This is very cool stuff indeed. If you can get your head around it.
Scientists appear to have discovered a whole mess o'li'l ole galaxies (satellites of the Milky Way). From my cursory read (I'm, like, busy, m'kay?) I think I understand that scientists found a bunch of satellite galaxies at Andromeda that appear to be "riding a stream of dark matter" and a similar such situation appears to be the case with our own Milky Way.