The Large and Small Magellanic clouds (LMC and SMC) are galaxies just outside the Milky Way, named after the explorer Magellan. These minor galaxies appear to be gravitationally bound to our Milky Way galaxy because they have left a trail of debris behind them, called the Magellanic stream, that curves around in a way that seems to show that they are orbiting our galaxy, see the schematic below:
However, as for almost every orbit on a cosmic scale (galaxy clusters, disc galaxies, dwarf galaxies, globular clusters, Proxima Centauri) the observed orbital velocity is so high that the orbiting mass should break free and zoom off to infinity. The observed orbital velocity of the LMC around the Milky Way is 378 km/s (Kallivayalil, 2013). If we assume Newtonian physics and that the Milky Way has only baryonic (normal) matter, this predicts an orbital speed v = sqrt(GM/r), where G is Newton's gravitational constant, M is the Milky Way's mass and r is the radial distance. This predicts that the maximum orbital velocity that the LMC can have without breaking away is 75 km/s. Oops. So, the LMC should have broken away, but the Magellanic stream suggests it hasn't.
If we assume the usual amount of dark matter in the galaxy, so boost the galactic mass by a factor of ten by adding an invisible and unexplained new kind of matter, then this predicts a maximum orbital velocity before breakaway of 237 km/s, so the LMC should still break away in contradiction to the Magellanic Stream.
MiHsC says that because of its low acceleration outside the galaxy, the LMC has lost some inertial mass and it predicts the following orbital speed, the second term being due to MiHsC:
v = sqrt(GM/r + 2c^2r/Theta)
where c is the speed of light and Theta is the Hubble scale. The MiHsC maximum speed for LMC boundedness is
v = 967 km/s
The observed orbital velocity of the LMC is 378 km/s, so from these examples you can see that MiHsC predicts that the LMC is bound to the Milky Way and is consistent with the observation of the Magellanic Stream that seems to show a bound past trajectory for it. Of course, you can mess around with dark matter arbitrarily till you get the answer you want, but that arbitrariness is deeply abhorrent.
References
Kallivayalil et al., 2013. http://arxiv.org/abs/1301.0832
McCulloch, M.E., 2012. Testing quantised inertia on galactic scales. Astrophys. Space Sci., 342, 575-578. http://arxiv.org/abs/1207.7007
29 comments:
Nice observation pointer, though MOND or MoG or CDM or axions or... What you really need is a prediction specific to MiHsC which no other theory makes. Is there anything like that?
Actually, there are other theories which account for many of the anomalies found in standard Big Bang cosmology. They are subsumed under the general category Plasma Cosmology. Perhaps the best summary and explanation is a book by Donald Scott:
http://www.amazon.com/Electric-Sky-Donald-E-Scott-ebook/dp/B002NGO5MI/ref=sr_1_1?s=digital-text&ie=UTF8&qid=1442624878&sr=1-1&keywords=electric+sky
There is a web page that directs you to summaries of the various topics covered in the book:
http://electric-cosmos.org/
This site contains a number of links to other sources:
http://www.electricuniverse.info/Introduction
Warning! You will find subversive material promulgated by the arch enemies of the state Halton Arp and Emmanuel Velikovsky. Proceed at your own risk.
In reference to Mike's illustration:
http://www.google.com/imgres?imgurl=https://www.thunderbolts.info/wp/wp-content/uploads/2014/04/1024px-Messier51_sRGB.jpg&imgrefurl=https://www.thunderbolts.info/wp/2014/04/21/galactic-maelstrom/&h=667&w=960&tbnid=zYbY5X7NEWl7xM:&docid=mP77A2uV5SnsQM&ei=-9f8VZv9B4LJeNbindAJ&tbm=isch&ved=0CEQQMyhBMEE4ZGoVChMI2-butJWCyAIVgiQeCh1WcQea
I just read a little article on www.phys.org about how 'dark matter' is supposedly causing stellar vibrations by dark matter 'hiding' within the stars. Going by analogy, I could also claim that whenever I open my purse, there's less money in it than I expected. When I search my purse for the difference, I simply can't find it. But wait! What, if the missing money vibrates and so I could find it by perhaps applying triangulation? Genius! ...
But on a serious note - 'dark matter' is becoming a laughing stock more and more. Any ad-hoc approach like this is like the hammer syndrome: When you have a hammer, there's nails everywhere. Appreciating that the physical origins of gravity and inertia aren't even vaguely explained in contemporary physics - behaviour described yes, but the physical mechanisms not explained.. a vital difference that many don't understand - I consider 'dark XYZ' approaches as non-scientific and eventually worthless endeavours that are just in place to secure workplaces for 1000's of pseudo scientist. Instead of 'dark XYZ', we could just say God's ways are mysterious and call it a day.
Luckily, there's still scientists around who work like they're supposed to.
Qraal: Excellent point, the problem is that dark matter is so flexible that it can be used to explain almost anything. I've seen it applied, in a different way in each case, to anomalies from galaxy rotation to the flyby anomalies (Adler, 2011) and even the extinction of the dinosaurs! The fact that it is so flexible means that it is neither predictive nor falsifiable. How physicists can accept such a thing I do not know. MoND is less vague but still has an adjustable parameter. To go to a place outside the remit of these flexible theories I have focused on lab anomalies like Podkletnov's, Tajmar's and the emdrive, but I seem to have stirred up a hornet's nest!
There are things I can do. For example, a direct vacuum experiment with a spinning disc is planned, and I'm trying to work out how to model globular clusters embedded within a galaxy, which dark matter cannot be applied to. Also, MiHsC makes some unique predictions, for example: for some specific accelerations the Unruh waves that cause inertia in MiHsC fit exactly within the Hubble scale boosting inertia, for others they don't, so an object going into deep space should show slight variations in its inertial mass as it passes through these resonance zones which should surround large masses like concentric spheres, wider spaced further out.
Roy: I appreciate there are other theories out there, and I'd like them all to be more openly discussed. I've come across Halton Arp's interesting work. The present dark matter bandwagon is smothering everything else, like weeds in a garden.
ZeroIsEverything: Amen to that, and I'm often disappointed at the amount in my wallet but I'm realist enough to accept it as a real crisis :) The problem in physics is how to disprove the dark matter delusion before it ends up lasting for 1500 years of non-progress like Ptolemy's epicycles. It's un-falsifiability doesn't help.
It seems the real problem lies within the academic educational system. When physics advanced by leaps and bounds, e.g. in the beginning 20th century, physicists (and scientists in general) were also considerably educated in philosophy and logics. I live in Germany, and I can see this trend since many years that new generations of scientists are less and less educated in these vital areas of knowledge. More and more focus is set on young people to become academic proletariat, in the sense they should just work for someone else and shut the hell up otherwise. Don't start thinking on your own, it's bad for your paycheck. So we get these incestuous dependency relations and loads of people who pretend to be physicists (because they work as physicists, but really aren't, because you also need profound understanding of philosophy and logics).
Innnnnteresting. A good refutation of the Dark Matter thesis and supporting data point for MiHsC.
ZeroIsEverything. Your phrase 'academic proletariat' well describes the phenomenon, which I have seen too, of physicists not willing to challenge groupthink/authority. It may well be partly a lack of philosophy, which can provide an objective framework to help people break out of groupthink. I suspect the advent of computers is partly to blame: they enable very complex fudges to be set up using the old paradigm (eg: dark matter) and then the intellectually lazy can't see the need for new thinking. It may also be partly the profit motive which is unfortunately taking over everywhere, and favours expensive solutions (eg: dark matter detectors) over cheap ones (eg: MiHsC on a piece of paper). I'm developing a new course at Plymouth at the moment on Space Exploration and will be giving all this a lot of thought.
"An important scientific innovation rarely makes its way by gradually winning over and converting its opponents: What does happen is that the opponents gradually die out." - Max Planck
“Every great cause begins as a movement, becomes a business, and eventually degenerates into a racket.” - Eric Hoffer
Science is big business, no matter how small. Grants, faculty positions, tenure. Acolytes must profess the catechism lest they be cast into the outer darkness.
I think the dogmatic belief comparison is nonsense. "Dark Matter" is a theoretical pointer for further research.
Let's put aside the unseemly name-calling and judge research directions on their merits. Here's how I see the options:
(1) Dark Mass - whether it be neutrinos, axions, WIMPs, etc etc
(2) Modification of Gravity - Moffat's particular theory and the dozens of extensions of General Relativity that have been proposed.
(3) Modification of Inertia - Mike's theory, plus various Machian concepts out there.
Until we have observational tests that distinguish the options, any of them are equally valid approaches. I'm sure Mike would agree that his theory is a work-in-progress and not some "New Dogma" to be ladled out from textbooks to under-grads (though a discussion of options would be welcome in any controversial area of physics.)
qraal,
There is another option: Plasma Cosmology.
Plasma Cosmology is grounded in real-world, in-situ experimentally verified physics. It accounts for the phenomena of the observable universe without recourse to the zoo of theoretical, unverifiable, ad-hoc entities invented to support Big Bang cosmology - inflation energy, dark energy, dark matter, singularities, black holes, neutronium, strange matter, MOND, chameleon neutrinos, axions, MACHOs, and so on. It also explains many of the observations that are puzzling to conventional theorists.
This site is a pretty good introduction to the basics:
http://electric-cosmos.org/indexOLD.htm
Roy,
I read Eric Lerner's book many years ago, so I am well acquainted with Plasma Cosmology. Unfortunately, contrary to what it says on the label, it's not really a cosmology and more of a grab-bag of ideas and requires some exotic failure of gravity on the large scale to be viable. There is some very interesting work on plasma processes in the solar system and the asterospheres of other stars, but it's hard to see it applying on the scale they imagine.
qraal: I do agree that MiHsC is a work in progress, and of course it should be considered fairly along with all the other options. Objective comparison is badly needed. In my opinion the theories should be judged on a number (Occam's number?) that is defined, in a way to be determined, as the amount of success they have in predicting the data divided by the amount of arbitrary 'fudging' that humans/computers have to do. So dark matter can fit a lot of the data but is adjusted arbitrarily 'until' it fits, so it would score big/big~1. MoND fits well, but is adjusted with one parameter, a0, so it would score higher: big/1=big. MiHsC fits well too but has no fitting parameter at all so it would score big/0=infinity :) Well, it's never so simple, but you get the idea..
In the early universe, theta would have been smaller, meaning the MiHsC term would be larger. Is that something that has been observed, faster rotation in more distant galaxies? Or, am I making an incorrect assumption?
Ryan: Yes, if we assume c is constant in time (there's no proof it is) then a smaller Theta in the past would mean a greater MiHsC effect, less inertial mass for an early galaxy's edge stars, and an apparently smaller or tighter galaxy in the past - but this is ignoring everything else going on and the data is patchy:
http://news.nationalgeographic.com/news/2014/01/140107-hubble-oldest-frontier-science-space-astronomy/
In line with these smaller early galaxies, it is interesting to note that MiHsC does suggest something like this:
http://physicsfromtheedge.blogspot.co.uk/2013/05/entropy-and-surface-area.html
The difficulty with looking at such a distant and early epoch is that the data is indirect and requires a lot of assumptions about how well we can see them, observer bias, galaxy evolution and other things. I prefer looking at more direct data.
if intertia is dependant from the size of the observable universe, would that mean that inertia was different in the early (= smaller) universe shortly after the big bang?
after scrolling up and reading i retract my question :) (i'm the retractor)
If the change in inertia tracks the Universe's expansion, then it should change at about 1 part in 10^18 per second. I wonder if that's observable?
Intriguingly that rate of change is about the same to match the proportional increase that's observed in Earth's orbit (it expands at about ~7.5 metres per year based on space-probe signal measurements of the AU.)
qraal: Can you confirm your data (7.5 m/yr)? I tried this, but the data I had on the change in the AU was 15 cm/yr.
Hi Mike
Most recent literature says ~7.5 metres per year. Older references say ~15 m/yr.
It's funny, that dark matter accumulation predicts exact opposite:
http://physicsworld.com/cws/article/news/2010/jan/25/suns-appetite-for-dark-matter-may-affect-earths-orbit
So dark matter proponents came to surprising conclusion: "In fact, this conclusion is just about consistent with observations, combined from a variety of different sources, showing an increase in the astronomical unit of between 5 and 9 cm per year."
I am not at all persuaded about MiHsC yet, because for me, almost all observations it "predicts" are hard to verify or find original sources and I also can't do the calculations myself (I either miss the data or don't understand the geometrical model used to "predict" some result)... but I am really starting to be amazed, how theory so inconsistent, incoherent and unverifiable as dark matter could have managed to attract so much mainstream media attention.
qraal: could you reference a paper on that 7.5 m/yr? I've seen data suggesting everything from 15 cm/yr to 7.5 m/century. Thanks.
Michael Polak: Well, to be sceptical, but open too, is the best approach.
To address your first point on inaccessible data: all the observations I've used as tests: Pioneer, flybys, galaxy rotation, cosmic acceleration, low-l CMB background anomaly, have been published and peer reviewed except Tajmar's experiment (conference papers only) and the emdrive (very little has been officially published yet).
On your second point on being able to reproduce the calculations: all the predictions can be reproduced on a sheet of paper, but I guess there are two hurdles to overcome. The first is that you have to start thinking in term of horizons and what they allow or not, and the second is that I've had to simplify when modeling complex systems like galaxies. If you could mention a specific problem, I'll try to explain.
Mike: I think my knowledge of physics is too limited to proceed on my own, without guiding. On the other hand, complex computer models of object like galaxies are today easily available to proponents of any theory, thanks to excess computing power available to almost anybody. But it may require some basic knowledge of paralelization of task, so maybe I can help someone with theoretical knowledge in the field to run simulations faster, or on more machines at once, or something like this.
(I am also sceptical about understanding universe through computer simulations... but as long as math is involved, which seems to be case o MiHsC and its basic "magic formula", the simulations are relatively easy to setup, and even when the accelerating objects are interacting mainly with horizons and not with themself, it maybe be useful to eg. look on objects like galaxies without simplifying and actually run the basic formula for billions of objects inovolved.. this is what is great about Internet: on the one hand, it will delete your Wiki article, but at the same time, if you manage to create community of enthusiasts, you can crowdsource lot of tasks which would otherwise require lot of funding, time, etc.)
I still have trouble finding claims, that AU changes moret then few cm per year (and such change is within the uncertainty of the measurement...)
http://physics.stackexchange.com/questions/71652/how-fast-is-the-earth-sun-distance-changing
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