Over the past 30 years, astronomers have cataloged about 4,000 Kuiper Belt objects (KBOs), including a smattering of dwarf worlds, icy comets, and leftover planet parts. “I think that's the big thing that Rubin is going to do—fill out the gaps in our knowledge of the contents of the solar system,” she adds. “I think this will become a very hot field very soon, because of LSST,” says Amir Siraj, a graduate student at Princeton University who studies the Kuiper Belt. The Kuiper Belt is a graveyard of planetary odds and ends that were scattered far from the sun during the messy birth of the solar system some 4.6 billion years ago. While the Kuiper Belt is not completely static, it is, for the most part, an intact time capsule of the early solar system that can be mined for clues about planet formation.