Shell structures found in the Milky Way could be a clue to the history of our galaxy

Shell structures in our Milky Way are evidence of a huge collision between it and another dwarf galaxy, astronomers have found.

The crash happened nearly 3 billion years ago, when the dwarf galaxy fell into the middle the Milky Way and was torn apart by the collision.

But the merger has left behind evidence in the shape of formations, the first such “shell structures” ever found in the Milky Way, that shed more light on the collision as well as potentially explaining other phenomena.