A team of astronomers using the Subaru Telescope on Maunakea have charted the outermost edge of our Milky Way Galaxy. The team selected two very specific types of stars that are bright enough to be observed at such extreme distances, and then measured distances to hundreds of them. They discovered that beyond about half a million light years from the center of the Milky Way, the numbers of these stars dropped off sharply, defining the outermost edge of the Galaxy. Besides demonstrating the extraordinary scale of our home galaxy, measurements like these will give astronomers important clues into how both it, and other galaxies in the universe, formed.
Learn more about this finding in the Subaru Telescope press release.