We don't know for sure how many dwarf galaxies are attached to the Milky Way because they're dim and hard to see. There's at least 50 of them, and astronomers keep finding more. Among the dwarf galaxies are the ultra-faint dwarf galaxies, the smallest and least bright of them all. Regardless of their actual number, they're important because of what they can tell scientists about the early Universe. Scientist sometimes refer to dwarf galaxies in general as relics of the early Universe, because they can tell us something about the conditions in the Universe billions of years ago. The ultra-faint dwarf galaxies (UFDG) are an important population of dwarf galaxies because they're dominated by dark matter to a greater extent than other dwarfs. In new research published in the Monthly Notices of the Royal Astronomical Society, a team of researchers used powerful simulations to probe the starting conditions for UFDG.…