"ikenbot:  Has Our Galaxy's Dark Matter Gone Missing?  If a new study is true, then the search for dark matter just got a lot weirder. Our little corner of the Milky Way contains no observable concentration of the mysterious stuff whose gravity binds the galaxy, claims one team of astronomers.  That finding would present a major problem for models of how galaxies form and may undermine the whole notion of dark matter, the researchers claim. But some scientists doubt the reliability of the team's method for measuring the elusive substance.  ""This is not just some piddling little detail,"" says Frederic Hessman, an astronomer at the University of Göttingen in Germany who was not involved in the work. ""If this is right, it turns everything totally upside-down."" But that's a big if, says Julio Navarro, an astrophysicist at the University of Victoria in Canada: ""The argument is provocative, but it remains inconclusive, in my opinion.""  According to standard cosmology, we should be swimming in dark matter. Measurements of the afterglow of the big bang—the so-called cosmic microwave background—and of the distribution of the galaxies suggest that 85% of all matter in the universe is dark matter. What's more, decades of astronomical observations show that the stars within galaxies swirl about faster than they could if only the gravity of the others stars were holding them in. In fact, the speed with which the sun goes around the center of our galaxy suggests that dark matter ought to be about as abundant as ordinary matter at our distance from the galactic center, about 27,000 light-years.  But that's not what Christian Moni Bidin, an astronomer at the University of Concepción in Chile, and colleagues find. Using data gathered with several telescopes, they studied old stars called red giants in a cylindrical region a couple of light-years wide and extending 13,000 light-years above the plane of the galaxy.  Treating the stars a bit like atoms in a gas, researchers assumed that they were trapped in the gravitational ""well"" of the galaxy. So by studying distributions of the stars' speeds in three dimensions, they could deduce the well's shape and hence the total distribution of mass from both dark and ordinary matter along the cylinder. Subtracting the distribution of ordinary matter as determined from star counts would then reveal the distribution of dark matter.  Continue.."