Crater 2 Dwarf

Crater 2 is a low-surface-brightness dwarf satellite galaxy of the Milky Way,[1] located approximately 380,000 ly from Earth.

Its discovery in 2016 revealed significant gaps in astronomers' understanding of galaxies possessing relatively small half-light diameters and suggested the possibility of many undiscovered dwarf galaxies orbiting the Milky Way.

[3] The galaxy has a half-light radius of ~1100 pc, making it the fourth largest satellite of the Milky Way.

[3][4] Despite the large size, Crater 2 has a surprisingly low surface brightness, implying that it is not very massive.

[6] This unusually low velocity dispersion was predicted using Modified Newtonian Dynamics, an alternative to the dark matter hypothesis.