The Sagittarius Dwarf Elliptical Galaxy (Sag DEG) is a sattelite galaxy of the Milky Way Galaxy. Roughly 10,000 light years in diamaeter, it is currently about 70,000 light years from Earth and travelling in a polar orbit at a distance of about 50,000 light years from the core of the Milky Way.
Although it is one of the closest companion galaxies to the Milky Way, it was only discovered in 1994. Sag DEG is currently located behind the galactic core as seen from Earth. Based on its current trajectory, Sag DEG is poised to pass through the galactic disc of the Milky Way within the next hundred million years, and is the process of slowly being absorbed into the larger galaxy.
Sag DEG should not be confused with SagDIG, the Saggitarius Dwarf Irregular Galaxy, a small galaxy nearly 4 million light years distant.