One proposal is that the smaller halos do exist but that only a few of them end up becoming visible, because they are unable to acquire enough baryonic matter to form a visible dwarf galaxy. In support of this, in 2007 the Keck telescopes observed eight newly discovered ultra-faint Milky Way dwarf satellites of which six were around 99.9% dark matter (with a mass-to-light ratio of about 1,000).