Ghostly cloud discovered around Milky Way

The ghost of a previous galaxy? Or an unknown galactic phenomenon? Scientists aren't sure, but their findings of a faint ring of stars surrounding the Milky Way will change our image of our home galaxy. The torus is estimated to contain several hundred million stars, about 1% of the total number of stars in the Milky Way. This changes the prevailing picture of our galaxy as a simple spiral to a more complex galaxy, perhaps pointing to a long lost satellite galaxy from 10 billion years past.