...after further review...
Chalnoth said:
Unobserved != unobservable.
And it is possible we are nearing the answer on what dark matter is:
http://arxiv.org/abs/1301.6243
There remains some skepticism as to whether the particles detected by DAMA/LIBRA are dark matter, but it is clear they are detecting
something.
Chalnoth, I have had some opportunity to investigate the "hot off" the press paper by the researchers administering the DAMA/LIBRA experiment. I have not assembled all the background material nor completed my review of all the relevant articles (which date back to the 1970s), that predicted the phenomena DAMA/LIBRA was designed to detect. (I have also been reviewing the work recently released by the researchers associated with the Planck project...which is also, truly remarkable and fascinating).
Before making my comment about the paper, let me first state that all of the work that has been done on this particular question...(speculating on, hypothesize about, predicting the effects of, and detecting evidence of an hypothetical "dark matter halo" as a dominant component of the total mass of the Milky Way), is of the first rank within the field of cosmology as it is presently explored.
Without taking anything away from the investigations that have been conducted for the past 4 decades on this subject as it particularly relates to the Milky Way, the impression that one comes to when reviewing the literature is that the component of speculation involved in the development of the entire hypothetical superstructure upon which current predictions and efforts to detect local dark matter are based does not inspire confidence that the analysis or data have a meaningful explanatory value of very much at all, including, what aspect of what phenomena they might, in fact, be detecting.
The level of speculation involved at the most fundamental level of the hypothesis is for me, the first cause for substantial reserve regarding the significance of the data reported in the cited paper, based as it is, on a model of DM associated with the Milky Way.
A review of the papers published on the rotational dynamics of the Milky Way yields a clear sense that a unequivocal model of the rotation curve for the entire system does not presently exist, though the endeavor to build it up (populate the data), is worthy and admirable. The best "fit" is based on a statistical model of discrete rotation velocities of a relatively minute sample of galactic objects. And, it appears that the level of uncertainty involved in determining each object's relative velocity is itself a cause for doubt, such that, taking all the difficult challenges these researchers have before them in trying to develop sufficient data to establish a meaningful rotation curve for our spiral galaxy, the ability to predict how much dark matter might exist and what effect it is having on the dynamics of the system, and so on and so forth...well, it does not inspire much confidence at this stage of the investigation that we know very much on anything or that we can reach any particular conclusions about what phenomenon these detectors are evidencing.
From my point of view, the model used to develop the data on the rotational dynamics of the Milky Way is unduly speculative, unnecessarily analytically complex, and otherwise frought with uncertaintly. That is, it is my view that a lot of this could readily be resolved, and the results of these researchers work taken with a much higher degree of confidence than anyone but themselves at the present time believes their work deserves.
Fundamentally, I maintain that until they obtain empirical data from an experiment sufficient to demonstrate how light behaves across cosmologically relevant distances, these researchers have little hope of developing a sufficient interpretation of the rotational dynamics of the Milky Way, (or any other galactic system in the universe that apparently exhibits rotational dynamics that violate the virial theorem), to warrant a meaningful degree of confidence in their results.
The only measuring apparatus we have available is light. In an unobstructed, field free, static vacuum, we presume that the metric governing the propagation of light is Minkowskian. I think we need to verify whether or not that is true. With that accomplished, we can go forward with a much greater degree of confidence that the data and the hypothesis are really telling us something reliable about the universe we live in...so that we do not have to proceed with the nagging feeling that every new phenomena we encounter will be creatively explained by a heretofore unthought of and unpredicted "ad hoc" solve.
It is interesting that until the latter part of the 20th century, physicists, astronomers and cosmologists published their discoveries with a degree of reserve about the meaning of their results which I find refreshing, admirable and ultimately, inspiring of confidence. Now, everyone writes up their speculations as if they have fully, unequivocally, and indisputably explained the subject matter at hand, without a hint of reference to the level of uncertainty that lies at the foundation of their hypotheses.
Nothwithstanding these remarks, it is clear that the DAMA/LIBRA project has yielded data which means something, and Bernabei, et al, make a compelling argument that data related to what their detector has detected is different and more definitive than the results obtained by 20+ other research teams seeking by various methods and at various latitudes to detect the same thing...