Professional astronomers and volunteers working with the Backyard Worlds: Planet 9 citizen science project have spotted the oldest and coldest known white dwarf ringed by dust and debris. The discovery is described in a paper in the Astrophysical Journal Letters. In this illustration, an asteroid (bottom left) breaks apart under the powerful gravity of LSPM J0207+3331, the oldest, coldest white dwarf known to be surrounded by a ring of dusty debris....