The Milky Way ate a whole galaxy 12 billion years ago — Hubble just found the leftovers: stars worth 500 million Suns
Fun fact about our home galaxy: it's a cannibal. Always has been. The Milky Way got big the way empires and sourdough starters get big — by absorbing everything nearby. And now the Hubble Space Telescope, 36 years old and still outworking all of us, has found the crumbs from one of its very first meals.
The crime scene
An international team of astronomers used Hubble to examine 39 globular clusters — dense, ancient balls of stars — in the inner regions of our galaxy, publishing the results in Nature Astronomy. They expected two populations in there: clusters born in the young Milky Way itself, and clusters stolen from a dwarf galaxy called Gaia-Sausage-Enceladus (real name, I don't make the rules) that got swallowed about 10 billion years ago.
Instead they found a third group. Older than the Sausage loot. Younger than the homegrown stars. Which means: a separate, even earlier dinner.
Roughly 11.8 billion years ago — just 2 billion years after the Big Bang — a dwarf galaxy carrying about 500 million Suns' worth of stars slammed into a baby Milky Way and never left.
Meet LKH, the galaxy that became furniture
The devoured galaxy now has a name: Low-energy-Kraken-Heracles, or LKH, honoring three earlier papers that predicted something like it existed. At the time it hit, its stars made up a serious chunk of our galaxy's total mass. This wasn't a snack. This was a merger of near-equals, and only one of them got to keep the name on the door.
"We discover where the first significant batch of bricks came from," said lead author Davide Massari of Italy's Astrophysics and Space Science Observatory of Bologna — comparing the Milky Way to a house whose construction history nobody had ever seen. Turns out the foundation is partly imported.
Why this is quietly a big deal
- It pushes the documented history of our galaxy 1.8 billion years further back than before.
- It kills the tidy idea that the early Milky Way was built only from its own stars — some of the oldest stars around us are immigrants from a dead galaxy.
- The team dated it all using each cluster's age and metal content, measured with a precision that wasn't possible until now.
- And somewhere in the night sky right now, you can look at stars that formed in a galaxy that hasn't existed for almost 12 billion years.
So the next time someone tells you to let go of the past: the Milky Way has been carrying the remains of an entire consumed civilization of stars since before Earth was a rumor, and it's doing fine. Thriving, even.
