Milky Way astronomers discover evidence of ancient galactic cannibalism

Astronomers have discovered evidence of the Milky Way's earliest period of galactic cannibalism, identifying a “scarring” at the center of the galaxy left by a merger that occurred approximately 12 billion years ago.

As part of the ARMA (Cluster Ages to Reconstruct the Milky Way Assembly) project, researchers used ancient star clusters known as globular clusters to trace this event. This discovery pushes back the known timeline of the Milky Way's assembly by roughly 1.8 billion years, as previous reconstructions only reached back to approximately 10 billion years ago.

Using data from the Hubble Space Telescope, the team identified traces of this ancient collision, which significantly influenced the subsequent evolution of the galaxy. Chiara Zerbinati of the University of Bologna noted that the findings provide insight into the Milky Way's infancy and its fundamental origins.