A binary star system in which a white dwarf accretes matter from a normal companion star can be a ticking bomb. In this animation, we see such a system from a distance. The white dwarf packs more mass than our sun's into a volume about the size of Earth. Matter streaming from the red star accumulates on the white dwarf until the dwarf explodes. With its partner destroyed, the normal star careens into space. This scenario results in what astronomers refer to as a Type Ia supernova. Because they explode with similar brightness and can be seen across the universe, Type Ia supernovae provide astronomers with information about the distant cosmos.