Did the Milky Way have a merger with another galaxy 12.3 billion years ago?! #shorts

By Dr. Becky

Community Score: 50% | 1.1K views | 3w

0 community ratings: null thumbs up, null thumbs down

How do you figure out how many mergers the Milky Way has had in its past? Well what Massari et al. (2026) did was look at the speed and properties of 39 globular clusters. And then they then fitted their data with different models that had either 2, 3, or 4 separate populations of globular clusters coming from different merger events in the Milky Way’s past. And their best fit model was 3 distinct groups of star clusters. So the black points all have similar properties and Massari et al. claim these are clusters that have formed within the Milky Way itself. Whereas the cyan points all have similar properties to the Gaia-Sausage-Enceladus. But there’s also a separate group shown by the red points, which have distinct properties. So if this is from another merger with the Milky Way when did it happen? Well it’s by looking for the youngest cluster in each group that you can put an estimate on when the merger occurred, since any clusters that formed after that would’ve then been part of