Researchers at the CfA have released a new paper studying the halo of our Milky Way, using data from the MMT’s Hectospec of more than five thousand stars. The global motions of the stars help decode information about the mass, structure and formation of the Milky Way. They find a strange “discontinuity” region about 30,000 light years away, which may be attributable to a star stream, an association of orbiting stars that may once have been a globular cluster or dwarf galaxy that has been torn apart by tidal forces. Read more here.