Milky Way research reveals ancient galaxy mergers and boundaries

New research is providing deeper insights into the assembly and boundaries of the Milky Way galaxy. A study conducted by the National Institute for Astrophysics (Inaf) as part of the Carma project suggests that the Milky Way was formed through a merger with an external galaxy approximately two billion years after the Big Bang.

This finding addresses a period of uncertainty in galactic history. While previous research had confirmed a merger with the Gaia-Enceladus dwarf galaxy about ten billion years ago, this new evidence indicates that early foundational building blocks were incorporated much earlier than previously understood.

Complementary research published in ‘Astronomy and Astrophysics’ has also worked to define the galaxy's physical limits. By analyzing over 100,000 celestial bodies using data from the Gaia satellite, the Lamost telescope, and the Apogee spectrograph, scientists have estimated the distance to the galactic edge to be between 11.28 and 12.15 kiloparsecs. This suggests a total galactic diameter of up to approximately 100,000 light-years.