This movie simulates several passages of the Sagittarius dwarf galaxy past the galactic center (GC) of the Milky Way over the course of 8 billion years. The blue and red particles represent dark matter and stars, respectively.
In this computer-generated image, a red oval marks the disk of our Milky Way galaxy and a red dot shows the location of the Sagittarius dwarf galaxy. The yellow circles represent stars that have been ripped from the Sagittarius dwarf and flung far across space. Five of the 11 farthest known stars in our galaxy were probably stolen this way.