eagerly call a NULL result "significant" and a "major milestone" presumably in the quest to get additional funding, what are we to make of the same people calling the aether interferometer experimenters quacks?
Re: "Not only that but CERN and all the other particle physics groups were conducting experiments on the relativistic dynamics of particles up until the 80s until they decided it wasn't worth trying to find anything wrong with it anymore."
From "The Invisible Universe" by Gerrit Verschuur ... "Many research scientists, especially the theoretically inclined, 'know' so much that their chance of making a lucky or creative discovery may be severely curtailed. If we know too much, our vision is sometimes narrowed to the point where new opportunities are not seen. Jansky knew a little astronomy, but not enough for it to get in his way and cause him to reject the possibility that radio waves originating from the cosmos might be real ... the new field of radio astronomy was originally caught between two disciplines. Radio engineers didn't care where the radio waves came from, and the satronomers, '... could not dream up any rational way by which the radio waves could be generated, and since they didn't know of a process, the whole affair was (considered by them) at best a mistake aned at worst a hoax.'"
If more people would just read the stories of science that have led us to this current point, they'd have a much more honest view of the fallibility of establishment science.
Re: "The point is that some established physics has such a weight of evidence behind it that it cannot be realistically challenged, and only modified in subtle ways."
But, this is glossing over the social ramifiications of admitting that the past 100 years has been a mistake.
Re: "Since we know general relativity works in certain circumstances (a fairly broad set of circumstances), then not only should a new theory reproduce the same results in that regime, but it should do it in a logical, consistent and simple way"
It really all depends on how rigorous and creative scientists have been in ruling out possibilities. Today, there is so much emphasis placed upon consensus in science (like in cosmology) that it's not clear that all of the possible explanations are being ruled out. - pln2bz, on 11/09/2009, -4/+1That says a lot more about the Astrophysical Journal than it does about EMOND, as the idea is simple enough that anybody -- astrophysicist or not -- could understand it.
Wal Thornhill has written on the topic of EMOND on his holoscience site, and it should surprise nobody that the Astrophysical Journal lacks any papers on it as there would be little funding for such ideas (this is actually part of the problem). Keep in mind that these are the same people who have offered the public the current, untenable belief that both Quantum Mechanics and Relativity are simultaneously without a doubt correct (and anybody who questions it should be burned as a heretic!); and that 95% of the universe's matter is invisible to our instruments -- and yet, they still claim to understand the nature of the universe at something like a trillionth of a second after its creation. We can all be forgiven if our minds are just too feeble to understand such things, as the astrophysicists will just tell us that they have the math to prove all of it, and we surely won't understand any of that. If EMOND does not appear in this journal, it's probably due to the current trend of ignoring both common sense and competing paradigms in an attempt to get Nobel Physics Prizes (which is thought to only result with generation of proof for the Big Bang). But don't be confused into thinking that this has ANYTHING to do with trying to develop simple cosmological models which explain our observations, or some sort of honest, inquisitive search for truth.
Electrically Modified Newtonian Dynamics merely refers to gravity as a side-effect of electromagnetism. The gravitational constant is observed to be the least constant of all constants. For instance, stellar models actually use a different G than the accepted G in order to work. From Earth's magnetic field 'boosts gravity' New Scientist, 22 September 2002 ...
“Newton's constant, which describes the strength of the gravitational pull that bodies exert on each other, is the most poorly determined of the constants of nature. The two most accurate measurements have experimental errors of 1 part in 10,000, yet their values differ by 10 times that amount. So physicists are left with no idea of its absolute value.”
That's a major problem which not everybody agrees should be ignored or shelved for a later date. It clearly suggests to some people, quite reasonably, that G may not actually be a constant. Wal Thornhill proposes one possible explanation, which he calls EMOND. For the layperson just trying to understand what this theory says, and for open-minded astrophysicists interested in expanding on the idea, it may help to review two links ...
http://www.holoscience.com/news.php?article=q1q6sz ...
http://www.holoscience.com/news.php?article=89xdcm ...
As much as I would love to see papers on the subject in the Astrophysical Journal, there's so much nonsense in that journal these days pertaining to invisible entities (dark matter, dark energy, etc.) that we can all be forgiven for not needing to see any mention of EMOND there in order to read about it. After all, that appears to be the motivation behind Nereid's relentless campaign to convince people to ignore the Electric Universe: to undermine peoples' curiosity and desire to read about it. It's really curious that somebody who so obviously works for NASA (the APOD in APODNereid) would spend so much time (literally hours per day some days) trying to convince people to not read about the Electric Universe.
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