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MOND predicts dwarf galaxy feature prior to observations
August 30, 2013 at 1:13 pm
Is this a blow to the Lamdba-CDM, THE standard model of Big Bang cosmology? MOND was able to correctly predict the existence of certain dwarf galaxies. Recent observations have confirmed this prediction. Note: MOND does not need Dark Matter to explain the anomaly in the stars galactic velocities.
http://arxiv.org/pdf/1308.5894v1.pdf
http://blog.case.edu/think/2013/08/28/mo...servations
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RE: MOND predicts dwarf galaxy feature prior to observations
August 30, 2013 at 5:23 pm
Very interesting, but mostly beyond my scope of knowledge.
Even if the open windows of science at first make us shiver after the cozy indoor warmth of traditional humanizing myths, in the end the fresh air brings vigor, and the great spaces have a splendor of their own - Bertrand Russell
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RE: MOND predicts dwarf galaxy feature prior to observations
August 30, 2013 at 5:28 pm
The problem with Modfied Newtonian Dynamics, the idea that there is a break in the intensity of gravity at very low accelerations, is that if it works, we still don't know why it works. It kind of resolves the Dark Matter issue, though.
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RE: MOND predicts dwarf galaxy feature prior to observations
August 30, 2013 at 5:33 pm
(August 30, 2013 at 5:28 pm)Mister Agenda Wrote: The problem with Modfied Newtonian Dynamics, the idea that there is a break in the intensity of gravity at very low accelerations, is that if it works, we still don't know why it works. It kind of resolves the Dark Matter issue, though.
That it would, but as far as I'm aware it has no answer for accelerated expansion ("dark energy"). In addition, the theory swaps one unknown for another, as you imply. I'm staying on the fence for now.
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RE: MOND predicts dwarf galaxy feature prior to observations
August 31, 2013 at 10:24 am
(This post was last modified: August 31, 2013 at 10:28 am by little_monkey.)
(August 30, 2013 at 5:28 pm)Mister Agenda Wrote: The problem with Modfied Newtonian Dynamics, the idea that there is a break in the intensity of gravity at very low accelerations, is that if it works, we still don't know why it works. It kind of resolves the Dark Matter issue, though.
Yes, indeed a strong point that MOND has over Dark Energy models is that it can make prediction, while DE can't as you have to figure what is the ratio DE/(ordinary) M for each galaxy, but MOND has one universal equation applied to every single galaxy. But as you've stated, the drawback is that they have to postulate a threshold acceleration. And to be a viable theory, it would need to explain this threshold. I don't think GR can help in that regard. But who knows!
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RE: MOND predicts dwarf galaxy feature prior to observations
August 31, 2013 at 4:37 pm
(August 31, 2013 at 10:24 am)little_monkey Wrote: (August 30, 2013 at 5:28 pm)Mister Agenda Wrote: The problem with Modfied Newtonian Dynamics, the idea that there is a break in the intensity of gravity at very low accelerations, is that if it works, we still don't know why it works. It kind of resolves the Dark Matter issue, though.
Yes, indeed a strong point that MOND has over Dark Energy models is that it can make prediction, while DE can't as you have to figure what is the ratio DE/(ordinary) M for each galaxy, but MOND has one universal equation applied to every single galaxy. But as you've stated, the drawback is that they have to postulate a threshold acceleration. And to be a viable theory, it would need to explain this threshold. I don't think GR can help in that regard. But who knows!
Given the small magnitude of the threshold, maybe quantum mechanics would be a better place to look for the cause.
If I recall, excess mass implied by dark matter, but not MOND, is corroborated by several other lines of evidence, including behavior of galaxy clusters, gravitational lensing, and gravity induced redshifts. As I recall, these phenomenon behave inside the range predicted by dark matter, but outside the range consistent with MOND.
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RE: MOND predicts dwarf galaxy feature prior to observations
September 1, 2013 at 4:33 pm
(August 31, 2013 at 4:37 pm)Chuck Wrote: (August 31, 2013 at 10:24 am)little_monkey Wrote: Yes, indeed a strong point that MOND has over Dark Energy models is that it can make prediction, while DE can't as you have to figure what is the ratio DE/(ordinary) M for each galaxy, but MOND has one universal equation applied to every single galaxy. But as you've stated, the drawback is that they have to postulate a threshold acceleration. And to be a viable theory, it would need to explain this threshold. I don't think GR can help in that regard. But who knows!
Given the small magnitude of the threshold, maybe quantum mechanics would be a better place to look for the cause.
QM doesn't deal with acceleration at all. So nix that. 
Quote:If I recall, excess mass implied by dark matter, but not MOND, is corroborated by several other lines of evidence, including behavior of galaxy clusters, gravitational lensing, and gravity induced redshifts. As I recall, these phenomenon behave inside the range predicted by dark matter, but outside the range consistent with MOND.
These are not predictions as such, but DE does explain these phenomena quite well. That's why I don't see a paradigm shift. Dark matter is here to stay for quite a while.
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RE: MOND predicts dwarf galaxy feature prior to observations
September 1, 2013 at 4:43 pm
(This post was last modified: September 1, 2013 at 4:45 pm by LastPoet.)
This is out of my league in Physics, but I know one thing: we must gather more evidence to remove the ambiguities. The problem is that in these times, little spending is done in getting that evidence, profit being the drive for research. In other words, the invisible hand of the market uses money for wanking.
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