Astronomers Think They've Finally Found The Edge of The Milky Way

Researchers analyzed over 100,000 giant stars from APOGEE, LAMOST, and Gaia to map the Milky Way’s star-forming disk.

They found a U-shaped stellar age pattern that points to a sharp drop in star formation between 11.28 and 12.15 kiloparsecs from the Galactic center.

This places a practical edge to the Milky Way’s active star-forming region at roughly 40,000 light years from the center.

Beyond that boundary, the outer disk appears to be dominated mostly by older stars that likely migrated outward.