The latest addition to our area of space has been called the Crater 2 dwarf, and it lies around 380,000 light years away from Earth.
Gabriel Torrealba, Sergey Koposov, Vasily Belokurov and Mike Irwin, all from Cambridge University, made the remarkable discovery by analysing images taken by the VLT Survey Telescope in the high mountains of northern Chile.
In a paper published in the Monthly Notices of the Royal Astronomical Society, the team shed light on the details of the new galaxy.
Although it's not visible to human eyes, Crater 2 is enormous - it's the fourth-largest satellite of the Milky Way, our home galaxy which has more than 30 smaller galaxies circling around it.
Individual stars within Crater 2 are visible from Earth, but the galaxy as a whole is too far away to take up a large place in the night sky.
If it were closer, it'd make an impressive spectacle. As reported by New Scientist, Carnegie Obervatories astronomer Josh Simon says Crater 2 is brighter than almost all of the orbiting galaxies found in the last decade - emitting 160,000 times as much light as the Sun.
It may seem odd that such a vast and bright galaxy eluded astronomers' telescopes for so long, but according to the Cambridge team, the stars which make up Crater 2 are more spread out than usual, making it seem slightly 'ghostly' and not quite as eye-catching as a denser formation.
Crater 2 is one of our neighbours for the time being, but it could fall in to the Milky Way at some point - that's how our giant galaxy formed in the first place.
Crater 2, along with the Crater globular star cluster and three smaller dwarf galaxies are believed to be part of a group which is beginning to fall into the Milky Way, a process which will take eons.
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies