Submission + - Binary Black Hole, One Step Closer to Dark Matter (sciencemag.org)
eldavojohn writes: "On the 210th meeting of the American Astronomical Society (27-31 May 2007 in Honolulu, Hawaii), an important matter was discussed (pun intended). The issue at hand was over the existence of dark matter and, thanks to several observed events, we may now have proof positive of dark matter and some of its properties. Objects consisting of dark matter are believed to be invisible making them rather hard to see. However, it is believed that once in a while these "massive compact halo objects," or MACHOs, pass between us and a star, amplifying the light like a gravitational lens (since the object is invisible yet still has the property of gravity like normal matter). Using mountaintop triangulation here on earth, a team of researchers have timed a microlensing event and determined that it happened within the Milky Way's Halo, a vast sphere of sparsely populated space that is still part of our galaxy. We've discovered black holes in this region but now there is believed to be a 'double black hole': "Further analysis of the observations also reveals that the lens consists of two bodies, weighing in at three and seven times the mass of the sun, respectively. Stars that massive would be visible, so the MACHO is probably a binary black hole, according to team member Subo Dong, also of Ohio State. Future observations will be needed to determine whether normal dark matter consists mainly of black holes." For the gritty details, read the paper up for review."
