🌌 Astronomers Found the Remains of a Galaxy the Milky Way Ate 12 Billion Years Ago

The Milky Way did not grow up quietly.

Astronomers have found strong evidence that our Galaxy swallowed a substantial dwarf galaxy about 12.3 billion years ago — when the Universe was still very young. The merger happened roughly 1.8 billion years before the better-known Gaia–Sausage–Enceladus collision, previously one of the earliest major events firmly traced in the Milky Way’s history.

The clue came from globular clusters — ancient, densely packed groups of stars that preserve a kind of archaeological record of the Galaxy. Using extremely precise Hubble Space Telescope measurements, researchers identified a third distinct age-and-metallicity sequence among clusters in the inner Milky Way. That sequence points to a separate progenitor galaxy with a stellar mass of about 500 million Suns.

The team named the lost galaxy Low-energy-Kraken-Heracles, or LKH. Most of its stars appear to have been deposited within the inner 6,000 parsecs of the Milky Way, where their original identity has long since been erased by billions of years of mixing.

In other words, parts of the night sky above us may be made from the remains of another galaxy that disappeared before Earth existed.

Galaxies do not simply form. They assemble themselves by consuming one another.

#MilkyWay #Astronomy #Hubble #Galaxies #Cosmology #Science

https://www.nature.com/articles/s41550-026-02931-5