In 1989 the unmanned spacecraft "Voyager 2" flew by Neptune. "Voyager 2" sent back pictures that gave most of the information that scientists now have about the rings of Neptune. The pictures also help scientists to know why the rings looked incomplete. Not only did the pictures give a closer view, but they also showed the rings in a way that cannot ever be seen from earth. From earth the rings are always seen with the light of the sun shining "towards" them. When the spacecraft went past the planet, it took pictures with the sun shining "behind" the rings, as well. Big "particles" in the rings looked dark against the sunlight, but all tiny dust "particles" (microscopic dust) shone brightly when the sun was behind it. This allowed the scientists to work out what the rings were made of, and how all the particles were arranged.